Document:

[EXHIBIT 4.6]

THIS WARRANT AND THE SHARES OF COMMON STOCK ISSUABLE UPON EXERCISE
HEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE "SECURITIES ACT") OR ANY STATE SECURITIES LAWS AND MAY
NOT BE SOLD, TRANSFERRED OR OTHERWISE DISPOSED OF UNLESS REGISTERED
UNDER THE SECURITIES ACT AND UNDER APPLICABLE STATE SECURITIES LAWS OR
THE ISSUER SHALL HAVE RECEIVED AN OPINION OF COUNSEL REASONABLY
SATISFACTORY TO THE ISSUER THAT REGISTRATION OF SUCH SECURITIES UNDER
THE SECURITIES ACT AND UNDER THE PROVISIONS OF APPLICABLE STATE
SECURITIES LAWS IS NOT REQUIRED.

                    SERIES C WARRANT TO PURCHASE

                      SHARES OF COMMON STOCK

                                OF

                          DENTALSERV.COM

                      Expires August 20, 2012

No.: W-C-07- __                            Number of Shares: 5,975,116
Date of Issuance: August 20, 2007

    FOR VALUE RECEIVED, the undersigned, Dentalserv.com, a Nevada
corporation (together with its successors and assigns, the "Issuer"),
hereby certifies that Vision Opportunity Master Fund, Ltd., or its
registered assigns (the "Holder") is entitled to subscribe for and
purchase, during the Term (as hereinafter defined), up to 5,975,116
shares (subject to adjustment as hereinafter provided) of the duly
authorized, validly issued, fully paid and non-assessable Common Stock
of the Issuer, at an exercise price per share equal to the Warrant
Price then in effect, subject, however, to the provisions and upon the
terms and conditions hereinafter set forth.  Capitalized terms used in
this Warrant and not otherwise defined herein shall have the
respective meanings specified in Section 9 hereof.

    1.   Term.  The term of this Warrant shall commence on August
         ----
20, 2007, and shall expire at 6:00 p.m., eastern time, on August 20,
2012; provided, however, in the event that the Share Increase (as
defined in the Purchase Agreement) has not been effected within ninety
(90) days following the Original Issue Date, the term of this Warrant
shall be automatically extended for a period of one (1) year and the
Issuer shall promptly issue to the Holder a new Warrant evidencing the
extension of such term (such period being the "Term").

    2.   Method of Exercise; Payment; Issuance of New Warrant;
         -----------------------------------------------------
Transfer and Exchange.
---------------------

    (a)  Time of Exercise.  The purchase rights represented by this
         ----------------
Warrant may be exercised in whole or in part during the Term.

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    (b)  Method of Exercise.  The Holder hereof may exercise this
         ------------------
Warrant, in whole or in part, by the surrender of this Warrant (with
the exercise form attached hereto duly executed) at the principal
office of the Issuer, and by the payment to the Issuer of an amount of
consideration therefor equal to the Warrant Price in effect on the
date of such exercise multiplied by the number of shares of Warrant
Stock with respect to which this Warrant is then being exercised,
payable at such Holder's election (i) by certified or official bank
check or by wire transfer to an account designated by the Issuer, (ii)
by "cashless exercise" in accordance with the provisions of subsection
(c) of this Section 2, but only when a registration statement under
the Securities Act providing for the resale of the Warrant Stock is
not then in effect by the date such registration statement is required
to be effective pursuant to the Registration Rights Agreement (as
defined in the Purchase Agreement), or (iii) by a combination of the
foregoing methods of payment selected by the Holder of this Warrant,
if cashless exercise is available.  In connection with the exercise of
the Warrants, the Holder shall be required to exercise Warrants
convertible into a minimum of one hundred thousand shares of Common
Stock in any single exercise.

    (c)  Cashless Exercise.  Notwithstanding any provisions herein
         -----------------
to the contrary and commencing one (1) year following the Original
Issue Date if (i) the Per Share Market Value of one share of Common
Stock is greater than the Warrant Price (at the date of calculation as
set forth below) and (ii) a registration statement under the
Securities Act providing for the resale of the Warrant Stock is not
then in effect by the date such registration statement is required to
be effective pursuant to the Registration Rights Agreement (as defined
in the Purchase Agreement) or not effective at any time during the
Effectiveness Period (as defined in the Registration Rights Agreement)
in accordance with the terms of the Registration Rights Agreement,
unless the registration statement is not effective as a result of the
Issuer exercising its rights under Section 3(n) of the Registration
Rights Agreement, in lieu of exercising this Warrant by payment of
cash, the Holder may exercise this Warrant by a cashless exercise and
shall receive the number of shares of Common Stock equal to an amount
computed using the following formula upon surrender of this Warrant at
the principal office of the Issuer together with the properly endorsed
Notice of Exercise:

	X = Y - (A)(Y)
                ------
                  B

Where   X =  the number of shares of Common Stock to be issued to
             the Holder.

        Y =  the number of shares of Common Stock purchasable upon
             exercise of all of the Warrant or, if only a portion
             of the Warrant is being exercised, the portion of the
             Warrant being exercised.

        A =  the Warrant Price.

        B =  the Per Share Market Value of one share of Common Stock.

    (d)  Issuance of Stock Certificates.  In the event of any
         ------------------------------
exercise of this Warrant in accordance with and subject to the terms
and conditions hereof, certificates for the shares of Warrant Stock so

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<PAGE>

purchased shall be dated the date of such exercise and delivered to
the Holder hereof within a reasonable time, not exceeding three (3)
Trading Days after such exercise (the "Delivery Date") or, at the
request of the Holder (provided that a registration statement under
the Securities Act providing for the resale of the Warrant Stock is
then in effect or that the shares of Warrant Stock are otherwise
exempt from registration), issued and delivered to the Depository
Trust Company ("DTC") account on the Holder's behalf via the Deposit
Withdrawal Agent Commission System ("DWAC") within a reasonable time,
not exceeding three (3) Trading Days after such exercise, and the
Holder hereof shall be deemed for all purposes to be the holder of the
shares of Warrant Stock so purchased as of the date of such exercise.
Notwithstanding the foregoing to the contrary, the Issuer or its
transfer agent shall only be obligated to issue and deliver the shares
to the DTC on a holder's behalf via DWAC if such exercise is in
connection with a sale or other exemption from registration by which
the shares may be issued without a restrictive legend and the Issuer
and its transfer agent are participating in DTC through the DWAC
system.  The Holder shall deliver this original Warrant, or an
indemnification reasonably acceptable to the Issuer undertaking with
respect to such Warrant in the case of its loss, theft or destruction,
at such time that this Warrant is fully exercised.  With respect to
partial exercises of this Warrant, the Issuer shall keep written
records for the Holder of the number of shares of Warrant Stock
exercised as of each date of exercise.

    (e)  Compensation for Buy-In on Failure to Timely Deliver
         ----------------------------------------------------
Certificates Upon Exercise.  In addition to any other rights available
--------------------------
to the Holder, if the Issuer fails to cause its transfer agent to
transmit to the Holder a certificate or certificates representing the
Warrant Stock pursuant to an exercise on or before the Delivery Date,
and if after such date the Holder is required by its broker to
purchase (in an open market transaction or otherwise) shares of Common
Stock to deliver in satisfaction of a sale by the Holder of the
Warrant Stock which the Holder anticipated receiving upon such
exercise (a "Buy-In"), then the Issuer shall (1) pay in cash to the
Holder the amount by which (x) the Holder's total purchase price
(including brokerage commissions, if any) for the shares of Common
Stock so purchased exceeds (y) the amount obtained by multiplying (A)
the number of shares of Warrant Stock that the Issuer was required to
deliver to the Holder in connection with the exercise at issue times
(B) the price at which the sell order giving rise to such purchase
obligation was executed, and (2) at the option of the Holder, either
reinstate the portion of the Warrant and equivalent number of shares
of Warrant Stock for which such exercise was not honored or deliver to
the Holder the number of shares of Common Stock that would have been
issued had the Issuer timely complied with its exercise and delivery
obligations hereunder.  For example, if the Holder purchases Common
Stock having a total purchase price of $11,000 to cover a Buy-In with
respect to an attempted exercise of shares of Common Stock with an
aggregate sale price giving rise to such purchase obligation of
$10,000, under clause (1) of the immediately preceding sentence the
Issuer shall be required to pay the Holder $1,000. The Holder shall
provide the Issuer written notice indicating the amounts payable to
the Holder in respect of the Buy-In, together with applicable
confirmations and other evidence reasonably requested by the Issuer.
Nothing herein shall limit a Holder's right to pursue any other
remedies available to it hereunder, at law or in equity including,
without limitation, a decree of specific performance and/or injunctive
relief with respect to the Issuer's failure to timely deliver
certificates representing shares of Common Stock upon exercise of this
Warrant as required pursuant to the terms hereof.

                               -3-
<PAGE>

    (f)  Transferability of Warrant.  Subject to Section 2(h)
         --------------------------
hereof, this Warrant may be transferred by a Holder, in whole or in
part, without the consent of the Issuer.  If transferred pursuant to
this paragraph, this Warrant may be transferred on the books of the
Issuer by the Holder hereof in person or by duly authorized attorney,
upon surrender of this Warrant at the principal office of the Issuer,
properly endorsed (by the Holder executing an assignment in the form
attached hereto) and upon payment of any necessary transfer tax or
other governmental charge imposed upon such transfer.  This Warrant is
exchangeable at the principal office of the Issuer for Warrants to
purchase the same aggregate number of shares of Warrant Stock, each
new Warrant to represent the right to purchase such number of shares
of Warrant Stock as the Holder hereof shall designate at the time of
such exchange.  All Warrants issued on transfers or exchanges shall be
dated the Original Issue Date and shall be identical with this Warrant
except as to the number of shares of Warrant Stock issuable pursuant
thereto.

    (g)  Continuing Rights of Holder.  The Issuer will, at the time
         ---------------------------
of or at any time after each exercise of this Warrant, upon the
request of the Holder hereof, acknowledge in writing the extent, if
any, of its continuing obligation to afford to such Holder all rights
to which such Holder shall continue to be entitled after such exercise
in accordance with the terms of this Warrant, provided that if any
such Holder shall fail to make any such request, the failure shall not
affect the continuing obligation of the Issuer to afford such rights
to such Holder.

    (h)  Compliance with Securities Laws.
         -------------------------------

         (i)     The Holder of this Warrant, by acceptance hereof,
acknowledges that this Warrant and the shares of Warrant Stock to
be issued upon exercise hereof are being acquired solely for the
Holder's own account and not as a nominee for any other party,
and for investment, and that the Holder will not offer, sell or
otherwise dispose of this Warrant or any shares of Warrant Stock
to be issued upon exercise hereof except pursuant to an effective
registration statement, or an exemption from registration, under
the Securities Act and any applicable state securities laws.

         (ii)    Except as provided in paragraph (iii) below, this
Warrant and all certificates representing shares of Warrant Stock
issued upon exercise hereof shall be stamped or imprinted with a
legend in substantially the following form:

         THIS WARRANT AND THE SHARES OF COMMON STOCK
         ISSUABLE UPON EXERCISE HEREOF HAVE NOT BEEN
         REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
         AMENDED (THE "SECURITIES ACT") OR ANY STATE
         SECURITIES LAWS AND MAY NOT BE SOLD, TRANSFERRED
         OR OTHERWISE DISPOSED OF UNLESS REGISTERED UNDER
         THE SECURITIES ACT AND UNDER APPLICABLE STATE
         SECURITIES LAWS OR THE ISSUER SHALL HAVE RECEIVED
         AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO
         THE ISSUER THAT REGISTRATION OF SUCH SECURITIES
         UNDER THE SECURITIES ACT AND UNDER THE PROVISIONS

                               -4-
<PAGE>

         OF APPLICABLE STATE SECURITIES LAWS IS NOT
         REQUIRED.

         (iii)   The Issuer agrees to reissue this Warrant or
certificates representing any of the Warrant Stock, without the
legend set forth above if at such time, prior to making any
transfer of any such securities, the Holder shall give written
notice to the Issuer describing the manner and terms of such
transfer.  Such proposed transfer will not be effected until: (a)
either (i) the Issuer has received an opinion of counsel
reasonably satisfactory to the Issuer, to the effect that the
registration of such securities under the Securities Act is not
required in connection with such proposed transfer, (ii) a
registration statement under the Securities Act covering such
proposed disposition has been filed by the Issuer with the
Securities and Exchange Commission and has become effective under
the Securities Act; provided however, that the Issuer has no
obligation or intent to register the Warrant, but shall register
the shares of Common Stock underlying the Warrants pursuant to
the terms of the Registration Rights Agreement (as defined in the
Purchase Agreement), (iii) the Issuer has received other evidence
reasonably satisfactory to the Issuer that such registration and
qualification under the Securities Act and state securities laws
are not required, or (iv) the Holder provides the Issuer with
reasonable assurances that such security can be sold pursuant to
Rule 144 under the Securities Act; and (b) either (i) the Issuer
has received an opinion of counsel reasonably satisfactory to the
Issuer, to the effect that registration or qualification under
the securities or "blue sky" laws of any state is not required in
connection with such proposed disposition, or (ii) compliance
with applicable state securities or "blue sky" laws has been
effected or a valid exemption exists with respect thereto.  The
Issuer will respond to any such notice from a holder within three
(3) Trading Days.  In the case of any proposed transfer under
this Section 2(h), the Issuer will use reasonable efforts to
comply with any such applicable state securities or "blue sky"
laws, but shall in no event be required, (x) to qualify to do
business in any state where it is not then qualified, (y) to take
any action that would subject it to tax or to the general service
of process in any state where it is not then subject, or (z) to
comply with state securities or "blue sky" laws of any state for
which registration by coordination is unavailable to the Issuer
or to register the Warrants under state securities laws.  The
restrictions on transfer contained in this Section 2(h) shall be
in addition to, and not by way of limitation of, any other
restrictions on transfer contained in any other section of this
Warrant.  Whenever a certificate representing the Warrant Stock
is required to be issued to a Holder without a legend, in lieu of
delivering physical certificates representing the Warrant Stock,
the Issuer shall cause its transfer agent to electronically
transmit the Warrant Stock to the Holder by crediting the account
of the Holder or Holder's Prime Broker with DTC through its DWAC
system (to the extent not inconsistent with any provisions of
this Warrant or the Purchase Agreement).

         (i)     Accredited Investor Status.  In no event may the
                 --------------------------
Holder exercise this Warrant in whole or in part unless the Holder
is an "accredited investor" as defined in Regulation D under the
Securities Act.

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<PAGE>

    3.   Stock Fully Paid; Reservation and Listing of Shares;
         ----------------------------------------------------
Covenants.
---------

    (a)  Stock Fully Paid.  The Issuer represents, warrants,
         ----------------
covenants and agrees that all shares of Warrant Stock which may be
issued upon the exercise of this Warrant or otherwise hereunder will,
when issued in accordance with the terms of this Warrant, be duly
authorized, validly issued, fully paid and non-assessable and free
from all taxes, liens and charges created by or through the Issuer.
The Issuer further covenants and agrees that during the period within
which this Warrant may be exercised, the Issuer will at all times have
authorized and reserved for the purpose of the issuance upon exercise
of this Warrant a number of authorized but unissued shares of Common
Stock equal to at least one hundred fifty (150%) of the number of
shares of Common Stock issuable upon exercise of this Warrant without
regard to any limitations on exercise.

    (b)  Reservation.  If any shares of Common Stock required to be
         -----------
reserved for issuance upon exercise of this Warrant or as otherwise
provided hereunder require registration or qualification with any
Governmental Authority under any federal or state law before such
shares may be so issued, the Issuer will in good faith use its best
efforts as expeditiously as possible at its expense to cause such
shares to be duly registered or qualified.  If the Issuer shall list
any shares of Common Stock on any securities exchange or market it
will, at its expense, list thereon, and maintain and increase when
necessary such listing, of, all shares of Warrant Stock from time to
time issued upon exercise of this Warrant or as otherwise provided
hereunder (provided that such Warrant Stock has been registered
pursuant to a registration statement under the Securities Act then in
effect), and, to the extent permissible under the applicable
securities exchange rules, all unissued shares of Warrant Stock which
are at any time issuable hereunder, so long as any shares of Common
Stock shall be so listed.  The Issuer will also so list on each
securities exchange or market, and will maintain such listing of, any
other securities which the Holder of this Warrant shall be entitled to
receive upon the exercise of this Warrant if at the time any
securities of the same class shall be listed on such securities
exchange or market by the Issuer.

    (c)  Covenants.  The Issuer shall not by any action including,
         ---------
without limitation, amending the Articles of Incorporation or the by-
laws of the Issuer, or through any reorganization, transfer of assets,
consolidation, merger, dissolution, issue or sale of securities or any
other action, avoid or seek to avoid the observance or performance of
any of the terms of this Warrant, but will at all times in good faith
assist in the carrying out of all such terms and in the taking of all
such actions as may be necessary or appropriate to protect the rights
of the Holder hereof against dilution (to the extent specifically
provided herein) or impairment.  Without limiting the generality of
the foregoing, the Issuer will (i) not permit the par value, if any,
of its Common Stock to exceed the then effective Warrant Price, (ii)
not amend or modify any provision of the Articles of Incorporation or
by-laws of the Issuer in any manner that would adversely affect the
rights of the Holders of the Warrants, (iii) take all such action as
may be reasonably necessary in order that the Issuer may validly and
legally issue fully paid and nonassessable shares of Common Stock,
free and clear of any liens, claims, encumbrances and restrictions
(other than as provided herein) upon the exercise of this Warrant, and
(iv) use its best efforts to obtain all such authorizations,
exemptions or consents from any public regulatory body having

                               -6-
<PAGE>

jurisdiction thereof as may be reasonably necessary to enable the
Issuer to perform its obligations under this Warrant.

    (d)  Loss, Theft, Destruction of Warrants.  Upon receipt of
         ------------------------------------
evidence satisfactory to the Issuer of the ownership of and the loss,
theft, destruction or mutilation of any Warrant and, in the case of
any such loss, theft or destruction, upon receipt of indemnity or
security satisfactory to the Issuer or, in the case of any such
mutilation, upon surrender and cancellation of such Warrant, the
Issuer will make and deliver, in lieu of such lost, stolen, destroyed
or mutilated Warrant, a new Warrant of like tenor and representing the
right to purchase the same number of shares of Common Stock.

    (e)  Payment of Taxes.  The Issuer will pay any documentary
         ----------------
stamp taxes attributable to the initial issuance of the Warrant Stock
issuable upon exercise of this Warrant; provided, however, that the
Issuer shall not be required to pay any tax or taxes which may be
payable in respect of any transfer involved in the issuance or
delivery of any certificates representing Warrant Stock in a name
other than that of the Holder in respect to which such shares are
issued.

    4.   Adjustment of Warrant Price.  The price at which such
         ---------------------------
shares of Warrant Stock may be purchased upon exercise of this Warrant
shall be subject to adjustment from time to time as set forth in this
Section 4. The Issuer shall give the Holder notice of any event
described below which requires an adjustment pursuant to this Section
4 in accordance with the notice provisions set forth in Section 5.

    (a)  Recapitalization, Reorganization, Reclassification,
         ---------------------------------------------------
Consolidation, Merger or Sale.
-----------------------------

	(i)  In case the Issuer after the Original Issue Date shall
do any of the following (each, a "Triggering Event"): (a)
consolidate or merge with or into any other Person and the Issuer
shall not be the continuing or surviving corporation of such
consolidation or merger (except for the Merger (as defined in
subsection (c) below), or any future strategic acquisitions,
which are approved in writing by the Holder, such approval not to
be unreasonably withheld (each a "Permitted Future
Transaction")), or (b) permit any other Person to consolidate
with or merge into the Issuer and the Issuer shall be the
continuing or surviving Person but, in connection with such
consolidation or merger (except for the Merger, or a Permitted
Future Transaction), any Capital Stock of the Issuer shall be
changed into or exchanged for Securities of any other Person or
cash or any other property, or (c) transfer all or substantially
all of its properties or assets to any other Person, or (d)
effect a capital reorganization or reclassification of its
Capital Stock, then, and in the case of each such Triggering
Event, proper provision shall be made to the Warrant Price and
the number of shares of Warrant Stock that may be purchased upon
exercise of this Warrant so that, upon the basis and the terms
and in the manner provided in this Warrant, the Holder of this
Warrant shall be entitled upon the exercise hereof at any time
after the consummation of such Triggering Event, to the extent
this Warrant is not exercised prior to such Triggering Event, to
receive at the Warrant Price as adjusted to take into account the
consummation of such Triggering Event, in lieu of the Common
Stock issuable upon such exercise of this Warrant prior to such
Triggering Event or any securities that this Warrant would
entitle the Holder to offer the Triggering Event were it not for

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<PAGE>

this provision, the Securities, cash and property to which such
Holder would have been entitled upon the consummation of such
Triggering Event if such Holder had exercised the rights
represented by this Warrant immediately prior thereto (including
the right of a shareholder to elect the type of consideration it
will receive upon a Triggering Event), subject to adjustments
(subsequent to such corporate action) as nearly equivalent as
possible to the adjustments provided for elsewhere in this
Section 4; provided, however, the Holder at its option may elect
to receive instead an amount in cash equal to the value of this
Warrant calculated in accordance with the Black-Scholes formula.
Immediately upon the occurrence of a Triggering Event, the Issuer
shall notify the Holder in writing of such Triggering Event and
provide the calculations in determining the number of shares of
Warrant Stock issuable upon exercise of the new warrant and the
adjusted Warrant Price.  Upon the Holder's request, in lieu of
receiving cash or other property as set out above, the continuing
or surviving corporation as a result of such Triggering Event
shall issue to the Holder a new warrant of like tenor evidencing
the right to purchase the adjusted number of shares of Warrant
Stock and the adjusted Warrant Price pursuant to the terms and
provisions of this Section 4(a)(i).  Notwithstanding the
foregoing to the contrary, this Section 4(a)(i) shall only apply
if the surviving entity pursuant to any such Triggering Event is
a company that has a class of equity securities registered
pursuant to the Securities Exchange Act of 1934, as amended, and
its common stock is listed or quoted on a national securities
exchange, national automated quotation system or the OTC Bulletin
Board.  In the event that the surviving entity pursuant to any
such Triggering Event is not a public company that is registered
pursuant to the Securities Exchange Act of 1934, as amended, or
its common stock is not listed or quoted on a national securities
exchange, national automated quotation system or the OTC Bulletin
Board, then the Holder shall have the right to demand that the
Issuer pay to the Holder an amount in cash equal to the value of
this Warrant calculated in accordance with the Black-Scholes
formula in exchange for termination of this Warrant.

         (ii)    In the event that the Holder has elected not to
exercise this Warrant prior to the consummation of a Triggering
Event and has also elected not to receive an amount in cash equal
to the value of this Warrant calculated in accordance with the
Black-Scholes formula pursuant to the provisions of Section
4(a)(i) above, so long as the surviving entity pursuant to any
Triggering Event is a company that has a class of equity
securities registered pursuant to the Securities Exchange Act of
1934, as amended, and its common stock is listed or quoted on a
national securities exchange, national automated quotation system
or the OTC Bulletin Board, the surviving entity and/or each
Person (other than the Issuer) which may be required to deliver
any Securities, cash or property upon the exercise of this
Warrant as provided herein shall assume, by written instrument
delivered to, and reasonably satisfactory to, the Holder of this
Warrant, (A) the obligations of the Issuer under this Warrant
(and if the Issuer shall survive the consummation of such
Triggering Event, such assumption shall be in addition to, and
shall not release the Issuer from, any continuing obligations of
the Issuer under this Warrant) if the Holders does not elect to
receive cash or securities under Section 4(a)(i) or (B) the
obligation to deliver to such Holder such Securities, cash or
property as, in accordance with the foregoing provisions of this
subsection (a), and such Holder shall be entitled to receive a
written acknowledgement executed by the President or Chief

                               -8-
<PAGE>

Financial Officer of the Issuer, stating that this Warrant shall
thereafter continue in full force and effect and the terms hereof
(including, without limitation, all of the provisions of this
subsection (a) shall be applicable to the Securities, cash or
property which the surviving entity and/or each such Person may
be required to deliver upon any exercise of this Warrant or the
exercise of any rights pursuant hereto.

    (b)  Stock Dividends, Subdivisions and Combinations.  If at
         ----------------------------------------------
any time the Issuer shall:

         (i)     make or issue or set a record date for the
holders of the Common Stock for the purpose of entitling them to
receive a dividend payable in, or other distribution of, shares
of Common Stock,

         (ii)    subdivide its outstanding shares of Common Stock
into a larger number of shares of Common Stock, or

         (iii)   combine its outstanding shares of Common
Stock into a smaller number of shares of Common Stock,

then (1) the number of shares of Common Stock for which this Warrant
is exercisable immediately after the occurrence of any such event
shall be adjusted to equal the number of shares of Common Stock which
a record holder of the same number of shares of Common Stock for which
this Warrant is exercisable immediately prior to the occurrence of
such event would own or be entitled to receive after the happening of
such event, and (2) the Warrant Price then in effect shall be adjusted
to equal (A) the Warrant Price then in effect multiplied by the number
of shares of Common Stock for which this Warrant is exercisable
immediately prior to the adjustment divided by (B) the number of
shares of Common Stock for which this Warrant is exercisable
immediately after such adjustment.

    (c)  Certain Other Distributions.  If at any time the Issuer
         ---------------------------
shall make or issue or set a record date for the holders of the Common
Stock for the purpose of entitling them to receive any dividend or
other distribution of:

         (i)     cash,

         (ii)    any evidences of its indebtedness, any shares of
stock of any class or any other securities or property of any
nature whatsoever (other than cash, Common Stock Equivalents or
Additional Shares of Common Stock), or

         (iii)   any warrants or other rights to subscribe for or
purchase any evidences of its indebtedness, any shares of stock
of any class or any other securities or property of any nature
whatsoever (other than cash, Common Stock Equivalents or
Additional Shares of Common Stock),

then (1) the number of shares of Common Stock for which this Warrant
is exercisable shall be adjusted to equal the product of the number of
shares of Common Stock for which this Warrant is exercisable

                               -9-
<PAGE>

immediately prior to such adjustment multiplied by a fraction (A) the
numerator of which shall be the Per Share Market Value of Common Stock
at the date of taking such record and (B) the denominator of which
shall be such Per Share Market Value minus the amount allocable to one
share of Common Stock of any such cash so distributable and of the
fair value (as determined in good faith by the Board of Directors of
the Issuer and supported by an opinion from an investment banking firm
mutually agreed upon by the Issuer and the Holder) of any and all such
evidences of indebtedness, shares of stock, other securities or
property or warrants or other subscription or purchase rights so
distributable, and (2) the Warrant Price then in effect shall be
adjusted to equal (A) the Warrant Price then in effect multiplied by
the number of shares of Common Stock for which this Warrant is
exercisable immediately prior to the adjustment divided by (B) the
number of shares of Common Stock for which this Warrant is exercisable
immediately after such adjustment.  A reclassification of the Common
Stock (other than a change in par value, or from par value to no par
value or from no par value to par value) into shares of Common Stock
and shares of any other class of stock shall be deemed a distribution
by the Issuer to the holders of its Common Stock of such shares of
such other class of stock within the meaning of this Section 4(c) and,
if the outstanding shares of Common Stock shall be changed into a
larger or smaller number of shares of Common Stock as a part of such
reclassification, such change shall be deemed a subdivision or
combination, as the case may be, of the outstanding shares of Common
Stock within the meaning of Section 4(b).  This Section 4(c) shall not
apply to the issuance by the Company of (i) warrants for up to
3,000,000 shares of Common Stock of the Company in connection with an
employee stock option program (an "ESOP") to be established concurrent
with closing of the merger between Medpro Safety Products, Inc.
("Medpro") and the Company (the "Merger"), priced at $1.81 per share,
to be issued to the current management of Medpro and the future
management of the Company (the "ESOP Warrants"), and (ii) 68,036
warrants, priced at $1.99, to be issued to Chrystal Research (the
"Chrystal Research Warrants").

    (d)  Issuance of Additional Shares of Common Stock.  For a
         ---------------------------------------------
period of twelve (12) months after the Issuance Date, as defined
below (the "Price Protection Period"), in the event the Company shall
issue or sell any additional shares of Common Stock (otherwise than as
provided herein or pursuant to Common Stock Equivalents (hereafter
defined) granted or issued prior to the Issuance Date) (the
"Additional Shares of Common Stock"), at a price per share ("New
Price") less than the conversion price of the Series A Preferred Stock
of the Issuer (the "Conversion Price") then in effect ("Down Round"),
or without consideration, the Conversion Price shall be reduced
concurrently with such issue to the New Price.  The "Issuance Date"
shall be defined as the date of the issuance of the Series A Preferred
Stock of the Issuer to the Holder, or August 20, 2007.  After the
Price Protection Period, the Conversion Price shall be reset to the
Conversion Price in effect immediately prior to the Down Round, and
thereafter, for so long as the Series A Preferred Stock has not been
converted into Common Stock, but only for a period of twelve (12)
months, the Conversion Price then in effect upon each issuance of a
Down Round shall be adjusted to that price (rounded to the nearest
cent) determined by multiplying the Conversion Price by a fraction:

         1)      the numerator of which shall be equal to
the sum of (A) the number of shares of Common Stock outstanding
immediately prior to the issuance of such Additional Shares of Common
Stock plus (B) the number of shares of Common Stock (rounded to the

                               -10-
<PAGE>

nearest whole share) which the aggregate consideration for the total
number of such Additional Shares of Common Stock so issued would
purchase at a price per share equal to the then Conversion Price, and

         2)      the denominator of which shall be equal to
the number of shares of Common Stock outstanding immediately after the
issuance of such Additional Shares of Common Stock.  This Section
4(d)(2) and the adjustments described herein shall not apply to (i)
the issuance of Common Stock pursuant to the agency agreement between
SGPF, LLC and Medpro, in connection with the Merger, (ii) a Permitted
Future Transaction, (iii) the ESOP Warrants, or (iv) the Chrystal
Research Warrants.

    (e)  Issuance of Common Stock Equivalents.  In the event the
         ------------------------------------
Issuer shall at any time following the Original Issuance Date take a
record of the holders of its Common Stock for the purpose of entitling
them to receive a distribution of, or shall in any manner (whether
directly or by assumption in a merger in which the Issuer is the
surviving corporation) issue or sell, any Common Stock Equivalents,
whether or not the rights to exchange or convert thereunder are
immediately exercisable, and the price per share for which Common
Stock is issuable upon such conversion or exchange shall be less than
the Warrant Price in effect immediately prior to the time of such
issue or sale, or if, after any such issuance of Common Stock
Equivalents, the price per share for which Additional Shares of Common
Stock may be issuable thereafter is amended or adjusted, and such
price as so amended shall be less than the Warrant Price in effect at
the time of such amendment or adjustment, then the Warrant Price then
in effect shall be adjusted as provided in Section 4(d).  No further
adjustments of the number of shares of Common Stock for which this
Warrant is exercisable and the Warrant Price then in effect shall be
made upon the actual issue of such Common Stock upon conversion or
exchange of such Common Stock Equivalents.  This Section 4(e) shall
not apply to the issuance of (i) the ESOP Warrants, or (ii) the
Chrystal Research Warrants.

    (f)  Other Provisions applicable to Adjustments under this
         -----------------------------------------------------
Section.  The following provisions shall be applicable to the making
-------
of adjustments of the number of shares of Common Stock for which this
Warrant is exercisable and the Warrant Price then in effect provided
for in this Section 4:

         (i)     Computation of Consideration.  To the extent that any
                 ----------------------------
Additional Shares of Common Stock or any Common Stock Equivalents (or
any warrants or other rights therefor) shall be issued for cash
consideration, the consideration received by the Issuer therefor shall
be the amount of the cash received by the Issuer therefor, or, if such
Additional Shares of Common Stock or Common Stock Equivalents are
offered by the Issuer for subscription, the subscription price, or, if
such Additional Shares of Common Stock or Common Stock Equivalents are
sold to underwriters or dealers for public offering without a
subscription offering, the initial public offering price (in any such
case subtracting any amounts paid or receivable for accrued interest
or accrued dividends and without taking into account any compensation,
discounts or expenses paid or incurred by the Issuer for and in the
underwriting of, or otherwise in connection with, the issuance
thereof).  In connection with any merger or consolidation in which the
Issuer is the surviving corporation (other than any consolidation or
merger in which the previously outstanding shares of Common Stock of
the Issuer shall be changed to or exchanged for the stock or other
securities of another corporation), the amount of consideration
therefore shall be, deemed to be the fair market value, as determined

                               -11-
<PAGE>

reasonably and in good faith by the Board, of such portion of the
assets and business of the nonsurviving corporation as the Board may
determine to be attributable to such shares of Common Stock or Common
Stock Equivalents, as the case may be.  The consideration for any
Additional Shares of Common Stock issuable pursuant to any warrants or
other rights to subscribe for or purchase the same shall be the
consideration received by the Issuer for issuing such warrants or
other rights plus the additional consideration payable to the Issuer
upon exercise of such warrants or other rights.  The consideration for
any Additional Shares of Common Stock issuable pursuant to the terms
of any Common Stock Equivalents shall be the consideration received by
the Issuer for issuing warrants or other rights to subscribe for or
purchase such Common Stock Equivalents, plus the consideration paid or
payable to the Issuer in respect of the subscription for or purchase
of such Common Stock Equivalents, plus the additional consideration,
if any, payable to the Issuer upon the exercise of the right of
conversion or exchange in such Common Stock Equivalents.  In the event
of any consolidation or merger of the Issuer in which the Issuer is
not the surviving corporation or in which the previously outstanding
shares of Common Stock of the Issuer shall be changed into or
exchanged for the stock or other securities of another corporation, or
in the event of any sale of all or substantially all of the assets of
the Issuer for stock or other securities of any corporation, the
Issuer shall be deemed to have issued a number of shares of its Common
Stock for stock or securities or other property of the other
corporation computed on the basis of the actual exchange ratio on
which the transaction was predicated, and for a consideration equal to
the fair market value on the date of such transaction of all such
stock or securities or other property of the other corporation.  In
the event any consideration received by the Issuer for any securities
consists of property other than cash, the fair market value thereof at
the time of issuance or as otherwise applicable shall be as determined
in good faith by the Board.  In the event Common Stock is issued with
other shares or securities or other assets of the Issuer for
consideration which covers both, the consideration computed as
provided in this Section 4(f)(i) shall be allocated among such
securities and assets as determined in good faith by the Board.

         (ii)    When Adjustments to Be Made.  The adjustments required
                 ---------------------------
by this Section 4 shall be made whenever and as often as any specified
event requiring an adjustment shall occur, except that any adjustment
of the number of shares of Common Stock for which this Warrant is
exercisable that would otherwise be required may be postponed (except
in the case of a subdivision or combination of shares of the Common
Stock, as provided for in Section 4(b)) up to, but not beyond the date
of exercise if such adjustment either by itself or with other
adjustments not previously made adds or subtracts less than one
percent (1%) of the shares of Common Stock for which this Warrant is
exercisable immediately prior to the making of such adjustment.  Any
adjustment representing a change of less than such minimum amount
(except as aforesaid) which is postponed shall be carried forward and
made as soon as such adjustment, together with other adjustments
required by this Section 4 and not previously made, would result in a
minimum adjustment or on the date of exercise. For the purpose of any
adjustment, any specified event shall be deemed to have occurred at
the close of business on the date of its occurrence.

         (iii)   Fractional Interests.  In computing adjustments under
                 --------------------
this Section 4, fractional interests in Common Stock shall be taken
into account to the nearest one one-hundredth (1/100th) of a share.

                               -12-
<PAGE>

         (iv)    When Adjustment Not Required.  If the Issuer shall
                 ----------------------------
take a record of the holders of its Common Stock for the purpose of
entitling them to receive a dividend or distribution or subscription
or purchase rights and shall, thereafter and before the distribution
to stockholders thereof, legally abandon its plan to pay or deliver
such dividend, distribution, subscription or purchase rights, then
thereafter no adjustment shall be required by reason of the taking of
such record and any such adjustment previously made in respect thereof
shall be rescinded and annulled.

    (g)  Form of Warrant after Adjustments.  The form of this
         ---------------------------------
Warrant need not be changed because of any adjustments in the Warrant
Price or the number and kind of Securities purchasable upon the
exercise of this Warrant.

    (h)  Escrow of Warrant Stock.  If after any property becomes
         -----------------------
distributable pursuant to this Section 4 by reason of the taking of
any record of the holders of Common Stock, but prior to the occurrence
of the event for which such record is taken, and the Holder exercises
this Warrant, any shares of Common Stock issuable upon exercise by
reason of such adjustment shall be deemed the last shares of Common
Stock for which this Warrant is exercised (notwithstanding any other
provision to the contrary herein) and such shares or other property
shall be held in escrow for the Holder by the Issuer to be issued to
the Holder upon and to the extent that the event actually takes place,
upon payment of the current Warrant Price.  Notwithstanding any other
provision to the contrary herein, if the event for which such record
was taken fails to occur or is rescinded, then such escrowed shares
shall be cancelled by the Issuer and escrowed property returned.

    5.   Notice of Adjustments.  Whenever the Warrant Price or
         ---------------------
Warrant Share Number shall be adjusted pursuant to Section 4 hereof
(for purposes of this Section 5, each an "adjustment"), the Issuer
shall cause its Chief Financial Officer to prepare and execute a
certificate setting forth, in reasonable detail, the event requiring
the adjustment, the amount of the adjustment, the method by which such
adjustment was calculated (including a description of the basis on
which the Board made any determination hereunder), and the Warrant
Price and Warrant Share Number after giving effect to such adjustment,
and shall cause copies of such certificate to be delivered to the
Holder of this Warrant promptly after each adjustment.  Any dispute
between the Issuer and the Holder of this Warrant with respect to the
matters set forth in such certificate may at the option of the Holder
of this Warrant be submitted to a national or regional accounting firm
reasonably acceptable to the Issuer and the Holder, provided that the
Issuer shall have ten (10) days after receipt of notice from such
Holder of its selection of such firm to object thereto, in which case
such Holder shall select another such firm and the Issuer shall have
no such right of objection.  The firm selected by the Holder of this
Warrant as provided in the preceding sentence shall be instructed to
deliver a written opinion as to such matters to the Issuer and such
Holder within thirty (30) days after submission to it of such dispute.
Such opinion shall be final and binding on the parties hereto.  The
costs and expenses of the initial accounting firm shall be paid
equally by the Issuer and the Holder and, in the case of an objection
by the Issuer, the costs and expenses of the subsequent accounting
firm shall be paid in full by the Issuer.

                               -13-
<PAGE>

    6.   Fractional Shares.  No fractional shares of Warrant Stock
         -----------------
will be issued in connection with any exercise hereof, but in lieu of
such fractional shares, the Issuer shall round the number of shares to
be issued upon exercise up to the nearest whole number of shares.

    7.   Ownership Cap and Exercise Restriction.  Notwithstanding
         --------------------------------------
anything to the contrary set forth in this Warrant, at no time may a
Holder of this Warrant exercise this Warrant if the number of shares
of Common Stock to be issued pursuant to such exercise would exceed,
when aggregated with all other shares of Common Stock owned by such
Holder at such time, the number of shares of Common Stock which would
result in such Holder beneficially owning (as determined in accordance
with Section 13(d) of the Exchange Act and the rules  thereunder) in
excess of 4.9% of the then issued and outstanding shares of Common
Stock; provided, however, that upon a holder of this Warrant providing
the Issuer with sixty-one (61) days notice (pursuant to Section 13
hereof) (the "Waiver Notice") that such Holder would like to waive
this Section 7 with regard to any or all shares of Common Stock
issuable upon exercise of this Warrant, this Section 7 will be of no
force or effect with regard to all or a portion of the Warrant
referenced in the Waiver Notice; provided, further, that this
provision shall be of no further force or effect during the sixty-one
(61) days immediately preceding the expiration of the term of this
Warrant.

    8.   Definitions.  For the purposes of this Warrant, the
         -----------
following terms have the following meanings:

         "Additional Shares of Common Stock" means all shares of
          ---------------------------------
     Common Stock issued by the Issuer after the Original Issue Date,
     and all shares of Other Common, if any, issued by the Issuer
     after the Original Issue Date, except: (i) securities issued
     (other than for cash) in connection with a merger, acquisition,
     or consolidation, (ii) securities issued pursuant to the
     conversion or exercise of convertible or exercisable securities
     issued or outstanding on or prior to the date of the Purchase
     Agreement or issued pursuant to the Purchase Agreement or
     otherwise excepted herein (so long as the conversion or exercise
     price in such securities are not amended to lower such price
     and/or adversely affect the Holders), (iii) the Warrant Stock,
     (iv) securities issued in connection with bona fide strategic
     license agreements or other partnering arrangements so long as
     such issuances are not for the purpose of raising capital, (v)
     Common Stock issued or the issuance or grants of options to
     purchase Common Stock pursuant to the Issuer's stock option plans
     and employee stock purchase plans outstanding as they exist on
     the date of the Purchase Agreement, (vi) any warrants issued to
     the placement agent and its designees or to the Company's
     investor relations firm for the transactions contemplated by the
     Purchase Agreement, and (vii) Common Stock issued by Issuer in
     connection with Medpro's  agency agreement with SGPF, LLC, which
     is contemplated in connection with the Merger.

         "Articles of Incorporation" means the Articles of
          -------------------------
     Incorporation of the Issuer as in effect on the Original Issue
     Date, and as hereafter from time to time amended, modified,
     supplemented or restated in accordance with the terms hereof and
     thereof and pursuant to applicable law.

         "Board" shall mean the Board of Directors of the Issuer.
          -----

                               -14-
<PAGE>

         "Capital Stock" means and includes (i) any and all shares,
          -------------
     interests, participations or other equivalents of or interests in
     (however designated) corporate stock, including, without
     limitation, shares of preferred or preference stock, (ii) all
     partnership interests (whether general or limited) in any Person
     which is a partnership, (iii) all membership interests or limited
     liability company interests in any limited liability company, and
     (iv) all equity or ownership interests in any Person of any other
     type.

         "Common Stock" means the Common Stock, $0.01 par value per
          ------------
     share, of the Issuer and any other Capital Stock into which such
     stock may hereafter be changed.

         "Common Stock Equivalent" means any Convertible Security or
          -----------------------
     warrant, option or other right to subscribe for or purchase any
     Additional Shares of Common Stock or any Convertible Security.

         "Convertible Securities" means evidences of Indebtedness,
          ----------------------
     shares of Capital Stock or other Securities which are or may be
     at any time convertible into or exchangeable for Additional
     Shares of Common Stock.  The term "Convertible Security" means
     one of the Convertible Securities.

         "Governmental Authority" means any governmental, regulatory
          ----------------------
     or self-regulatory entity, department, body, official, authority,
     commission, board, agency or instrumentality, whether federal,
     state or local, and whether domestic or foreign.

         "Holders" mean the Persons who shall from time to time own
          -------
     any Warrant.  The term "Holder" means one of the Holders.

         "Independent Appraiser" means a nationally recognized or
          ---------------------
     major regional investment banking firm or firm of independent
     certified public accountants of recognized standing (which may be
     the firm that regularly examines the financial statements of the
     Issuer) that is regularly engaged in the business of appraising
     the Capital Stock or assets of corporations or other entities as
     going concerns, and which is not affiliated with either the
     Issuer or the Holder of any Warrant.

         "Issuer" means Dentalserv.com, a Nevada corporation, and
          ------
     its successors.

         "Majority Holders" means at any time the Holders of
          ----------------
     Warrants exercisable for a majority of the shares of Warrant
     Stock issuable under the Warrants at the time outstanding.

         "Original Issue Date" means August 20, 2007.
          -------------------

         "OTC Bulletin Board" means the over-the-counter electronic
          ------------------
     bulletin board.

         "Other Common" means any other Capital Stock of the Issuer
          ------------
     of any class which shall be authorized at any time after the date

                               -15-
<PAGE>

     of this Warrant (other than Common Stock) and which shall have
     the right to participate in the distribution of earnings and
     assets of the Issuer without limitation as to amount.

         "Outstanding Common Stock" means, at any given time, the
          ------------------------
     aggregate amount of outstanding shares of Common Stock, assuming
     full exercise, conversion or exchange (as applicable) of all
     options, warrants and other Securities which are convertible into
     or exercisable or exchangeable for, and any right to subscribe
     for, shares of Common Stock that are outstanding at such time.

         "Person" means an individual, corporation, limited
          ------
     liability company, partnership, joint stock company, trust,
     unincorporated organization, joint venture, Governmental
     Authority or other entity of whatever nature.

         "Per Share Market Value" means on any particular date (a)
          ----------------------
     the last closing bid price per share of the Common Stock on such
     date on the OTC Bulletin Board or a registered national stock
     exchange on which the Common Stock is then listed, or if there is
     no such price on such date, then the closing price on such
     exchange or quotation system on the date nearest preceding such
     date, or (b) if the Common Stock is not listed or traded then on
     the OTC Bulletin Board or any registered national stock exchange,
     the last closing bid price for a share of Common Stock in the
     over-the-counter market, as reported by the OTC Bulletin Board or
     by the Pink Sheets LLC or similar organization or agency
     succeeding to its functions of reporting prices) at the close of
     business on such date, or (c) if the Common Stock is not then
     publicly traded the fair market value of a share of Common Stock
     as determined by an Independent Appraiser selected in good faith
     by the Majority Holders; provided, however, that the Issuer,
     after receipt of the determination by such Independent Appraiser,
     shall have the right to select an additional Independent
     Appraiser, in which case, the fair market value shall be equal to
     the average of the determinations by each such Independent
     Appraiser; and provided, further that all determinations of the
     Per Share Market Value shall be appropriately adjusted for any
     stock dividends, stock splits or other similar transactions
     during such period.  The determination of fair market value by an
     Independent Appraiser shall be based upon the fair market value
     of the Issuer determined on a going concern basis as between a
     willing buyer and a willing seller and taking into account all
     relevant factors determinative of value, and shall be final and
     binding on all parties.  In determining the fair market value of
     any shares of Common Stock, no consideration shall be given to
     any restrictions on transfer of the Common Stock imposed by
     agreement or by federal or state securities laws, or to the
     existence or absence of, or any limitations on, voting rights.

         "Purchase Agreement" means the Series C Convertible
          ------------------
     Preferred Stock Purchase Agreement dated as of August 20, 2007,
     among the Issuer and the Purchasers.

         "Purchasers" means the purchasers of the Series C
          ----------
     Convertible Preferred Stock and the Warrants issued by the Issuer
     pursuant to the Purchase Agreement.

         "Securities" means any debt or equity securities of the
          ----------
     Issuer, whether now or hereafter authorized, any instrument
     convertible into or exchangeable for Securities or a Security,
     and any option, warrant or other right to purchase or acquire any

                               -16-
<PAGE>

     Security.  "Security" means one of the Securities.

         "Securities Act" means the Securities Act of 1933, as
          --------------
     amended, or any similar federal statute then in effect.

         "Subsidiary" means any corporation at least 50% of whose
          ----------
     outstanding Voting Stock shall at the time be owned directly or
     indirectly by the Issuer or by one or more of its Subsidiaries,
     or by the Issuer and one or more of its Subsidiaries.

         "Term" has the meaning specified in Section 1 hereof.
          ----

         "Trading Day" means (a) a day on which the Common Stock is
          -----------
     traded on the OTC Bulletin Board or any other exchange or trading
     venue on which the Common Stock may be principally traded in the
     future, or (b) if the Common Stock is not traded on the OTC
     Bulletin Board, a day on which the Common Stock is quoted in the
     over-the-counter market as reported by the Pink Sheets LLC (or
     any similar organization or agency succeeding its functions of
     reporting prices); provided, however, that in the event that the
     Common Stock is not listed or quoted as set forth in (a) or (b)
     hereof, then Trading Day shall mean any day except Saturday,
     Sunday and any day which shall be a legal holiday or a day on
     which banking institutions in the State of New York are
     authorized or required by law or other government action to
     close.

         "Voting Stock" means, as applied to the Capital Stock of
          ------------
     any corporation, Capital Stock of any class or classes (however
     designated) having ordinary voting power for the election of a
     majority of the members of the Board of Directors (or other
     governing body) of such corporation, other than Capital Stock
     having such power only by reason of the happening of a
     contingency.

         "Warrants" means the Warrants issued and sold pursuant to
          --------
     the Purchase Agreement, including, without limitation, this
     Warrant, and any other warrants of like tenor issued in
     substitution or exchange for any thereof pursuant to the
     provisions of Section 2(c), 2(d) or 2(e) hereof or of any of such
     other Warrants.

         "Warrant Price" initially means $2.18, as such price may be
          -------------
     adjusted from time to time as shall result from the adjustments
     specified in this Warrant, including Section 4 hereto.

         "Warrant Share Number" means at any time the aggregate
          --------------------
     number of shares of Warrant Stock which may at such time be
     purchased upon exercise of this Warrant, after giving effect to
     all prior adjustments and increases to such number made or
     required to be made under the terms hereof.

         "Warrant Stock" means Common Stock issuable upon exercise
          -------------
     of any Warrant or Warrants or otherwise issuable pursuant to any
     Warrant or Warrants.

                               -17-
<PAGE>

    9.   Other Notices.  In case at any time:
         -------------

         (A)     the Issuer shall make any distributions to
                 the holders of Common Stock; or

         (B)     the Issuer shall authorize the granting to
                 all holders of its Common Stock of rights
                 to subscribe for or purchase any shares of
                 Capital Stock of any class or other rights;
                 or

         (C)     there shall be any reclassification of the
                 Capital Stock of the Issuer; or

         (D)     there shall be any capital reorganization
                 by the Issuer; or

         (E)     there shall be any (i) consolidation or
                 merger involving the Issuer or (ii) sale,
                 transfer or other disposition of all or
                 substantially all of the Issuer's property,
                 assets or business (except a merger or
                 other reorganization in which the Issuer
                 shall be the surviving corporation and its
                 shares of Capital Stock shall continue to
                 be outstanding and unchanged and except a
                 consolidation, merger, sale, transfer or
                 other disposition involving a wholly-owned
                 Subsidiary); or

         (F)     there shall be a voluntary or involuntary
                 dissolution, liquidation or winding-up of
                 the Issuer or any partial liquidation of
                 the Issuer or distribution to holders of
                 Common Stock;

then, in each of such cases, the Issuer shall give written notice to
the Holder of the date on which (i) the books of the Issuer shall
close or a record shall be taken for such dividend, distribution or
subscription rights or (ii) such reorganization, reclassification,
consolidation, merger, disposition, dissolution, liquidation or
winding-up, as the case may be, shall take place.  Such notice also
shall specify the date as of which the holders of Common Stock of
record shall participate in such dividend, distribution or
subscription rights, or shall be entitled to exchange their
certificates for Common Stock for securities or other property
deliverable upon such reorganization, reclassification, consolidation,
merger, disposition, dissolution, liquidation or winding-up, as the
case may be.  Such notice shall be given at least twenty (20) days
prior to the action in question and not less than ten (10) days prior
to the record date or the date on which the Issuer's transfer books
are closed in respect thereto.  This Warrant entitles the Holder to
receive copies of all financial and other information distributed or
required to be distributed to the holders of the Common Stock.

    10.  Amendment and Waiver.  Any term, covenant, agreement or
         --------------------
condition in this Warrant may be amended, or compliance therewith may
be waived (either generally or in a particular instance and either
retroactively or prospectively), by a written instrument or written
instruments executed by the Issuer and the Majority Holders; provided,

                               -18-
<PAGE>

however, that no such amendment or waiver shall reduce the Warrant
Share Number, increase the Warrant Price, shorten the period during
which this Warrant may be exercised or modify any provision of this
Section 11 without the consent of the Holder of this Warrant.  No
consideration shall be offered or paid to any person to amend or
consent to a waiver or modification of any provision of this Warrant
unless the same consideration is also offered to all holders of the
Warrants.

    11.  Governing Law; Jurisdiction.  This Warrant shall be
         ---------------------------
governed by and construed in accordance with the internal laws of the
State of New York, without giving effect to any of the conflicts of
law principles which would result in the application of the
substantive law of another jurisdiction.  This Warrant shall not be
interpreted or construed with any presumption against the party
causing this Warrant to be drafted.  The Issuer and the Holder agree
that venue for any dispute arising under this Warrant will lie
exclusively in the state or federal courts located in New York County,
New York, and the parties irrevocably waive any right to raise forum
non conveniens or any other argument that New York is not the proper
venue.  The Issuer and the Holder irrevocably consent to personal
jurisdiction in the state and federal courts of the state of New York.
The Issuer and the Holder consent to process being served in any such
suit, action or proceeding by mailing a copy thereof to such party at
the address in effect for notices to it under this Warrant and agrees
that such service shall constitute good and sufficient service of
process and notice thereof.  Nothing in this Section 12 shall affect
or limit any right to serve process in any other manner permitted by
law.  The Issuer and the Holder hereby agree that the prevailing party
in any suit, action or proceeding arising out of or relating to this
Warrant or the Purchase Agreement, shall be entitled to reimbursement
for reasonable legal fees from the non-prevailing party.  The parties
hereby waive all rights to a trial by jury.

    12.  Notices.  Any notice, demand, request, waiver or other
         -------
communication required or permitted to be given hereunder shall be in
writing and shall be effective (a) upon hand delivery by telecopy or
facsimile at the address or number designated below (if delivered on a
business day during normal business hours where such notice is to be
received), or the first business day following such delivery (if
delivered other than on a business day during normal business hours
where such notice is to be received) or (b) on the second business day
following the date of mailing by express courier service, fully
prepaid, addressed to such address, or upon actual receipt of such
mailing, whichever shall first occur.  The addresses for such
communications shall be:

If to the Issuer:     Dentalserv.com
                      [Address]
                      Attention:
                      Tel. No.:
                      Fax No.:

with copies (which
copies shall not
constitute notice)

                      [Dentalserv.com, Counsel]
                      Tel. No.:
                      Fax No.:

                               -19-
<PAGE>

If to any Holder:     At the address of such Holder set forth on
                      Exhibit A to this Agreement, with copies to
                      Holder's counsel as set forth on Exhibit A or
                      as specified in writing by such Holder with
                      copies to:

with copies (which
copies shall not
constitute notice)
to:                   Lord Bissell & Brook LLP
                      885 Third Avenue, 26th Floor
                      New York, New York 10022
                      Attention:
                      Tel No.: (212) 812-8314
                      Fax No.: (212) 812-8374

    Any party hereto may from time to time change its address for
notices by giving written notice of such changed address to the other
party hereto.

    13.  Warrant Agent.  The Issuer may, by written notice to each
         -------------
Holder of this Warrant, appoint an agent having an office in New York,
New York for the purpose of issuing shares of Warrant Stock on the
exercise of this Warrant pursuant to subsection (b) of Section 2
hereof, exchanging this Warrant pursuant to subsection (d) of Section
2 hereof or replacing this Warrant pursuant to subsection (d) of
Section 3 hereof, or any of the foregoing, and thereafter any such
issuance, exchange or replacement, as the case may be, shall be made
at such office by such agent.

    14.  Remedies.  The Issuer stipulates that the remedies at law
         --------
of the Holder of this Warrant in the event of any default or
threatened default by the Issuer in the performance of or compliance
with any of the terms of this Warrant are not and will not be adequate
and that, to the fullest extent permitted by law, such terms may be
specifically enforced by a decree for the specific performance of any
agreement contained herein or by an injunction against a violation of
any of the terms hereof or otherwise.

    15.  Successors and Assigns.  This Warrant and the rights
         ----------------------
evidenced hereby shall inure to the benefit of and be binding upon the
successors and assigns of the Issuer, the Holder hereof and (to the
extent provided herein) the Holders of Warrant Stock issued pursuant
hereto, and shall be enforceable by any such Holder or Holder of
Warrant Stock.

    16.  Modification and Severability.  If, in any action before
         -----------------------------
any court or agency legally empowered to enforce any provision
contained herein, any provision hereof is found to be unenforceable,
then such provision shall be deemed modified to the extent necessary
to make it enforceable by such court or agency.  If any such provision
is not enforceable as set forth in the preceding sentence, the
unenforceability of such provision shall not affect the other
provisions of this Warrant, but this Warrant shall be construed as if
such unenforceable provision had never been contained herein.

    17.  Headings.  The headings of the Sections of this Warrant are
         --------
for convenience of reference only and shall not, for any purpose, be
deemed a part of this Warrant.

                               -20-
<PAGE>

    18.  Registration Rights.  The Holder of this Warrant is
         -------------------
entitled to the benefit of certain registration rights with respect to
the shares of Warrant Stock issuable upon the exercise of this Warrant
pursuant to that certain Registration Rights Agreement, of even date
herewith, by and among the Company and Persons listed on Schedule I
thereto (the "Registration Rights Agreement") and the registration
rights with respect to the shares of Warrant Stock issuable upon the
exercise of this Warrant by any subsequent Holder may only be assigned
in accordance with the terms and provisions of the Registrations
Rights Agreement.

         [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                               -21-
<PAGE>

       IN WITNESS WHEREOF, the Issuer has executed this Series C Warrant
as of the day and year first above written.

                                 DENTALSERV.COM

                                 By:___________________________________
                                    Name:
                                    Title:

                               -22-
<PAGE>

                          EXERCISE FORM
                        SERIES C WARRANT

                         DENTALSERV.COM

The undersigned _______________, pursuant to the provisions of the
within Warrant, hereby elects to purchase _____ shares of Common Stock
of Dentalserv.com covered by the within Warrant.

Dated: _________________         Signature      ______________________

                                 Address        ______________________

                                                ______________________

Number of shares of Common Stock beneficially owned or deemed
beneficially owned by the Holder on the date of Exercise:_____________

The undersigned is an "accredited investor" as defined in Regulation D
under the Securities Act of 1933, as amended.

The undersigned intends that payment of the Warrant Price shall be
made as (check one):

          Cash Exercise _______

          Cashless Exercise _______

If the Holder has elected a Cash Exercise, the Holder shall pay the
sum of $________ by certified or official bank check (or via wire
transfer) to the Issuer in accordance with the terms of the Warrant.
If the Holder has elected a Cashless Exercise, a certificate shall be
issued to the Holder for the number of shares equal to the whole
number portion of the product of the calculation set forth below,
which is ___________.   The Company shall pay a cash adjustment in
respect of the fractional portion of the product of the calculation
set forth below in an amount equal to the product of the fractional
portion of such product and the Per Share Market Value on the date of
exercise, which product is ____________.

    X = Y - (A)(Y)
            ------
               B

Where:

The number of Ordinary Shares to be issued to the Holder _________("X").

The number of Ordinary Shares purchasable upon exercise of all of the
Warrant or, if only a portion of the Warrant is being exercised, the

                               -23-
<PAGE>

portion of the Warrant being exercised __________ ("Y").

The Warrant Price ______________ ("A").

The Per Share Market Value of one Ordinary Share _____________ ("B").

                            ASSIGNMENT

FOR VALUE RECEIVED, _________________ hereby sells, assigns and
transfers unto __________________ the within Warrant and all rights
evidenced thereby and does irrevocably constitute and appoint
_____________, attorney, to transfer the said Warrant on the books of
the within named corporation.

Dated: _________________         Signature      ______________________

                                 Address        ______________________

                                                ______________________

                         PARTIAL ASSIGNMENT

FOR VALUE RECEIVED, _________________ hereby sells, assigns and
transfers unto __________________ the right to purchase _________
shares of Warrant Stock evidenced by the within Warrant together with
all rights therein, and does irrevocably constitute and appoint
___________________, attorney, to transfer that part of the said
Warrant on the books of the within named corporation.

Dated: _________________         Signature      ______________________

                                 Address        ______________________

                                                ______________________

                     FOR USE BY THE ISSUER ONLY:

This Warrant No. W-___ canceled (or transferred or exchanged) this
_____ day of ___________, _____, shares of Common Stock issued
therefor in the name of _______________, Warrant No. W-_____ issued
for ____ shares of Common Stock in the name of _______________.

                              -24-
<PAGE>EX-10.1

 

Exhibit 10.1

Execution Copy

PURCHASE AGREEMENT

dated as of August 19, 2007

between

ENZON PHARMACEUTICALS, INC.

and

DRUG ROYALTY LP 2

 

 

TABLE OF CONTENTS

	 	 	 	 	 
	 	 	Page
	ARTICLE I DEFINITIONS
	 	 	1	 
	 
	 	 	 	 
	Section 1.01 Definitions
	 	 	1	 
	 
	 	 	 	 
	ARTICLE II PURCHASE AND SALE OF THE PURCHASED INTEREST
	 	 	8	 
	 
	 	 	 	 
	Section 2.01 Purchase and Sale
	 	 	8	 
	Section 2.02 Transfers and Payments in Respect of the Purchased Interest
	 	 	9	 
	Section 2.03 Purchase Price
	 	 	9	 
	Section 2.04 No Assumed Obligations
	 	 	10	 
	Section 2.05 Excluded Assets
	 	 	10	 
	 
	 	 	 	 
	ARTICLE III REPRESENTATIONS AND WARRANTIES OF ENZON
	 	 	10	 
	 
	 	 	 	 
	Section 3.01 Organization
	 	 	10	 
	Section 3.02 Corporate Authorization
	 	 	11	 
	Section 3.03 Governmental and Third Party Authorization
	 	 	11	 
	Section 3.04 Ownership
	 	 	11	 
	Section 3.05 Solvency
	 	 	11	 
	Section 3.06 Litigation
	 	 	12	 
	Section 3.07 Compliance with Laws
	 	 	12	 
	Section 3.08 Conflicts
	 	 	12	 
	Section 3.09 Broker’s Fees
	 	 	13	 
	Section 3.10 Patent Rights
	 	 	13	 
	Section 3.11 Regulatory Approval, Manufacturing and Marketing
	 	 	14	 
	Section 3.12 Subordination
	 	 	15	 
	Section 3.13 License Agreement
	 	 	15	 
	Section 3.14 Set-off
	 	 	16	 
	 
	 	 	 	 
	ARTICLE IV REPRESENTATIONS AND WARRANTIES OF THE PURCHASER
	 	 	16	 
	 
	 	 	 	 
	Section 4.01 Organization
	 	 	16	 
	Section 4.02 Authorization
	 	 	17	 
	Section 4.03 Broker’s Fees
	 	 	17	 
	Section 4.04 Conflicts
	 	 	17	 
	 
	 	 	 	 
	ARTICLE V COVENANTS
	 	 	17	 
	 
	 	 	 	 
	Section 5.01 Books and Records
	 	 	17	 
	Section 5.02 Confidentiality; Public Announcement
	 	 	18	 
	Section 5.03 Quarterly Reports
	 	 	19	 
	Section 5.04 Commercially Reasonable Efforts; Further Assurance
	 	 	19	 

- i -

 

	 	 	 	 	 
	 	 	Page
	Section 5.05 Remittance to Joint Concentration Account
	 	 	20	 
	Section 5.06 License Agreement
	 	 	21	 
	Section 5.07 Audits
	 	 	24	 
	Section 5.08 Notice
	 	 	25	 
	 
	 	 	 	 
	ARTICLE VI THE CLOSING; CONDITIONS TO CLOSING
	 	 	26	 
	 
	 	 	 	 
	Section 6.01 Closing
	 	 	26	 
	Section 6.02 Conditions Applicable to the Purchaser in Closing
	 	 	26	 
	Section 6.03 Conditions Applicable to Enzon in Closing
	 	 	28	 
	 
	 	 	 	 
	ARTICLE VII EXPIRATION
	 	 	29	 
	 
	 	 	 	 
	Section 7.01 Expiration Date
	 	 	29	 
	Section 7.02 Effect of Expiration
	 	 	29	 
	 
	 	 	 	 
	ARTICLE VIII MISCELLANEOUS
	 	 	29	 
	 
	 	 	 	 
	Section 8.01 Survival
	 	 	29	 
	Section 8.02 Specific Performance
	 	 	30	 
	Section 8.03 Notices
	 	 	30	 
	Section 8.04 Successors and Assigns
	 	 	31	 
	Section 8.05 Indemnification
	 	 	32	 
	Section 8.06 Independent Nature of Relationship
	 	 	34	 
	Section 8.07 Tax
	 	 	34	 
	Section 8.08 Entire Agreement
	 	 	35	 
	Section 8.09 Governing Law
	 	 	36	 
	Section 8.10 Waiver of Jury Trial
	 	 	36	 
	Section 8.11 Severability
	 	 	37	 
	Section 8.12 Counterparts; Effectiveness
	 	 	37	 
	Section 8.13 Amendments; No Waivers
	 	 	37	 
	Section 8.14 Interpretation
	 	 	37	 

- ii -

 

PURCHASE AGREEMENT

     PURCHASE AGREEMENT (this “Agreement”) is made and entered into as of August 19, 2007
by and among Enzon Pharmaceuticals, Inc., a Delaware corporation (“Enzon”), and Drug
Royalty LP 2, a limited partnership organized under the laws of the State of Delaware (the
“Purchaser”).

     WHEREAS, Enzon has the right to receive Royalties based on the worldwide Net Sales of the
Product under the License Agreement; and

     WHEREAS, Enzon wishes to sell, assign, convey and transfer to the Purchaser, and the Purchaser
wishes to purchase from Enzon, the Purchased Interest, upon and subject to the terms and conditions
hereinafter set forth; and

     NOW, THEREFORE, in consideration of the mutual covenants, agreements representations and
warranties set forth herein, the parties hereto agree as follows:

ARTICLE I

DEFINITIONS

     Section 1.01 Definitions.

     The following terms, as used herein, shall have the following meanings:

     “Affiliate” shall mean any Person that controls, is controlled by, or is under common
control with another Person. For purposes of this definition, “control” shall mean (i) in
the case of corporate entities, direct or indirect ownership of at least fifty percent (50%) of the
stock or shares having the right to vote for the election of directors, and (ii) in the case of
non-corporate entities, direct or indirect ownership of at least fifty percent (50%) of the equity
interests with the power, or the power by contract or otherwise, to direct the management and
policies of such non-corporate entities.

     “Agreement” shall have the meaning set forth in the first paragraph hereof.

     “Audit Costs” shall mean, with respect to any audit described hereunder with respect
to amounts payable or paid under this Agreement or any License Party Audit, the cost of such audit,
including all fees, costs and expenses incurred in connection therewith.

     “Bankruptcy Event” shall mean the occurrence of any of the following:

(i) Enzon shall commence any case, proceeding or other action (a) under any existing
or future law of any jurisdiction, domestic or foreign, relating to bankruptcy,
insolvency, reorganization, relief of debtors or the like, seeking to have an order
for relief entered with respect to it, or seeking to adjudicate it bankrupt or
insolvent, or seeking reorganization, arrangement,

 

 

adjustment, winding-up, liquidation, dissolution, composition or other relief with
respect to it or its respective debts, or (b) seeking appointment of a receiver,
trustee, custodian or other similar official for it or for all or any portion of its
assets, or Enzon shall make a general assignment for the benefit of its respective
creditors; or

(ii) there shall be commenced against Enzon any case, proceeding or other action of
a nature referred to in clause (i) above which remains undismissed, undischarged or
unbonded for a period of ninety (90) calendar days; or

(iii) there shall be commenced against Enzon any case, proceeding or other action
seeking issuance of a warrant of attachment, execution, distraint or similar process
against (a) all or any substantial portion of its assets and/or (b) the Royalties,
which results in the entry of an order for any such relief which shall not have been
vacated, discharged, stayed, satisfied or bonded pending appeal within forty-five
(45) calendar days from the entry thereof; or

(iv) Enzon shall take any action in furtherance of, or indicating its consent to,
approval of, or acquiescence in, any of the acts set forth in clause (i), (ii) or
(iii) above.

     “Bill of Sale” shall mean the Bill of Sale pursuant to which Enzon shall assign to the
Purchaser all of its rights and interests in and to the Purchased Interest purchased hereunder,
which Bill of Sale shall be in the form of Exhibit A.

     “BLA” shall mean a biologic license application or its predecessor application, a
product license application, and all amendments and supplements thereto for regulatory approval by
the FDA, as defined under the Public Health Service Act as such act or regulations thereunder may
be amended, supplemented or replaced from time to time, filed with the FDA in the United States or
an equivalent application filed with a Regulatory Agency in any country outside of the United
States.

     “Business Day” shall mean any day other than a Saturday, a Sunday, any day which is a
legal holiday under the laws of the State of New York or New Jersey, or the Province of Ontario, or
any day on which banking institutions located in the State of New York or New Jersey, or in the
Province of Ontario or in the state in which the Depositary Bank is located are authorized or
required by law or other governmental action to close.

     “Closing” shall have the meaning set forth in Section 6.01.

     “Closing Date” shall have the meaning set forth in Section 6.01(a).

 - 2 - 

 

     “Confidential Information” shall mean the Patent Rights, know-how (including the
Know-How), trade secrets, confidential business information, financial data and other like
information (including ideas, research and development, formulas, schematics, compositions,
technical data, specifications, customer and supplier lists, pricing and cost information, and
business and marketing plans and proposals), inventory, ideas, algorithms, processes, computer
software programs or applications (in both source code and object code form), client lists and
tangible or intangible proprietary information or material. Notwithstanding the foregoing
definition, Confidential Information shall not include information that is (i) already in the
public domain at the time the information is disclosed, (ii) thereafter becomes lawfully obtainable
from other sources, (iii) is required to be disclosed in any document to be filed with any
Governmental Authority or (iv) is required to be disclosed by court or administrative order or
under securities laws, rules and regulations applicable to Enzon or the Purchaser or their
respective Affiliates, as the case may be, or pursuant to the rules and regulations of any stock
exchange or stock market on which securities of Enzon or the Purchaser or their respective
Affiliates may be listed for trading.

     “Deposit Accounts” shall mean, collectively, the Joint Concentration Account, Enzon
Concentration Account and the Purchaser Concentration Account, each established and maintained
pursuant to the Deposit Agreement and this Agreement.

     “Deposit Agreement” shall mean any agreement (including initially that certain Deposit
and Account Control Agreement) entered into by the Depositary Bank, Enzon and the Purchaser, in the
form of Exhibit B attached hereto, pursuant to which, among other things, the Joint
Concentration Account, the Purchaser Concentration Account and the Enzon Concentration Account
shall be established and maintained.

     “Depositary Bank” shall mean The Bank of New York or such other bank or financial
institution approved by each of the Purchaser and Enzon.

     “Discrepancy” shall have the meaning set forth in Section 2.02(b).

     “Discrepancy Notice” shall have the meaning set forth in Section 5.07(b).

     “Disposition” shall have the meaning set forth in Section 5.06(g).

     “Dispute”or “Disputes” shall have the meaning set forth in Section 3.10(e).

     “EMEA” shall mean the European Medicines Agency.

     “Enzon” shall mean Enzon Pharmaceuticals, Inc., a Delaware corporation, and its
successors and assigns.

 - 3 - 

 

     “Enzon Concentration Account” shall mean a segregated account established and
maintained at the Depositary Bank pursuant to the terms of the Deposit Agreement and this
Agreement. The Enzon Concentration Account shall be the account into which the funds remaining in
the Joint Concentration Account after payment therefrom of the amounts payable to the Purchaser
pursuant to this Agreement are transferred in accordance with the terms of the Deposit Agreement
and this Agreement.

     “Enzon Development Know-How” shall mean “Enzon Development Know-How” as such term is
defined in the License Agreement.

     “Enzon Existing Know-How” shall mean “Enzon Existing Know-How” as such term is defined
in the License Agreement.

     “Enzon Indemnified Party” shall have the meaning set forth in Section 8.05(b).

     “Enzon Representatives” shall mean Jeffrey H. Buchalter, Craig Tooman, Ivan Horak,
Ralph del Campo and Paul Davit, who constitute all of Enzon’s executive officers, Scott Waldman,
Enzon’s Associate General Counsel and Peggy Albanese, Enzon’s Director, Intellectual Property.

     “E.U.” shall mean the European Union.

     “Excluded Liabilities and Obligations” shall have the meaning set forth in Section
2.04.

     “FDA” shall mean the United States Food and Drug Administration and any successor
agency thereto.

     “Final Payment Date” shall have the meaning set forth in Section 2.03(b).

     “Governmental Authority” shall mean any government, court, regulatory or
administrative agency or commission, or other governmental authority, agency or instrumentality,
whether foreign, federal, state or local (domestic or foreign), including each Patent Office, the
FDA, the EMEA, the MHLW and any other government authority in any country.

     “Independent Accountants” shall have the meaning set forth in Section 5.07(b).

     “Initial Purchase Price” shall have the meaning set forth in Section 2.03(a).

     “Joint Concentration Account” shall mean the deposit account established and
maintained at the Depositary Bank pursuant to the Deposit Agreement and this Agreement. The Joint
Concentration Account shall be the account into which all payments of the Royalties are to be
remitted as provided herein and the account from

 - 4 - 

 

which the Depositary Bank transfers funds into the Purchaser Concentration Account and the
Enzon Concentration Account.

     “Know-How” shall mean the Enzon Existing Know-How and the Enzon Development Know-How.

     “Knowledge” shall mean, with respect to Enzon, the actual knowledge of the Enzon
Representatives.

     “License Agreement” shall mean the Development, License and Supply Agreement between
Schering Corporation and Enzon, Inc. (the former name of Enzon Pharmaceuticals, Inc.) effective
November 14, 1990, and as amended by written amendments executed by Enzon and Schering Corporation
effective as of the following dates: December 10, 1991, October 30, 1992, March 2, 1993, June 30,
1995, June 24, 1999, September 13, 1999, September 22, 2000 and August 10, 2001, each as in effect
on the date of this Agreement.

     “License Party Audit” shall have the meaning set forth in Section 5.08(a).

     “Lien” shall mean any assignment, lien, hypothecation, charge, instrument, license,
preference, priority, security agreement, security interest, interest, mortgage, option, privilege,
pledge, liability, covenant, order, tax, right of recovery, trust or deemed trust (whether
contractual, statutory or otherwise arising) or any encumbrance, right or claim of any other person
of any kind whatsoever whether choate or inchoate, filed or unfiled, noticed or unnoticed, recorded
or unrecorded, contingent or non-contingent, material or non-material, known or unknown.

     “Losses” shall mean collectively, any and all claims, damages, losses, judgments,
liabilities, costs and expenses (including reasonable expenses of investigation and reasonable
attorneys’ fees and expenses).

     “Material Adverse Effect” shall mean a material adverse effect on (i) the validity or
enforceability of any of the Transaction Documents or the License Agreement, (ii) the ability of
Enzon (or its permitted assignee) to perform any of its obligations under any of the Transaction
Documents or to consummate the transactions contemplated thereunder, (iii) the rights or remedies
of the Purchaser under any of the Transaction Documents, (iv) the right of Enzon to receive any
Royalties or the timing, amount or duration of such Royalties, (v) the Purchased Interest, or (vi)
the Patent Rights.

     “MHLW” shall mean the Ministry of Health, Labor and Welfare of Japan.

     “Net Sales” shall mean “Net Sales” as such term is defined in the License Agreement.

 - 5 - 

 

     “Patent Office” shall mean the respective patent office, including the U.S. Patent and
Trademark Office and any comparable foreign patent office, for any Patent Rights.

     “Patent Rights” shall mean “Enzon Patent Rights” as such term is defined in the
License Agreement, including those identified on Schedule 3.10(a).

     “Permitted Set-off” shall mean any Set-off expressly permitted under Sections 5.1.1,
7.1(b), 7.2, 8.3 or 8.4 of the License Agreement.

     “Person” shall mean an individual, corporation, partnership, limited liability
company, association, trust or other entity or organization, but not including a government or
political subdivision or any agency or instrumentality of such government or political subdivision.

     “Product” shall mean “Agreement Product” as such term is defined in the License
Agreement, and shall include but not be limited to, the product PEG-Intron, which is marketed by
Schering.

     “Product Payment Amount” shall mean an amount equal to twenty-five percent (25%) of
the Royalties actually paid.

     “Purchaser” shall have the meaning set forth in the first paragraph hereof.

     “Purchaser Concentration Account” shall mean a segregated account established for the
benefit of the Purchaser and maintained at the Depositary Bank pursuant to the terms of the Deposit
Agreement and this Agreement. The Purchaser Concentration Account shall be the account into which
the funds first held in the Joint Concentration Account that are payable to the Purchaser pursuant
to this Agreement are transferred by the Depositary Bank in accordance with the terms of this
Agreement and the Deposit Agreement.

     “Purchaser Indemnified Party” shall have the meaning set forth in Section 8.05(a).

     “Purchased Interest” shall mean an undivided 100% interest in twenty-five percent
(25%) of the Royalties.

     “Purchase Price” shall be the amount set forth in Section 2.03(b) which shall be
payable in United States Dollars.

     “Quarterly Report” shall mean, with respect to the relevant calendar quarter of Enzon,
(i) a report showing all amounts paid to the Purchaser under this Agreement during such quarter and
showing in detail the basis for the calculation of such payments, and (ii) all information and data
deliverable to Enzon by Schering pursuant to the License

 - 6 - 

 

Agreement, in each case subject to the confidentiality obligations Enzon has with Schering
under the License Agreement.

     “Regulatory Agency” shall mean a Governmental Authority with responsibility for the
approval of the marketing and sale of pharmaceuticals in any country or other regulation of
pharmaceuticals.

     “Regulatory Approvals” shall mean, collectively, all approved BLAs and approved
supplements thereto and other regulatory approvals, registrations, certificates, authorizations,
permits and supplements thereto, as well as associated materials (including the product dossier)
pursuant to which the Product may be marketed, sold and distributed in a jurisdiction, issued by
the appropriate Regulatory Agency.

     “Royalty” or “Royalties” shall mean the gross amount of (i) all royalties (and
other amounts in lieu thereof) paid or payable to Enzon under the License Agreement (or any
amendment or successor or replacement agreement thereto) with respect to worldwide Net Sales of the
Product which occur on or after the Royalties Commencement Date, and (ii) any recovery, damages or
settlement amounts received by Enzon in substitution for, as replacement for or otherwise in lieu
of royalties payable to Enzon pursuant to the License Agreement on account of infringement of the
Patent Rights or Know-How by any third parties in the field of pegylated interferon alpha.

     “Royalties Commencement Date” shall mean July 1, 2007.

     “Schering” shall mean Schering Corporation and its Affiliates.

     “Set-off” shall have the meaning set forth in Section 3.14.

     “Sublicensee” shall mean any sublicensee of Schering under the License Agreement.

     “Subsequent Consideration” shall have the meaning set forth in Section 2.03(b).

     “Subsidiary” or “Subsidiaries” shall mean with respect to any Person (i) any
corporation of which the outstanding capital stock having at least a majority of votes entitled to
be cast in the election of directors (or, if there are no such voting interests, 50% or more of the
equity interests) under ordinary circumstances shall at the time be owned, directly or indirectly,
by such Person or by another subsidiary of such Person or (ii) any other Person of which at least a
majority voting interest (or, if there are no such voting interests, 50% or more of the equity
interests) under ordinary circumstances is at the time owned, directly or indirectly, by such
Person or by another subsidiary of such Person.

     “Threshold Amount” shall have the meaning set forth in Section 2.03(b).

 - 7 - 

 

     “Transaction Documents” shall mean, collectively, this Agreement, the Bill of Sale and
the Deposit Agreement.

     “UCC” shall mean the Uniform Commercial Code (or any similar or equivalent
legislation) as in effect in any applicable jurisdiction.

     “Valid Claim” shall have the meaning set forth in the License Agreement.

ARTICLE II

PURCHASE AND SALE OF THE PURCHASED INTEREST

     Section 2.01 Purchase and Sale.

     (a) Subject to the terms and conditions of this Agreement, Enzon hereby sells, assigns,
transfers and conveys to the Purchaser all right, title and interest in and to the Purchased
Interest free and clear of any and all Liens.

     (b) Enzon and the Purchaser intend and agree that the sale, assignment and transfer of the
Purchased Interest under this Agreement shall be, and is, a true sale by Enzon to the Purchaser
that is absolute and irrevocable and that provides the Purchaser with the full benefits of
ownership of the Purchased Interest, and neither Enzon nor the Purchaser intends the transactions
contemplated hereunder to be, or for any purpose characterized as, a loan from the Purchaser to
Enzon. Enzon waives any right to contest or otherwise assert that this Agreement is other than a
true sale by Enzon to the Purchaser under applicable law, which waiver shall be enforceable against
Enzon in any bankruptcy or insolvency proceeding relating to Enzon.

     (c) Enzon hereby consents to the Purchaser recording and filing, at the Purchaser’s sole cost
and expense, financing statements in the appropriate filing offices under the UCC (and continuation
statements with respect to such financing statements when applicable) meeting the requirements of
applicable law in such manner and in such jurisdictions as are necessary or appropriate to perfect
the purchase by the Purchaser of the Purchased Interest. If, notwithstanding the intent of Enzon
and the Purchaser in this regard, the sale, transfer, assignment and conveyance of the Purchased
Interest contemplated by this Agreement is held not to be a sale, this Agreement shall constitute a
security agreement and Enzon does hereby grant to the Purchaser a first priority security interest
in and to all of Enzon’s right, title and interest in, to and under the Purchased Interest.

     (d) The conveyance to the Purchaser of the Purchased Interest shall be reflected on Enzon’s
balance sheet and other financial statements as a sale of the Purchased Interest by Enzon to the
Purchaser and shall be reflected on the Purchaser’s balance sheet and other financial statements as
a purchase of the Purchased Interest by the Purchaser from Enzon.

 - 8 - 

 

     Section 2.02 Transfers and Payments in Respect of the Purchased Interest.

     The Purchaser shall be entitled to receive the following transfers and payments in respect of
the Purchased Interest:

     (a) Cash in respect of the Royalties shall be paid into the Joint Concentration Account, from
which the Product Payment Amount shall be transferred from the Joint Concentration Account into the
Purchaser Concentration Account on the day of receipt pursuant and subject to Section 5.05. In the
event Enzon receives any Royalties, Enzon shall hold such amounts in trust for the benefit of the
Purchaser, provide the Purchaser with an accounting thereof, and, within two (2) Business Days
after receipt thereof, deposit such amounts into the Joint Concentration Account by wire transfer
of immediately available funds.

     (b) For avoidance of doubt, the parties understand and agree that if Schering fails to pay any
Royalties when Enzon or the Purchaser reasonably believes they are due under the License Agreement
(each such unpaid amount, a “Discrepancy”), other than as a result of a disagreement
relating to any breach of the License Agreement by Enzon, and the Discrepancy relates to (i) when
or whether any Royalties are owed to Enzon, or (ii) the amount of any Permitted Set-off taken by
Schering, then Enzon shall not be obligated to pay to the Purchaser or otherwise compensate or make
the Purchaser whole with respect to any such Discrepancy, but instead Enzon shall use commercially
reasonable efforts to recover such Discrepancy from Schering as contemplated by Sections 5.06(c)
and (d); provided that the foregoing shall not limit any rights any Purchaser Indemnified Party may
have as a result of a breach of any representation, warranty, covenant or other provision of this
Agreement.

     Section 2.03 Purchase Price.

     In full consideration for the sale, assignment, transfer and conveyance of the Purchased
Interest, and subject to the terms and conditions set forth herein, the Purchaser shall pay to
Enzon, or its designee:

     (a) on the Closing Date, the sum of NINETY-TWO MILLION FIVE HUNDRED THOUSAND DOLLARS
($92,500,000) (the “Initial Purchase Price”); and

     (b) no more than five (5) Business Days following the end of the first quarterly period of
2012 (the “Final Payment Date”), the sum of FIFTEEN MILLION DOLLARS ($15,000,000) (the
“Subsequent Consideration”), provided that the cumulative Product Payment Amount received
by the Purchaser prior to the Final Payment Date with respect to Net Sales of the Product which
occur between the Royalties Commencement Date and December 31, 2011 is at least EIGHTY MILLION
DOLLARS ($80,000,000) (such cumulative Product Payment Amount with regard to such Net Sales, the
“Threshold Amount”), provided that if the Threshold Amount is not received by the Purchaser
prior

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to the Final Payment Date but the Threshold Amount is payable by Schering under the License
Agreement prior to the Final Payment Date, then the Purchaser will pay the Subsequent Consideration
within two (2) Business Days after receipt of the Threshold Amount after the Final Payment Date, in
each case, by wire transfer to an account designated in writing by Enzon at least two (2) Business
Days prior to the relevant payment date (the amounts described in Sections 2.03(a) and (b),
collectively, the “Purchase Price”).

     Section 2.04 No Assumed Obligations.

     Notwithstanding any provision in this Agreement or any other writing to the contrary, the
Purchaser is acquiring only the Purchased Interest and is not assuming any liability or obligation
of Enzon or any of its Affiliates of whatever nature, whether presently in existence or arising or
asserted hereafter, whether under the License Agreement or any Transaction Document or otherwise.
All such liabilities and obligations shall be retained by and remain obligations and liabilities of
Enzon or its Affiliates (the “Excluded Liabilities and Obligations”).

     Section 2.05 Excluded Assets.

     The Purchaser does not, by purchase of the rights granted hereunder or otherwise pursuant to
any of the Transaction Documents, acquire any assets or contract rights of Enzon under the License
Agreement or any other assets of Enzon, other than the Purchased Interest.

ARTICLE III

REPRESENTATIONS AND WARRANTIES OF ENZON

     Enzon hereby represents and warrants to the Purchaser as of the date first written above and
the Closing Date, the following:

     Section 3.01 Organization.

     Enzon is a corporation duly incorporated, validly existing and in good standing under the laws
of the State of Delaware, and has all corporate powers and all licenses, authorizations, consents
and approvals required to carry on its business as now conducted and as proposed to be conducted in
connection with the transactions contemplated by the Transaction Documents. Enzon is duly
qualified to do business as a foreign corporation and is in good standing in every jurisdiction in
which the failure to do so could reasonably be expected to result in a Material Adverse Effect.

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     Section 3.02 Corporate Authorization.

     Enzon has all necessary corporate power and authority to enter into, execute and deliver the
Transaction Documents and to perform all of the obligations to be performed by it hereunder and
thereunder and to consummate the transactions contemplated hereunder and thereunder. The
Transaction Documents have been duly authorized, executed and delivered by Enzon and each
Transaction Document constitutes the legal, valid and binding obligation of Enzon, enforceable
against Enzon in accordance with its respective terms, subject, as to enforcement of remedies, to
bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors’ rights
generally or general equitable principles. As part of their duties at Enzon, the Enzon
Representatives would typically have knowledge of the matters covered by the representations and
warranties made by Enzon in this Agreement, provided that the Enzon Representatives have not
conducted any inquiry with regard to any of such representations and warranties which are subject
to Enzon’s Knowledge.

     Section 3.03 Governmental and Third Party Authorization.

     The execution and delivery by Enzon of the Transaction Documents, and the performance by Enzon
of its obligations and the consummation of any of the transactions contemplated hereunder and
thereunder, does not require any consent, approval, license, order, authorization, or declaration
from, notice to, action or registration by, or filing with any Governmental Authority or any other
Person.

     Section 3.04 Ownership.

     Enzon is the exclusive owner of the entire right, title (legal and equitable) and interest in
and to the Purchased Interest, the Royalties and the Patent Rights, including the right to sue and
recover for past and future infringement of the Patent Rights, subject to the License Agreement,
free and clear of all Liens. Enzon has duly and legally recorded its ownership interest in the
Enzon Patents in the appropriate agencies in each jurisdiction in which such recordation is
required in order to fully protect Enzon’s ownership rights therein, and Enzon is the exclusive
“owner of record” of the Patent Rights in each such jurisdiction. Upon the sale, assignment,
transfer and conveyance by Enzon of the Purchased Interest to the Purchaser, the Purchaser will
acquire good and marketable title to the Purchased Interest free and clear of all Liens.

     Section 3.05 Solvency.

     Upon consummation of the transactions contemplated by the Transaction Documents (i) the
present fair saleable value of Enzon’s assets will be greater than the amount required to pay its
debts as they become due, (ii) Enzon will not have unreasonably small capital with which to engage
in its business, and (iii) Enzon will not

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incur, nor does it have present plans or intentions to incur, debts or liabilities beyond its
ability to pay such debts or liabilities as they become absolute and matured.

     Section 3.06 Litigation.

     There is no (i) action, suit, arbitration proceeding, claim, investigation or other proceeding
pending or, to the Knowledge of Enzon, threatened against Enzon or any of its Subsidiaries or, to
the Knowledge of Enzon, pending or threatened against Schering or any of its Sublicensees, at law
or in equity or (ii) inquiry by a Governmental Authority pending or, to the Knowledge of Enzon,
threatened against Enzon or any of its Subsidiaries or, to the Knowledge of Enzon, pending or
threatened against Schering or any of its Sublicensees, which in each case with respect to clauses
(i) and (ii) above, if adversely determined, could reasonably be expected to result in a Material
Adverse Effect.

     Section 3.07 Compliance with Laws.

     None of Enzon or any of its Subsidiaries is in violation of, or has violated, or to the
Knowledge of Enzon is under investigation with respect to, or has been threatened to be charged
with or been given notice of any violation of, any law, rule, ordinance or regulation of, or any
judgment, order, writ, decree, permit or license granted, issued or entered by, any Governmental
Authority which could reasonably be expected to result in a Material Adverse Effect.

     Section 3.08 Conflicts.

     (a) Neither the execution and delivery of any of the Transaction Documents nor the performance
or consummation of the transactions contemplated hereby and thereby will: (i) contravene, conflict
with, result in a breach or violation of, constitute a default (with or without notice or lapse of
time, or both) under, or accelerate the performance provided by, in any respects any provisions of,
that in each case or in the aggregate could reasonably be expected to result in a Material Adverse
Effect, (A) any statute, law, rule, ordinance or regulation of any Governmental Authority, or any
judgment, order, writ, decree, permit or license of any Governmental Authority, to which Enzon or
any of its Subsidiaries or any of their respective assets or properties may be subject or bound, or
(B) any contract, agreement, commitment or instrument to which Enzon or any of its Subsidiaries is
a party or by which Enzon or any of its Subsidiaries or any of their respective assets or
properties is bound or committed, including without limitation the License Agreement; (ii)
contravene, conflict with, result in a breach or violation of, constitute a default under, or
accelerate the performance provided by, any provisions of the certificate of incorporation or
by-laws (or other organizational or constitutional documents) of Enzon or any of its Subsidiaries;
(iii) give rise to any right of termination, cancellation or acceleration of any right or
obligation of Enzon or any of

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its Subsidiaries or any other Person; (iv) except as provided in the Transaction Documents,
result in the creation or imposition of any Lien on the Patent Rights, the Product, the License
Agreement, the Royalties or the Purchased Interest; or (v) relieve any party to the License
Agreement of any of its obligations or enable it to terminate, reduce or suspend its obligations
thereunder.

     (b) Enzon has not granted, nor does there exist, any Lien on the License Agreement, the Patent
Rights or the Purchased Interest.

     Section 3.09 Broker’s Fees.

     Enzon has not taken any action that would entitle any Person to any commission or broker’s fee
in connection with the transaction contemplated by the Transaction Documents, except for Goldman
Sachs which will be entitled to a fee payable by Enzon.

     Section 3.10 Patent Rights.

     (a) Schedule 3.10(a) sets forth an accurate and complete list of all Patent Rights.
For each of the patents included in the Patent Rights listed on Schedule 3.10(a), Enzon has
indicated (i) the countries in which such patents are issued, (ii) the patent number, and (iii) the
expected expiration date of the issued patents. Except as disclosed on Schedule 3.10(a),
there are no pending patent applications included in the Patent Rights.

     (b) To the Knowledge of Enzon, each of the issued patents included in the Patent Rights, and
each claim therein, is valid and enforceable.

     (c) Each of patents included in the Patent Rights set forth on Schedule 3.10(a)
generically or specifically claim the “Agreement Product” as defined in the License Agreement
(including PEG-INTRON) or an intermediate in the manufacturing of PEG-INTRON.

     (d) There are no unpaid maintenance or renewal fees payable by Enzon to any third party that
are currently overdue for any of the Patent Rights. No Patent Rights have lapsed or been
abandoned, cancelled or expired. To the Knowledge of Enzon, each individual associated with the
filing and prosecution of the Patent Rights, including the named inventors of the Patent Rights,
has complied in all material respects with all applicable duties of candor and good faith in
dealing with any Patent Office, including any duty to disclose to any Patent Office all information
known to be material to the patentability of each of the Patent Rights, in those jurisdictions
where such duties exist. To the Knowledge of Enzon, all material prior art to each of the patents
comprising the Patent Rights has been disclosed to and considered by the respective patent offices
during prosecution of such Patent Rights.

 - 13 - 

 

     (e) There is no pending, or to the Knowledge of Enzon threatened, action, suit, opposition,
interference, reexamination, injunction, claim, lawsuit, proceeding, hearing, investigation,
complaint, arbitration, mediation, demand, International Trade Commission investigation, decree, or
any other dispute, disagreement, or claim (each, a “Dispute” and collectively, the
“Disputes”), challenging the legality, validity, enforceability, infringement or ownership
of any of the Patent Rights or which would give rise to a credit against or Set-off with respect to
the payments due to Enzon under the License Agreement for the use of the related licensed Patent
Rights, nor to the Knowledge of Enzon is there any infringement of the Patent Rights by any Person.
To the Knowledge of Enzon, there are no Disputes by any third party against Enzon involving the
Product. Enzon has not received any notice of any Dispute involving the Product. Enzon has not
sent any written notice of any Dispute involving the Product. To the Knowledge of Enzon, none of
the Patent Rights are subject to any outstanding injunction, judgment, order, decree, ruling,
charge, settlement or other disposition of a Dispute.

     (f) There is no pending, or to the Knowledge of Enzon, threatened, action, suit, or
proceeding, or any investigation or claim by any Person or Governmental Authority to which Enzon
or, to the Knowledge of Enzon, to which Schering or any of its Sublicensees is or could be a party
that claims that the marketing, sale or distribution of the Product by Schering or any of its
Sublicensees pursuant to the License Agreement does or will infringe on any patent or other
intellectual property rights of any other Person. To the Knowledge of Enzon, there are no pending
U.S., international or foreign patent applications owned by any such other Person, which, if
issued, would limit or prohibit, in any material respect, the manufacture, use or sale of the
Product by Schering or any of its Sublicensees.

     Section 3.11 Regulatory Approval, Manufacturing and Marketing.

     (a) Schering has been and continues to be responsible for the clinical development of the
Product and seeking Regulatory Approval of the Product under the License Agreement and Enzon has no
responsibility for the development of the Product or seeking Regulatory Approval of the Product
under the License Agreement.

     (b) To Enzon’s Knowledge, Schering has complied with its obligations to develop the Product
and seek and obtain Regulatory Approval for the Product set forth in Sections 2.3, 2.4 and 2.10 of
the License Agreement.

     (c) To Enzon’s Knowledge, the Product has received Regulatory Approval for marketing and
distribution in the United States, Canada, Japan, China and the E.U.

     (d) Schering has been, since 1996, and continues to be, responsible for the manufacturing of
the Product under the License Agreement and Enzon has no responsibility for manufacturing the
Product under the License Agreement.

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     (e) Schering has been, and continues to be, and Enzon is not, responsible for the marketing,
promotion, sales and distribution of the Product under the License Agreement. To Enzon’s
Knowledge, as of the date of this Agreement, Schering has complied with its obligations under, and
is not in default under, the License Agreement.

     Section 3.12 Subordination.

     The claims and rights of the Purchaser created by any Transaction Document in and to the
Purchased Interest are not and shall not be subordinated to any creditor of Enzon or any other
Person.

     Section 3.13 License Agreement.

     (a) Other than the License Agreement and the Transaction Documents, there is no contract,
agreement or other arrangement to which either Enzon or any of its Subsidiaries is a party or any
of Enzon’s or its Subsidiaries’ respective assets or properties are bound or committed (i) which
creates a Lien on, affects or otherwise relates to the Purchased Interest, License Agreement,
Royalties or the Patent Rights, or (ii) for which breach, nonperformance, cancellation or failure
to renew could reasonably be expected to result in a Material Adverse Effect.

     (b) Enzon has provided to the Purchaser an accurate, complete and updated copy of the License
Agreement, provided that only those parts of the schedules to the License Agreement that contain
the specifications of, and development plans for, the Product have been redacted from the copy of
the License Agreement provided by Enzon to the Purchaser and such redacted portions of such
schedules do not in any respect modify or supplement the unredacted provisions of the License
Agreement in a manner that adversely affects the Purchaser’s rights and obligations under the
Transaction Documents.

     (c) The License Agreement is the legal, valid and binding obligation of each of Enzon and, to
the Knowledge of Enzon, Schering, enforceable against Enzon and, to the Knowledge of Enzon,
Schering in accordance with its terms, subject, as to enforcement of remedies, to bankruptcy,
insolvency, reorganization, moratorium or similar laws affecting creditors’ rights generally and
general equitable principles. The execution, delivery and performance of the License Agreement was
and is within the corporate powers of Enzon and, to the Knowledge of Enzon, Schering. The License
Agreement was duly authorized by all necessary action on the part of, and validly executed and
delivered by Enzon and, to the Knowledge of Enzon, Schering. There is no breach or default, or
event which upon notice or the passage of time, or both, could give rise to any breach or default,
in the performance of the License Agreement by Enzon or, to the Knowledge of Enzon, Schering.

 - 15 - 

 

     (d) Enzon has not waived any rights or defaults under the License Agreement, that adversely
affects the Purchaser’s rights and obligations under the Transaction Documents.

     (e) Enzon has not received any notice of Schering’s intention to terminate the License
Agreement in whole or in part, or that Enzon is in default of its obligations under the License
Agreement. Enzon has no intention of terminating the License Agreement.

     (f) Except as provided in the License Agreement, Enzon is not a party to any agreement
providing for or permitting a sharing of, reduction in, or set-off against, the Royalties payable
under the License Agreement to Enzon.

     (g) The sale by Enzon of the Purchased Interest to the Purchaser will not require the consent
of Schering under the License Agreement and will not constitute a breach of or event of default
under the License Agreement.

     (h) To the Knowledge of Enzon, the license agreement between Schering and Research Corporation
referred to in Section 7.1(a) of the License Agreement is no longer in effect and no amounts are
due, payable or outstanding by Schering under such license agreement.

     Section 3.14 Set-off.

     Except for Permitted Set-offs, Schering has no right of set-off, rescission, counterclaim,
reduction, deduction or defense (each a “Set-off”) against the Royalties or any other
amounts payable to Enzon under the License Agreement. To date, Schering has not exercised, and to
Enzon’s Knowledge Schering has not had the right to exercise, any such Set-off.

ARTICLE IV

REPRESENTATIONS AND WARRANTIES OF THE PURCHASER

     The Purchaser represents and warrants to Enzon as of the date first written above, and the
Closing Date, the following:

     Section 4.01 Organization.

     The Purchaser is a limited partnership duly formed, validly existing and in good standing
under the laws of the State of Delaware, and the Purchaser has all limited partnership powers and
all licenses, authorizations, consents and approvals required to carry on its business as now
conducted.

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     Section 4.02 Authorization.

     The Purchaser has all necessary power and authority to enter into, execute and deliver the
Transaction Documents and to perform all of the obligations to be performed by it hereunder and
thereunder and to consummate the transactions contemplated hereunder and thereunder. The
Transaction Documents have been duly authorized, executed and delivered by the Purchaser and each
Transaction Document constitutes the legal, valid and binding obligation of the Purchaser,
enforceable against the Purchaser in accordance with its terms, subject, as to enforcement of
remedies, to bankruptcy, insolvency, reorganization, moratorium or similar laws affecting
creditors’ rights generally and general equitable principles.

     Section 4.03 Broker’s Fees.

     The Purchaser has not taken any action that would entitle any Person to any commission or
broker’s fee in connection with the transactions contemplated by the Transaction Documents.

     Section 4.04 Conflicts.

     Neither the execution and delivery of this Agreement or any other Transaction Document nor the
performance or consummation of the transactions contemplated hereby or thereby will: (i)
contravene, conflict with, result in a breach or violation of, constitute a default (with or
without notice or lapse of time, or both) under, or accelerate the performance provided by, in any
material respects any provisions of (A) any statute, law, rule or regulation of any Governmental
Authority, or any judgment, order, writ, decree, permit or license of any Governmental Authority,
to which the Purchaser or any of its assets or properties may be subject or bound; or (B) any
contract, agreement, commitment or instrument to which the Purchaser is a party or by which the
Purchaser or any of its assets or properties is bound or committed; (ii) contravene, conflict with,
result in a breach or violation of, constitute a default under, or accelerate the performance
provided by, any provisions of any organizational or constitutional documents of the Purchaser; or
(iii) require any notification to, filing with, or consent of, any Person or Governmental
Authority.

ARTICLE V

COVENANTS

     The parties covenant and agree as follows:

     Section 5.01 Books and Records.

     (a) Promptly after receipt by Enzon of notice of any action, claim, demand, dispute,
investigation, arbitration or proceeding (commenced or threatened) relating to

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the transactions contemplated by any Transaction Document, the Purchased Interest or the
License Agreement, or any default or termination by any Person under the License Agreement, Enzon
shall inform the Purchaser of the receipt of such notice and the substance of such event and, if in
writing, shall furnish the Purchaser with a copy of such notice and any related materials with
respect to such event, subject to any Enzon confidentiality obligations with Schering pursuant to
the License Agreement.

     (b) Enzon shall keep and maintain, or cause to be kept and maintained, at all times full and
accurate books of account and records adequate to reflect accurately all Royalties paid and/or
payable with respect to the License Agreement and all deposits made into the applicable Deposit
Accounts.

     (c) Promptly after receipt by Enzon of any written notice, certificate, offer, proposal,
correspondence, report or other written communication relating directly to the License Agreement,
the Royalties, the Patent Rights, the Know-How, the Purchased Interest or the Product and material
to the Purchaser’s interest in the Royalties or the Purchased Interest, Enzon shall inform the
Purchaser of such receipt and, subject to Enzon’s confidentiality obligations with Schering
pursuant to the License Agreement, the substance contained therein and, if in writing, subject to
any Enzon confidentiality obligations with Schering pursuant to the License Agreement, shall
furnish the Purchaser with a copy of such notice, certificate, offer, proposal, correspondence,
report or other written communication.

     Section 5.02 Confidentiality; Public Announcement.

     (a) Except as otherwise required by law or the rules and regulations of any securities
exchange or trading system or the FDA or any Governmental Authority with similar regulatory
authority and except as otherwise set forth in this Section 5.02, all information furnished by the
Purchaser to Enzon or by Enzon to the Purchaser, including the Confidential Information, in
connection with this Agreement and any other Transaction Document and the transactions contemplated
hereby and thereby, as well as the terms, conditions and provisions of this Agreement and any other
Transaction Document, shall be kept confidential by the recipient thereof, and shall be used by the
recipient thereof only in connection with this Agreement and any other Transaction Document and the
transactions contemplated hereby and thereby, except to the extent that such information (i) is
already in the public domain at the time the information is disclosed, (ii) thereafter becomes
lawfully obtainable from other sources, (iii) is required to be disclosed in any document to be
filed with any Governmental Authority, or (iv) is required to be disclosed by court or
administrative order or under securities laws, rules and regulations applicable to Enzon or the
Purchaser or their respective Affiliates, as the case may be, or pursuant to the rules and
regulations of any stock exchange or stock market on which securities of Enzon or the Purchaser or
their respective Affiliates may be listed for trading. Notwithstanding the foregoing, Enzon and
the Purchaser may

 - 18 - 

 

disclose such information to their actual and potential partners, directors, employees,
managers, officers, agents, investors, co-investors, insurers and insurance brokers, underwriters,
financing parties (whether equity or debt), equity holders, brokers, lawyers, bankers, consultants,
scientific and technical advisors and other advisors, rating agencies, Affiliates, trustees and
representatives on a need-to-know basis provided that such Persons shall be informed of the
confidential nature of such information and shall be obligated to keep such information
confidential pursuant to obligations of confidentiality no less onerous than those set out herein.
It is understood and agreed that Enzon will be required to disclose the terms of the Transaction
Documents in filings with the Securities and Exchange Commission and to file the Transaction
Documents with the Securities and Exchange Commission.

     (b) Enzon and the Purchaser acknowledge that each party will, after execution of this
Agreement, make a public announcement of the transactions contemplated by the Transaction
Documents. Enzon’s public announcement will be in the form of the press release set out in
Schedule 5.02.

     Section 5.03 Quarterly Reports.

     Enzon shall, within fifteen (15) calendar days following the receipt by Enzon of the reports
required under Section 8.1 of the License Agreement, produce and deliver to the Purchaser a
Quarterly Report for such quarter, together with a certificate of the Chief Financial Officer of
Enzon, certifying that to the knowledge of such officer (i) such Quarterly Report is a true and
complete copy and (ii) any statements and any data and information therein prepared by Enzon are
true, correct and accurate in all material respects.

     Section 5.04 Commercially Reasonable Efforts; Further Assurance.

     (a) Subject to the terms and conditions of this Agreement, each party hereto will use its
commercially reasonable efforts to take, or cause to be taken, all actions and to do, or cause to
be done, all things necessary under applicable laws and regulations to consummate the transactions
contemplated by the Transaction Documents. The Purchaser and Enzon agree to execute and deliver
such other documents, certificates, agreements and other writings and to take such other actions as
may be necessary in order to consummate or implement expeditiously the transactions contemplated by
any Transaction Document and to vest in the Purchaser good, valid and marketable rights and
interests in and to the Purchased Interest free and clear of all Liens. Notwithstanding the
foregoing, Enzon shall not be obligated to seek an amendment to the License Agreement under this
Section 5.04.

     (b) Enzon and the Purchaser shall cooperate and provide assistance as reasonably requested by
the other party at the expense of such other party in connection

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with any litigation, arbitration or other proceeding (whether threatened, existing, initiated,
or contemplated prior to, on or after the date hereof) to which the other party hereto or any of
its officers, directors, shareholders, members, managers, agents or employees is or may become a
party or is or may become otherwise directly or indirectly affected or as to which any such persons
have a direct or indirect interest, in each case relating to any Transaction Document, the
Purchased Interest or the transactions described herein or therein but in all cases excluding any
litigation brought by Enzon against the Purchaser or brought by the Purchaser against Enzon.

     Section 5.05 Remittance to Joint Concentration Account.

     (a) As required by Section 6.02(f), the parties hereto shall enter into a Deposit Agreement,
substantially in the form of Exhibit B attached hereto, which will provide for, among other
things, the establishment and maintenance of the Joint Concentration Account, the Enzon
Concentration Account and the Purchaser Concentration Account in accordance with the terms herein
and therein. The Purchaser Concentration Account shall be held solely for the benefit of the
Purchaser, but shall be subject to the terms and conditions of the Transaction Documents. Funds
deposited into the Joint Concentration Account shall be treated as provided in the Deposit
Agreement. The Purchaser shall have immediate and full access to and control of any funds held in
the Purchaser Concentration Account and such funds shall not be subject to any conditions or
restrictions whatsoever other than those of the Depositary Bank. After the amounts payable to the
Purchaser under Section 2.02 are transferred to the Purchaser Concentration Account, as provided in
the Deposit Agreement, the amounts remaining in the Joint Concentration Account shall then be
transferred to the Enzon Concentration Account. Enzon shall have immediate and full access to and
control of any funds held in the Enzon Concentration Account and such funds shall not be subject to
any conditions or restrictions whatsoever other than those of the Depositary Bank.

     (b) The Purchaser and Enzon shall equally share all fees, expenses and charges of the
Depositary Bank by debiting half of each such fee, expense or charge from the Enzon Concentration
Account and half of each such fee, expense or charge from the Purchaser Concentration Account.

     (c) At all times as Royalties are payable to Enzon, Enzon shall instruct and use commercially
reasonable efforts to cause Schering or any other party from whom Enzon is entitled to receive
Royalties to pay directly into the Joint Concentration Account all Royalties payable by Schering or
such other party (without any withholding or deduction therefrom, except for any Permitted Set-off
and except as provided in Section 8.07(b)) and within one (1) Business Day after the Closing Date,
Enzon shall send to Schering the letter attached hereto as Exhibit E. Enzon shall not,
without the prior written consent of the Purchaser, make any change to the instructions to Schering
under the letter attached hereto as Exhibit E. Without in any way limiting the foregoing,
commencing on the

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Closing Date and at any time thereafter, any and all Royalties received by Enzon shall be held
in trust for the benefit of the Purchaser and directed into the Joint Concentration Account
(without deduction, set-off, claim, counterclaim or offset) within two (2) Business Days of Enzon’s
receipt thereof.

     (d) Neither party hereto shall have any right to terminate the Depositary Bank without the
other party’s prior written consent. Any such consent, which the other party may grant or withhold
in its discretion, shall be subject to the satisfaction of each of the following conditions to the
satisfaction of the other party:

     (1) the successor Depositary Bank shall be reasonably acceptable to the other party;

     (2) the Purchaser and Enzon and the successor Depositary Bank shall have entered into
an agreement substantially in the form of the Deposit Agreement attached hereto as
Exhibit B;

     (3) all funds and items in the accounts subject to the Deposit Agreement to be
terminated shall be transferred to the new accounts held at the successor Depositary Bank
prior to the termination of the then existing Depositary Bank; and

     (4) the Purchaser shall have received written evidence that Schering has been
instructed to remit all future Royalties to the new accounts held at the successor
Depositary Bank.

     Section 5.06 License Agreement.

     (a) Enzon shall comply with its obligations under the provisions of the License Agreement
affecting the Patent Rights, the Royalties and the Purchased Interest, and shall not (i) forgive,
release or compromise any amount owed to or becoming owing to Enzon under the License Agreement
related to the Royalties or the Purchased Interest, (ii) waive, amend, cancel or terminate,
exercise or fail to exercise as provided in Sections 5.06(c) and (d), any of its rights
constituting or involving the right to receive the Royalties, (iii) create or permit to exist any
Lien on the Purchased Interest, Royalties, Know-How or Patent Rights, (iv) challenge or assist in a
challenge of the validity of the Patent Rights, or (v) amend, modify, restate, cancel, supplement,
terminate or waive the License Agreement or any provision of the License Agreement, or grant any
consent thereunder, or agree to do any of the foregoing, including entering into any agreement with
Schering under the provisions of such License Agreement, unless any such action described in this
Section 5.06(a) would reasonably be expected not to have a Material Adverse Effect. Enzon and the
Purchaser agree that for purposes of this Section 5.06(a) the determination of what actions would
reasonably be expected to have a Material Adverse Effect shall be made in the context of what
actions, if taken, would have a

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material adverse effect for an owner of the Purchased Interest, without regard to any other
business of, or assets owned by, such owner of the Purchased Interest.

     (b) Enzon shall promptly provide to the Purchaser copies of any reports or other information
prepared by Schering it receives after the Closing Date pursuant to the License Agreement or
hereunder which are material to the Purchaser’s interest in the Royalties or the Purchased
Interest, that has not been previously provided to the Purchaser by either Enzon or any other
Person (subject to any Enzon confidentiality obligations with Schering pursuant to the License
Agreement).

     (c) Promptly after (i) receiving written or oral notice from Schering, (A) terminating the
License Agreement, (B) alleging any breach of or default under the License Agreement by Enzon
material to the Purchaser’s interest in the Royalties or the Purchased Interest or (C) asserting
the existence of any facts, circumstances or events which alone or together with other facts,
circumstances or events could reasonably be expected (with or without the giving of notice or
passage of time or both) to give rise to a breach of or default under the License Agreement
material to the Purchaser’s interest in the Royalties or the Purchased Interest, or right to
terminate the License Agreement or (ii) Enzon otherwise has Knowledge of any fact, circumstance or
event which alone or together with other facts, circumstances or events could reasonably be
expected (with or without the giving of notice or passage of time or both) to give rise to a breach
of or default under the License Agreement by Enzon material to the Purchaser’s interest in the
Royalties or the Purchased Interest, or a right to terminate the License Agreement by Schering, in
each case, Enzon shall (x) give a written notice to the Purchaser describing in reasonable detail
the relevant breach, default or termination event, including a copy of any written notice received
from Schering, subject to any Enzon confidentiality obligations with Schering pursuant to the
License Agreement and, in the case of any breach or default or alleged breach or default by Enzon,
describing any corrective action Enzon proposes to take and (y) take all commercially reasonable
efforts to cure promptly such breach, default or termination event.

     (d) Promptly after becoming aware of a breach of or default under the License Agreement by
Schering material to the Purchaser’s interest in the Royalties or the Purchased Interest or of the
existence of any facts, circumstances or events which alone or together with other facts,
circumstances or events could reasonably be expected (with or without the giving of notice or
passage of time or both) to give rise to a breach of or default under the License Agreement by
Schering material to the Purchaser’s interest in the Royalties or the Purchased Interest, or a
right to terminate the License Agreement by Enzon, then in each case, Enzon shall (i) give a
written notice to the Purchaser describing in reasonable detail the relevant breach, default or
termination event, including a copy of any written notice that Enzon proposes to send to Schering
and, in the case of any breach or default or alleged breach or default by Schering, describing any
action Enzon proposes to take, and (ii) make all commercially reasonable efforts to enforce all of
its rights and

 - 22 - 

 

remedies thereunder to the extent any failure to enforce such rights or remedies could
reasonably be expected to result in a Material Adverse Effect; provided, however Enzon will not
take any actions under the License Agreement that could reasonably be expected to result in such a
Material Adverse Effect without the prior written consent of the Purchaser, which consent shall not
be unreasonably withheld. Enzon and the Purchaser agree that for purposes of this Section 5.06(d)
the determination of what actions would reasonably be expected to have a Material Adverse Effect
shall be made in the context of what actions, if taken, would have a material adverse effect for an
owner of the Purchased Interest, without regard to any other business of, or assets owned by, such
owner of the Purchased Interest. Enzon will consult with the Purchaser prior to incurring any
costs and expenses in attempting to enforce its rights and remedies under the License Agreement
pursuant to this sub-Section (d), and the Purchaser shall reimburse Enzon for twenty-five percent
(25%) of such reasonable costs and expenses incurred by Enzon.

     (e) Enzon shall, at its sole expense, take any and all actions, and prepare, execute, deliver
and file any and all agreements, documents or instruments, which are reasonably necessary or
desirable to, and to the extent permitted under the License Agreement, (i) diligently maintain the
applicable Patent Rights and (ii) diligently defend (and enforce) such Patent Rights against
infringement or interference by any other Persons, and against any claims of invalidity,
infringement or unenforceability, in any jurisdiction (including by bringing any legal action for
infringement or defending any counterclaim of invalidity or action of a third party for declaratory
judgment of non-infringement or non-interference) to the extent such infringement, interference or
claims could reasonably be expected to result in a Material Adverse Effect. Enzon shall not
unreasonably disclaim or abandon, or fail to take any action reasonably necessary or desirable to
prevent the disclaimer or abandonment of, the applicable Patent Rights to the extent any such
disclaimer, abandonment or failure to act could reasonably be expected to result in a Material
Adverse Effect.

     (f) Enzon shall use commercially reasonable efforts to cause Schering to provide Enzon with
the quarterly statement of Net Sales and royalty calculation required by Section 8.1 of the License
Agreement.

     (g) Enzon may not sell, assign, transfer, deliver or otherwise dispose of all or any of the
Patent Rights, the Know-How, the Royalties (excluding the Purchased Interest), or Enzon’s rights
under the License Agreement to any Person (a “Disposition”) unless (i) subsequent to such
Disposition, Enzon remains responsible for compliance with the Transaction Documents and is in no
way released or discharged from any of its obligations under the Transaction Documents; and (ii)
such Disposition would not cause an adverse effect on Purchaser’s rights and obligations under the
Transaction Documents. In the event Enzon sells additional interests in the Royalties to one or
more third parties, the Purchaser will agree to amend the Deposit Agreement so as to allow (i) the
Joint Concentration Account to be in the name of such third party or third parties in addition to

- 23 -

 

Enzon and the Purchaser and (ii) allow the portion of the Royalties sold to such third party
or parties to be paid to such third party or parties; provided that such third party’s or parties’
portion of the Royalties shall not be paid prior to any payments being made from the Joint
Concentration Account to the Purchaser.

     Section 5.07 Audits.

     (a) To the extent Enzon has the right to perform or cause to be performed inspections or
audits under the License Agreement regarding payments payable and/or paid to Enzon thereunder
(each, a “License Party Audit”), Enzon shall, at the reasonable request of the Purchaser,
cause a License Party Audit to be performed promptly in accordance with the terms of the License
Agreement. In conducting a License Party Audit, subject to the terms of the License Agreement,
Enzon may engage its then retained independent public accounting firm, or, if Enzon elects
otherwise, such other internationally recognized independent public accounting firm reasonably
acceptable to the Purchaser. Promptly after completion of any License Party Audit (whether or not
requested by the Purchaser), Enzon shall promptly deliver to the Purchaser an audit report
summarizing the results of such License Party Audit (subject to any Enzon confidentiality
obligations with Schering pursuant to the License Agreement). If the License Party Audit results
in a determination that Royalties have been understated, then any resulting underpayment will be
paid into the Joint Concentration Account in accordance with Section 5.05(c) and subsequently
seventy-five percent (75%) to Enzon and twenty-five percent (25%) to the Purchaser.

     (b) To the extent that either the Purchaser or Enzon has determined that there is a
discrepancy as to the amounts paid to the Purchaser pursuant to Section 2.02 in any calendar year,
then the party hereto who has made such determination may notify the other party hereto in writing
of such discrepancy indicating in reasonable detail its reasons for such determination (the
“Discrepancy Notice”). In the event that either the Purchaser or Enzon delivers to the
other party a Discrepancy Notice, the Purchaser and Enzon shall meet within ten (10) Business Days
(or such other time as mutually agreed by the parties) after the receiving party has received a
Discrepancy Notice to resolve in good faith such discrepancy. If the discrepancy has been resolved
and, as a result thereof, it is determined that a payment is owing by the Purchaser to Enzon or by
Enzon to the Purchaser, then the party owing such payment shall promptly make such payment to the
other party. If, within thirty (30) Business Days after receipt of the Discrepancy Notice, Enzon
and the Purchaser cannot resolve any such discrepancies, then the Purchaser and Enzon shall
promptly instruct their respective firms of independent certified public accountants to select,
within five (5) Business Days thereafter, a third nationally recognized accounting firm (the
“Independent Accountants”). After offering Enzon and its representatives and the Purchaser
and its representatives the opportunity to present their positions as to the disputed amounts,
which opportunity shall not extend for more than ten (10) Business Days after the Independent
Accountants have been selected, the

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Independent Accountants shall review the disputed matters and the materials submitted by Enzon
and the Purchaser and, as promptly as practicable, deliver to Enzon and the Purchaser a statement
in writing setting forth its determination of the proper treatment of the discrepancies as to which
there was disagreement, and that determination will be final and binding upon the parties hereto
without any further right of appeal.

     (c) The Purchaser and any of its representatives shall have the right, from time to time, to
visit Enzon’s offices and properties where Enzon keeps and maintains its books and records relating
or pertaining to the Purchased Interest for purposes of conducting an audit of such books and
records solely to the extent they relate or pertain to the Purchased Interest, and to inspect, copy
and audit such books and records, during normal business hours, and, upon five (5) Business Days
written notice given by the Purchaser to Enzon, Enzon will provide the Purchaser and any of the
Purchaser’s representatives reasonable access to such books and records and shall permit the
Purchaser and any of the Purchaser’s representatives to discuss the business, operations,
properties and financial and other condition of Enzon solely as they may relate or pertain to the
Purchased Interest with officers of Enzon, and with its independent certified public accountants,
subject to any Enzon confidentiality obligations with Schering pursuant to the License Agreement.
The Purchaser’s visits to Enzon’s offices pursuant to this Section 5.07(c) shall occur not more
than one time per calendar year; provided, however, that the Purchaser may so visit
more frequently to the extent that there has occurred an event which could reasonably be expected
to result in a Material Adverse Effect, and the Purchaser’s visit or visits to Enzon’s offices in
connection therewith are for purposes related to such event.

     (d) All Audit Costs in respect of a License Party Audit requested by the Purchaser or an audit
of Enzon’s books and records pursuant to Section 5.07(c) shall be borne by the Purchaser, unless
the results of such audit, as the case may be, reveals that either (i) in any calendar year, the
Royalties that should have been paid by Schering to Enzon pursuant to the License Agreement are at
least five percent (5%) greater than those which were actually paid by Schering, or (ii) the
amounts paid to the Purchaser for the period subject to such audit have been understated by more
than the greater of $200,000 or five percent (5%) of the amounts due to the Purchaser pursuant to
this Agreement for the period subject to such audit, then in either case the Audit Costs in respect
of such audit shall be borne by Enzon.

     Section 5.08 Notice.

     Enzon shall provide the Purchaser with written notice as promptly as practicable (and in any
event within five (5) Business Days) after becoming aware of any of the following:

     (1) the occurrence of a Bankruptcy Event;

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     (2) any material breach or default by Enzon of any covenant, agreement or other
provision of this Agreement or any other Transaction Document; or

     (3) any representation or warranty made by Enzon in any of the Transaction Documents or
in any certificate delivered to the Purchaser pursuant hereto shall prove to be untrue,
inaccurate or incomplete in any material respect on the date as of which made,

with, in the case of clause (1) above, a copy to the Depositary Bank. In the event the Purchaser
has actual notice of the occurrence of a Bankruptcy Event, it shall be entitled to give written
notice thereof to the Depositary Bank, provided it concurrently delivers a copy thereof to
Enzon.

ARTICLE VI

THE CLOSING; CONDITIONS TO CLOSING

     Section 6.01 Closing.

     Subject to the closing conditions set forth in Sections 6.02 and 6.03, the closing of this
Agreement (the “Closing”) shall take place on August 22, 2007 or such other date as the
parties shall mutually agree (the “Closing Date”) at the offices of Heller Ehrman LLP, 7
Times Square, New York, New York, 10036.

     Section 6.02 Conditions Applicable to the Purchaser in Closing.

     The obligations of the Purchaser to effect the Closing, including the requirement to pay the
Initial Purchase Price pursuant to Section 2.03(a), shall be subject to the satisfaction of each of
the following conditions, on the Closing Date, any of which may be waived by the Purchaser in its
sole discretion:

     (a) Accuracy of Representations and Warranties. The representations and warranties of
Enzon set forth in the Transaction Documents that are qualified as to materiality or by Material
Adverse Effect shall be true, correct and complete, and those representations and warranties of
Enzon not so qualified shall be true, correct and complete in all material respects, in each case
as of the date hereof and as at Closing Date.

     (b) No Adverse Circumstances. There shall not have occurred or be continuing any
event or circumstance described in the definition of a Material Adverse Effect.

     (c) Litigation. No action, suit, litigation, proceeding or investigation shall have
been instituted, be pending or, to the Knowledge of Enzon, threatened (i) challenging or seeking to
make illegal, to delay or otherwise directly or indirectly to restrain or prohibit the consummation
of the transactions contemplated by this Agreement, or seeking to

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obtain damages in connection with the transactions contemplated by this Agreement, or (ii)
seeking to restrain or prohibit the Purchaser’s acquisition or future receipt of any or all of the
Purchased Interest.

     (d) Officer’s Certificate. The Purchaser shall have received a certificate of the
Chief Executive Officer of Enzon pursuant to which such officer certifies that the conditions set
forth in Sections 6.02(a), (b), (c), and (i) shall have been satisfied in all respects.

     (e) Bill of Sale and Receipt. A Bill of Sale in the form set forth in Exhibit
A, and a receipt in respect of that Bill of Sale in a form reasonably acceptable to the
Purchaser, shall have been executed and delivered by Enzon to the Purchaser, and the Purchaser
shall have received the same.

     (f) Deposit Agreement. The Deposit Agreement shall have been duly executed and
delivered by all parties thereto and shall be substantially in the form of Exhibit B.

     (g) Legal Opinions.

     (1) The Purchaser shall have received the opinions of Heller Ehrman LLP, transaction
counsel to Enzon, in form and substance satisfactory to the Purchaser and its counsel, to
the effect set forth in Exhibit C.

     (2) The Purchaser shall have received an opinion of Lucas & Mercanti LLP, patent
counsel to Enzon, in form and substance satisfactory to the Purchaser and its counsel, to
the effect set forth in Exhibit D.

     (h) Corporate Documents of Enzon. The Purchaser shall have received certificates of
an executive officer of Enzon (the statement made in which shall be true and correct on and as of
the Closing Date): (i) attaching copies, certified by such officer as true and complete, of
resolutions of the board of directors of Enzon authorizing and approving the execution, delivery
and performance by Enzon of the Transaction Documents and the transactions contemplated herein and
therein; (ii) setting forth the incumbency of the officer or officers of Enzon who have executed
and delivered the Transaction Documents including therein a signature specimen of each officer or
officers; and (iii) attaching copies, certified by such officer as true and complete, of long form
good standing certificates of the appropriate Governmental Authority of Enzon’s jurisdiction of
incorporation, stating that Enzon is in good standing under the laws of such jurisdiction.

     (i) Covenants. Enzon shall have complied in all material respects with its covenants
set forth in the Transaction Documents.

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     (j) Schering Letter. A copy of the letter in the form set forth in Exhibit E
shall have been signed and delivered by Enzon to the Purchaser, and the Purchaser shall have
received the same.

     (k) Other documents and financing statements. The Purchaser shall have received such
other certificates, documents and financing statements as the Purchaser may reasonably request,
including a financing statement satisfactory to the Purchaser to create, evidence and perfect the
sale of the Purchased Interest pursuant to Section 2.01(b) and the back-up security interest
granted pursuant to Section 2.01(c)

     Upon the Closing, the parties hereto acknowledge and agree that there shall be no closing
conditions to Purchaser’s satisfaction of its obligations under Section 2.03(b).

     Section 6.03 Conditions Applicable to Enzon in Closing.

     The obligations of Enzon to effect the Closing shall be subject to the satisfaction of each of
the following conditions on the Closing Date, any of which may be waived by Enzon in its sole
discretion:

     (a) Accuracy of Representations and Warranties. The representations and warranties of
the Purchaser set forth in this Agreement that are qualified as to materiality or by Material
Adverse Effect shall be true, correct and complete, and those representations and warranties of the
Purchaser not so qualified shall be true, correct and complete in all material respects, in each
case as of the date hereof and as at the Closing Date.

     (b) Litigation. No action, suit, litigation, proceeding or investigation shall have
been instituted, be pending or, to the knowledge of the Purchaser, threatened (i) challenging or
seeking to make illegal, to delay or otherwise directly or indirectly to restrain or prohibit the
consummation of the transactions contemplated by this Agreement, or seeking to obtain damages in
connection with the transactions contemplated by this Agreement, or (ii) seeking to restrain or
prohibit the Purchaser’s acquisition of any or all of the Purchased Interest.

     (c) Officer’s Certificate. Enzon shall have received at the Closing a certificate of
an authorized representative of the Purchaser certifying that the conditions set forth in Sections
6.03(a), (b) and (d) have been satisfied in all respects as of the Closing Date.

     (d) Covenants. The Purchaser shall have complied in all material respects with its
covenants set forth in the Transaction Documents.

     (e) Purchase Price. Enzon shall have received payment of the Initial Purchase Price
in accordance with Section 2.03(a).

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ARTICLE VII

EXPIRATION

     Section 7.01 Expiration Date.

     This Agreement shall terminate on the later of (i) the termination of the License Agreement
(or any amendment, or successor or replacement agreement thereto), or (ii) the date of expiration
of the last of the Patents Rights to expire for which a Valid Claim exists (including any patent
extension), provided that, notwithstanding the term of this Agreement, the Purchaser shall be
entitled to receive any payments relating to the Purchased Interest accruing on or prior to the
termination of this Agreement. This Agreement may be terminated by either party if the Closing has
not occurred on or before September 22, 2007, and the terminating party (a) in the case of Enzon,
has satisfied each of the conditions set forth in Section 6.02, and (b) in the case of the
Purchaser, has satisfied each of the conditions set forth in Section 6.03.

     Section 7.02 Effect of Expiration.

     In the event of the expiration of this Agreement pursuant to Section 7.01, this Agreement
shall forthwith become void and have no effect without any liability on the part of any party
hereto or its Affiliates, directors, officers, stockholders, managers or members other than the
provisions of this Section 7.02 and Sections 5.02, 8.01 and 8.05 hereof, which shall survive any
termination as set forth in Section 8.01. Nothing contained in this Section 7.02 shall relieve any
party from liability for any breach of this Agreement.

ARTICLE VIII

MISCELLANEOUS

     Section 8.01 Survival.

     (a) All representations and warranties made herein and in any other Transaction Document or
any certificates delivered pursuant to this Agreement shall survive the execution and delivery of
this Agreement and the Closing and shall continue to survive until the date that is eighteen (18)
months after the Closing Date; provided, however, that the representations and warranties contained
in Sections 3.01, 3.02, 3.04, 3.08, 3.10, 3.12, 3.13 and 3.14 shall survive until the expiration of
this Agreement; provided, further, however, that it is understood and agreed that notwithstanding
the survival provisions of this Section 8.01, all of the representations and warranties made by the
parties herein are made only as of the date of this Agreement and the Closing Date as provided in
Sections 6.02 and 6.03. Notwithstanding anything in this Agreement or implied by law to the
contrary, all of the agreements contained in Section 5.02, 8.01 and 8.05 shall survive indefinitely
following the execution and delivery of this Agreement and the Closing and the expiration of this
Agreement.

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     (b) Any investigation or other examination that may have been made or may be made at any time
by or on behalf of the party to whom representations and warranties are made shall not limit,
diminish or in any way affect the representations and warranties in the Transaction Documents, and
the parties may rely on the representations and warranties in the Transaction Documents
irrespective of any information obtained by them by any investigation, examination or otherwise.

     Section 8.02 Specific Performance.

     Each of the parties hereto acknowledges that the other party will have no adequate remedy at
law if it fails to perform any of its obligations under any of the Transaction Documents. In such
event, each of the parties agrees that the other party shall have the right, in addition to any
other rights it may have (whether at law or in equity), to specific performance of this Agreement.

     Section 8.03 Notices.

     All notices, consents, waivers and communications hereunder given by any party to the other
shall be in writing (including facsimile transmission) and delivered personally, by telegraph,
telecopy, telex or facsimile, by a recognized overnight courier, or by dispatching the same by
certified or registered mail, return receipt requested, with postage prepaid, in each case
addressed:

     If to the Purchaser to:

Drug Royalty LP 2

c/o Drug Royalty Corporation Inc.

Suite 3120, Royal Bank Plaza

Toronto, ON M5J 2J3

Canada

Attention: Behzad Khosrowshahi

Facsimile No.: (416) 863-5161

with a copy (which shall not constitute notice) to:

Cravath, Swaine & Moore LLP

Worldwide Plaza

825 Eighth Avenue

New York, NY 10019

United States

Attention: Joel F. Herold, Esq.

Facsimile No.: (212) 474-3700

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     If to Enzon:

Enzon Pharmaceuticals, Inc.

685 Route 202/206

Bridgewater, New Jersey

Attention: Chief Financial Officer

Facsimile No.: (908) 541-8838

     with a copy (which shall not constitute notice) to:

Heller Ehrman LLP

Times Square Tower

7 Times Square

New York, New York 10036-6524

Attention: Kevin Collins, Esq.

Facsimile No.: (212) 763-7600

or to such other address or addresses as the Purchaser or Enzon may from time to time designate by
notice as provided herein, except that notices of changes of address shall be effective only upon
receipt. All such notices consents, waivers and communications shall: (a) when posted by
certified or registered mail, postage prepaid, return receipt requested, be effective three (3)
Business Days after dispatch, unless such communication is sent trans-Atlantic, in which case shall
be deemed effective five (5) Business Days after dispatch, (b) when telegraphed, telecopied,
telexed or facsimiled, be effective upon receipt by the transmitting party of confirmation of
complete transmission, or (c) when delivered by a recognized overnight courier or in person, be
effective upon receipt when hand delivered.

     Section 8.04 Successors and Assigns.

     The provisions of this Agreement shall be binding upon and inure to the benefit of the parties
hereto and their respective successors and permitted assigns. Enzon shall not be entitled to
assign any of its obligations and rights under the Transaction Documents without the prior written
consent of the Purchaser; provided, however Enzon may, without the consent of the Purchaser, assign
any of its obligations or rights under the Transaction Documents to any other Person with which it
may merge or consolidate or to which it may sell all or substantially all of its assets or all of
its assets related to the Product, provided that the assignee under such assignment agrees to be
bound by the terms of the Transaction Documents. The Purchaser (or its successors and permitted
assigns) may assign or delegate all or any of its obligations and rights under the Transaction
Documents, without restriction and without the consent of Enzon: (i) by way of security to a
financial institution or other lender, (ii) to any Person that directly, or indirectly through one
or more intermediaries, controls or is controlled by, or is under

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common control with, the Purchaser, (iii) to a special purpose vehicle created to be
bankruptcy remote or for financing purposes or (iv) as part of a sale of a material part of the
Purchaser, in any case whether by way of reorganization or otherwise, and the Purchaser shall give
notice of any such assignment to Enzon after the occurrence thereof, provided that in each case,
the Purchaser will remain bound by and liable for the performance of its obligations under this
Agreement after such assignment has occurred; and further provided that Enzon shall be under no
obligation to reaffirm any representations, warranties or covenants made in this Agreement or any
of the other Transaction Documents or take any other action in connection with any such assignment
by the Purchaser.

     Section 8.05 Indemnification.

     (a) Enzon hereby indemnifies and holds each of the Purchaser and its Affiliates and any and
all of their respective partners, directors, managers, members, officers, employees and agents
(each a “Purchaser Indemnified Party”) harmless from and against any and all Losses
incurred or suffered by any Purchaser Indemnified Party arising out of: (i) any breach of any
representation, warranty or certification made by Enzon in any of the Transaction Documents or
certificates given by Enzon in writing pursuant hereto or thereto (ii) any breach of or default
under any covenant or agreement by Enzon pursuant to any Transaction Document, (iii) any Excluded
Liabilities and Obligations, and (iv) any fees, expenses or other payments incurred or owed by
Enzon to any brokers, financial advisors or comparable other persons retained or employed by it in
connection with the transactions contemplated by this Agreement.

     (b) The Purchaser hereby indemnifies and holds each of Enzon and its Affiliates and any of
their respective partners, directors, managers, officers, employees and agents (each an “Enzon
Indemnified Party”) harmless from and against any and all Losses incurred or suffered by an
Enzon Indemnified Party arising out of: (i) any breach of any representation, warranty or
certification made by the Purchaser in any of the Transaction Documents or certificates given by
the Purchaser in writing pursuant hereto or thereto, (ii) any breach of or default under any
covenant or agreement by the Purchaser pursuant to any Transaction Document and (iii) any fees,
expenses or other payments incurred or owed by the Purchaser to any brokers, financial advisors or
comparable other Persons retained or employed by it in connection with the transactions
contemplated by this Agreement.

     (c) If any claim, demand, action, or proceeding (including any investigation by any
Governmental Authority) shall be brought or alleged against an indemnified party in respect of
which indemnity is to be sought against an indemnifying party pursuant to the preceding paragraphs,
the indemnified party shall, promptly after receipt of notice of the commencement of any such
claim, demand, action or proceeding, notify the indemnifying party in writing of the commencement
of such claim, demand, action or

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proceeding, enclosing a copy of all papers served, if any; provided, that, the omission to so
notify such indemnifying party will not relieve the indemnifying party from any liability that it
may have to any indemnified party under the foregoing provisions of this Section 8.05 unless, and
only to the extent that, such omission results in the forfeiture of, or have a material adverse
effect on the exercise or prosecution of, substantive rights or defenses by the indemnifying party.
In case any such action is brought against an indemnified party and it notifies the indemnifying
party of the commencement thereof, the indemnifying party will be entitled to participate therein
and, to the extent that it may wish, to assume the defense thereof, with counsel reasonably
satisfactory to such indemnified party (who shall not, except with the consent of the indemnified
party, be counsel to the indemnifying party), and after notice from the indemnifying party to such
indemnified party of its election so to assume the defense thereof, the indemnifying party will not
be liable to such indemnified party under this Section 8.05 for any legal or other expenses
subsequently incurred by such indemnified party in connection with the defense thereof other than
reasonable costs of investigation. In any such proceeding, an indemnified party shall have the
right to retain its own counsel, but the reasonable fees and expenses of such counsel shall be at
the expense of such indemnified party unless (i) the indemnifying party and the indemnified party
shall have mutually agreed to the retention of such counsel, (ii) the indemnifying party has
assumed the defense of such proceeding and has failed within a reasonable time to retain counsel
reasonably satisfactory to such indemnified party or (iii) the named parties to any such proceeding
(including any impleaded parties) include both the indemnifying party and the indemnified party and
representation of both parties by the same counsel would be inappropriate due to actual or
potential conflicts of interests between them based on the advice of counsel to the indemnifying
party. It is agreed that the indemnifying party shall not, in connection with any proceeding or
related proceedings in the same jurisdiction, be liable for the reasonable fees and expenses of
more than one separate law firm (in addition to local counsel where necessary) for all such
indemnified parties. The indemnifying party shall not be liable for any settlement of any
proceeding effected without its written consent, but if settled with such consent or if there be a
final judgment for the plaintiff, the indemnifying party agrees to indemnify the indemnified party
from and against any loss or liability by reason of such settlement or judgment. No indemnifying
party shall, without the prior written consent of the indemnified party, effect any settlement of
any pending or threatened proceeding in respect of which any indemnified party is or could have
been a party and indemnity could have been sought hereunder by such indemnified party, unless such
settlement includes an unconditional release of such indemnified party from all liability on claims
that are the subject matter of such proceeding.

     (d) No claim for indemnification hereunder for breach of any representations or warranties
contained in any Transaction Document may be made after the expiration of the survival period
applicable to such representation or warranty; provided that any

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written claim for breach thereof made prior to such expiration date and delivered to the party
against whom such indemnification is sought shall survive thereafter with respect to such claim.

     (e) Following Closing, the indemnification afforded by this Section 8.05 shall be the sole and
exclusive remedy for any and all Losses sustained or incurred by a party hereto in connection with
the transactions contemplated by the Transaction Documents, including with respect to any breach of
any representation, warranty or certification made by a party hereto in any of the Transaction
Documents or certificates given by a party in writing pursuant hereto or thereto or any breach of
or default under any covenant or agreement by a party pursuant to any Transaction Document.
Notwithstanding anything herein to the contrary, in no event shall Losses include any
consequential, lost profits or punitive damages. Notwithstanding the foregoing, in the event of
any breach or failure in performance of any covenant or agreement contained in any Transaction
Document, the non-breaching party shall be entitled to seek specific performance, injunctive or
other equitable relief. For clarity, neither party shall have any right to terminate this
Agreement or any other Transaction Document after the Closing as a result of any breach by the
other party hereof or thereof, but instead shall have the right to seek indemnification under this
Section 8.05 and such specific performance.

     Section 8.06 Independent Nature of Relationship.

     (a) The relationship between Enzon and the Purchaser is solely that of seller and purchaser,
and neither the Purchaser nor Enzon has any fiduciary or other special relationship with the other
or any of their respective Affiliates. Nothing contained herein or in any other Transaction
Document shall be deemed to constitute Enzon and the Purchaser as a partnership, an association, a
joint venture or other kind of entity or legal form.

     (b) No officer or employee of the Purchaser will be located at the premises of Enzon or any of
its Affiliates, except in connection with an audit performed pursuant to Section 5.07. No officer,
manager or employee of the Purchaser shall engage in any commercial activity with Enzon or any of
its Affiliates other than as contemplated herein and in the other Transaction Documents.

     (c) Enzon and/or any of its Affiliates shall not at any time obligate the Purchaser, or impose
on the Purchaser any obligation, in any manner or respect to any Person not a party hereto.

     Section 8.07 Tax.

     (a) Notwithstanding the accounting treatment thereof, for United States federal, state and
local tax purposes, Enzon and the Purchaser shall treat the transactions contemplated by the
Transaction Documents as a sale for United States tax purposes.

- 34 -

 

     (b) To the extent any tax is withheld at source from a payment made pursuant to the License
Agreement, and such withheld tax is determined without regard to this Agreement (i.e., on the basis
that Enzon is the sole beneficial owner of the Royalties), such withheld tax shall for all purposes
of this Agreement be treated as paid to Enzon and the Purchaser on a pro rata basis in accordance
with each of the party’s underlying ownership interest in each such payment (taking into account
any taxes withheld); e.g., with respect to the Purchaser, taxes so withheld shall be attributed to
the Purchaser, and deemed paid to the Purchaser, in accordance with the Purchased Interest. To the
extent any tax is withheld at source from a payment made pursuant to the License Agreement, and
such withheld tax is determined on the basis that Enzon and Purchaser is each the beneficial owner
of its respective economic interest in the Royalties, such withheld tax shall for all purposes of
this Agreement be allocated between Enzon and the Purchaser based on the respective taxes required
to be withheld on the Royalties allocable to each of them. Any taxes withheld pursuant to this
Section 8.07(b) attributable to the Purchaser shall be credited for the account of the Purchaser.
Neither party shall have any obligation to gross-up or otherwise pay the other party any amounts
with respect to source withholding tax. All taxes withheld at source as described herein shall for
all purposes of this Agreement (including Section 8.07(c)) be deemed to have been received by the
party to which they are attributed as provided above or to which the payment subject to such
withholding tax was made.

     (c) The parties hereto agree not to take any position that is inconsistent with the provisions
of this Section 8.07 on any tax return or in any audit or other administrative or judicial
proceeding unless (i) the other party to this Agreement has consented to such actions, or (ii) the
party that contemplates taking such an inconsistent position has been advised by counsel in writing
that there is no “reasonable basis” (within the meaning of Treasury Regulation Section
1.6662-3(b)(3)) for the position specified in this Section 8.07. If there is an inquiry by any
Governmental Authority of Enzon or the Purchaser related to this Section 8.07, the parties shall
cooperate with each other in responding to such inquiry in a reasonable manner consistent with this
Section 8.07.

     Section 8.08 Entire Agreement.

     This Agreement, together with the Exhibits and Schedules hereto (which are incorporated herein
by reference), and the other Transaction Documents constitute the entire agreement between the
parties with respect to the subject matter hereof and supersede all prior agreements,
understandings and negotiations, both written and oral, between the parties with respect to the
subject matter of this Agreement. No representation, inducement, promise, understanding, condition
or warranty not set forth herein (or in the Exhibits, Schedules or other Transaction Documents) has
been made or relied upon by either party hereto. Neither this Agreement, nor any provision hereof,
is intended to confer upon any Person other than the parties hereto any rights or remedies
hereunder.

- 35 -

 

     Section 8.09 Governing Law.

     (a) This Agreement shall be construed in accordance with and governed by the laws of the State
of New York, without giving effect to the principles of conflicts of law thereof.

     (b) Each of the parties hereby irrevocably and unconditionally submits, for itself and its
property, to the nonexclusive jurisdiction of the Supreme Court of the State of New York sitting in
New York County and of the United States District Court of the Southern District of New York, and
any appellate court from any thereof, in any action or proceeding arising out of or relating to
this Agreement, or for recognition or enforcement of any judgment, and each of the parties hereto
hereby irrevocably and unconditionally agrees that all claims in respect of any such action or
proceeding may be heard and determined in such New York State or, to the extent permitted by law,
in such Federal court. Each of the parties hereto agrees that a final judgment in any such action
or proceeding shall be conclusive and may be enforced in other jurisdictions by suit on the
judgment or in any other manner provided by law. Nothing in this Agreement shall affect any right
that a party may otherwise have to bring any action or proceeding relating to this Agreement
against another party or its properties in the courts of any jurisdiction.

     (c) Each of the parties hereby irrevocably and unconditionally waives, to the fullest extent
it may legally and effectively do so, any objection which it may now or hereafter have to the
laying of venue of any suit, action or proceeding arising out of or relating to this Agreement in
any court referred to in paragraph (b) of this Section. Each of the parties hereto hereby
irrevocably waives, to the fullest extent permitted by law, the defense of an inconvenient forum to
the maintenance of such action or proceeding in any such court.

     (d) Each party to this Agreement irrevocably consents to service of process in the manner
provided for notices in Section 8.03. Nothing in this Agreement will affect the right of any party
to this Agreement to serve process in any other manner permitted by law.

     Section 8.10 Waiver of Jury Trial

     EACH PARTY HERETO HEREBY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT
IT MAY HAVE TO A TRIAL BY JURY IN ANY LEGAL PROCEEDING DIRECTLY OR INDIRECTLY ARISING OUT OF OR
RELATING TO THIS AGREEMENT, OR THE TRANSACTIONS CONTEMPLATED HEREBY (WHETHER BASED ON CONTRACT,
TORT OR ANY OTHER THEORY). EACH PARTY HERETO (A) CERTIFIES THAT NO REPRESENTATIVE, AGENT OR
ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD
NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER AND (B) ACKNOWLEDGES THAT IT
AND THE OTHER

- 36 -

 

PARTIES HERETO HAVE BEEN INDUCED TO ENTER INTO THIS AGREEMENT BY, AMONG OTHER THINGS, THE
MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION.

     Section 8.11 Severability.

     If one or more provisions of this Agreement are held to be unenforceable under applicable law,
such provision shall be excluded from this Agreement and the balance of the Agreement shall be
interpreted as if such provision were so excluded and shall be enforceable in accordance with its
terms.

     Section 8.12 Counterparts; Effectiveness.

     This Agreement may be signed in any number of counterparts, each of which shall be an
original, with the same effect as if the signatures thereto and hereto were upon the same
instrument. This Agreement shall become effective when each party hereto shall have received a
counterpart hereof signed by the other party hereto. Any counterpart may be executed by facsimile
signature and such facsimile signature shall be deemed an original.

     Section 8.13 Amendments; No Waivers.

     (a) This Agreement or any term or provision hereof may not be amended, changed or modified
except with the written consent of the parties hereto. No waiver of any right hereunder shall be
effective unless such waiver is signed in writing by the party against whom such waiver is sought
to be enforced.

     (b) No failure or delay by either party in exercising any right, power or privilege hereunder
shall operate as a waiver thereof nor shall any single or partial exercise thereof preclude any
other or further exercise thereof or the exercise of any other right, power or privilege. The
rights and remedies herein provided shall be cumulative and not exclusive of any rights or remedies
provided by law.

     Section 8.14 Interpretation.

     When a reference is made in this Agreement to Sections, Exhibits or Schedules, such reference
shall be to a Section, Exhibit or Schedule to this Agreement unless otherwise indicated. In this
Agreement, words in the singular include the plural and vice-versa and words in gender include all
genders. The words “include,” “includes” and “including” when used herein shall be deemed in each
case to be followed by the words “without limitation” and shall not be construed to limit any
general statement which it follows to the specific or similar items or matters immediately
following it. Neither party hereto shall be or be deemed to be the drafter of this Agreement for
the purposes of construing this Agreement against one party or the other.

- 37 -

 

[Signature page follows]

- 38 -

 

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly executed by their
respective authorized officers as of the date first above written.

	 	 	 	 	 	 	 
	 	 	ENZON PHARMACEUTICALS, INC.	 	 
	 
	 	 	 	 	 	 
	 

	 	By:	 	 	 	 
	 

	 	 	 	 	 	 
	 	 	Name: Jeffrey H. Buchalter	 	 
	 	 	Title:   Chairman, President and	 	 
	 

	 	 	 	    Chief Executive Officer	 	 
	 
	 	 	 	 	 	 
	 	 	DRUG ROYALTY LP2	 	 
	 
	 	 	 	 	 	 
	 

	 	By:	 	 	 	 
	 

	 	 	 	 	 	 
	 	 	Name:	 	 
	 	 	Title:	 	 

 

 

EXHIBITS AND SCHEDULES

     EXHIBITS

Exhibit A — Form of Bill of Sale

Exhibit B — Form of Deposit Agreement

Exhibit C — Form of Legal Opinions of Heller Ehrman LLP (transaction counsel)

Exhibit D — Form of Legal Opinion of Lucas & Mercanti, LLP (patent counsel)

Exhibit E — Form of Letter to Schering

     SCHEDULES

Schedule 3.10(a) — Patent Rights

Schedule 5.02 — Form of Press Release

 

 

EXHIBIT A

FORM OF BILL OF SALE

 

 

EXHIBIT B

FORM OF DEPOSIT AGREEMENT

B-1 

 

EXHIBIT C

FORM OF LEGAL OPINIONS

OF HELLER EHRMAN LLP (TRANSACTION COUNSEL)

C-1 

 

EXHIBIT D

FORM OF LEGAL OPINION

OF LUCAS & MERCANTI LLP (PATENT COUNSEL)

D-1 

 

EXHIBIT E

FORM OF LETTER TO SCHERING

E-1 

 

SCHEDULE 3.10(a)

PATENT RIGHTS

	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
	 	 	 	 	COUNTRY/	 	 	 	 	 	 	 	 	 	 
	TITLE Exp.	 	INVENTOR	 	REGION	 	FILED	 	 	SERIAL No.	 	 	PATENT No.	 	 	ISSUED	 	YR	 
	Active Carbonates of
Polyalkylene Oxides for Modification
of Polypetides

	 	Zalipsky	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
	

	 	 	 	United States
	 	04/19/90
	 	 	511,243	 	 	5,122,614	 	 	06/16/92
	 	6/2009	 
	

	 	 	 	United States
	 	01/08/92
	 	 	07/817,757	 	 	5,324,844	 	 	06/28/94
	 	6/2009	 
	

	 	 	 	United States
	 	02/17/94
	 	 	08/198,193	 	 	5,612,460	 	 	03/18/97
	 	3/2014	 
	

	 	 	 	United States
	 	01/21/97
	 	 	08/785,320	 	 	5,808,096	 	 	09/15/98
	 	4/2009	 
	 

	 	 	 	Austria
	 	04/19/90
	 	 	90906698.7	 	 	0470128	 	 	06/30/99
	 	4/2010	 
	 

	 	 	 	Belgium
	 	04/19/90
	 	 	90906698.7	 	 	0470128	 	 	06/30/99
	 	4/2010	 
	 

	 	 	 	Switzerland
	 	04/19/90
	 	 	90906698.7	 	 	0470128	 	 	06/30/99
	 	4/2010	 
	 

	 	 	 	Germany
	 	04/19/90
	 	 	90906698.7	 		P69033192.4	 	 	06/30/99
	 	4/2010	 
	 

	 	 	 	Denmark
	 	04/19/90
	 	 	90906698.7	 	 	0470128	 	 	06/30/99
	 	4/2010	 
	 

	 	 	 	Spain
	 	04/19/90
	 	 	90906698.7	 	 	8802307/9	 	 	06/16/99
	 	4/2010	 
	 

	 	 	 	France
	 	04/19/90
	 	 	90906698.7	 	 	0470128	 	 	06/62/99
	 	4/2010	 
	 

	 	 	 	Italy
	 	04/19/90
	 	 	90906698.7	 	 	0470128	 	 	06/30/99
	 	4/2010	 
	 

	 	 	 	Luxembourg
	 	04/19/90
	 	 	90906698.7	 	 	0470128	 	 	06/30/99
	 	4/2010	 
	 

	 	 	 	Netherlands
	 	04/19/90
	 	 	90906698.7	 	 	0470128	 	 	06/30/99
	 	4/2010	 
	 

	 	 	 	Sweden
	 	04/19/90
	 	 	90906698.7	 	 	0470128	 	 	06/30/99
	 	4/2010	 
	 

	 	 	 	United Kingdom
	 	04/19/90
	 	 	90906698.7	 	 	0470128	 	 	06/30/99
	 	4/2010	 
	 

	 	 	 	Canada
	 	04/19/90
	 	 	2,053,317	 	 	2,053,317	 	 	03/12/96
	 	4/2010	 
	 

	 	 	 	Japan
	 	04/19/90
	 	 	2-506500	 	 	2875884	 	 	01/14/99
	 	4/2010	 
	 
	SUMMARY: PEG-SC; bis-activated PEG; methods of making PEG-SC, product by process,
	 
	Improved
Interferon Polymer Conjugates
	 	Gilbert, Cho	 	United States	 	11/10/94	 	 	08/337,567	 	 	5,711,944	 	 	01/27/98	 	1/2015	 
	 
	 	 	 	United States	 	12/19/97	 	 	08/994,622	 	 	5,951,974	*	 	09/14/99	 	1/2015	*
	 
	 	 	 	United States	 	04/06/99	 	 	09/287,476	 	 	6,042,822	 	 	03/28/00	 	11/2013	 
	 
	 	 	 	Canada	 	11/10/94	 	 	2,176,229	 	 	2,176,229	 	 	05/27/03	 	11/2014	 
	 
	 	 	 	Austria	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Belgium	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Switzerland	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Germany	 	11/10/94	 	 	95902571.9	 	 	69430251.1	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Denmark	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Spain	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	France	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	United Kingdom	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Greece	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Ireland	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Italy	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Luxembourg	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Monaco	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 
	 
	 	 	 	Netherlands	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	11/2014	 

 

 

	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 
	 	 	 	 	COUNTRY/	 	 	 	 	 	 	 	 	 	 	 
	TITLE Exp.	 	INVENTOR	 	REGION	 	FILED	 	 	SERIAL No.	 	 	PATENT No.	 	 	ISSUED	 	 	YR	 
	 
	 	 	 	Portugal	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	 	11/2014	 
	 
	 	 	 	Sweden	 	11/10/94	 	 	95902571.9	 	 	0730470	 	 	03/27/02	 	 	11/2014	 
	 
	 	 	 	Canada	 	12/16/98	 	 	2,268,433	 	 	2,268,433	 	 	07/30/02	 	 	12/2018	 
	 
	 	 	 	Austria	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Belgium	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Switzerland	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Cyprus	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Germany	 	12/16/98	 	 	98963947.1	 	 	69806055.5	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Denmark	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Spain	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Finland	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	France	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	United Kingdom	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Greece	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Ireland	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Italy	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Lithuania	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Luxembourg	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Latvia	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Monaco	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Netherlands	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Portugal	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Romania	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Sweden	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Slovenia	 	12/16/98	 	 	98963947.1	 	 	1 039 922	 	 	06/12/02	 	 	12/2018	 
	 
	 	 	 	Japan	 	12/16/98	 	 	11-533967	 	 	3747070	 	 	02/22/06	 	 	12/2018	 
	 
	 	 	 	Japan	 	12/16/98	 	 	2004-124019	 	 	 	 	 	 	 	 	 	 
	 
	 	 	 	Mexico	 	12/16/98	 	 	9911862	 	 	239653	 	 	08/22/06	 	 	12/2018	 

SUMMARY: *PEG-Interferon; methods of making; positional isomers

‘944

1. A process for preparing a long-acting alpha-interferon-containing composition, comprising
contacting an alpha interferon with from about a 1 to about an 8-fold molar excess of an activated
polyalkylene oxide containing an alkyl terminal in the presence of a surfactant under conditions
sufficient to form conjugates of said alpha interferon and said polyalkylene oxide having an alkyl
terminal and thereafter fractionating the conjugates to isolate the conjugates containing about 1-4
polyalkylene oxide strands per alpha-interferon molecule.

**************

‘974

1. A pharmaceutical composition, comprising a mixture of alpha interferon polymer conjugate
positional isomers, wherein one of said positional isomers comprises an alpha interferon covalently
conjugated to a substantially non-antigenic polymer at a histidine residue on said alpha
interferon, wherein said substantially non-antigenic polymer is a polyalkylene oxide comprising an
alkyl terminal. *Product claims; patent term extension 435 days; exp. date 1/19/2015

*********

‘822

 

 

1. A pharmaceutical composition, comprising a mixture of alpha-interferon-conjugate positional
isomers, wherein one of said positional isomers comprises an alpha-interferon covalently conjugated
to a substantially non-antigenic alkyl terminated polyalkylene oxide at a histidine residue on said
alpha interferon, so that said alpha interferon
conjugates have a Tmax at least about 4 times greater than unmodified alpha-interferon
measured under the same conditions.

 

 

SCHEDULE 5.02

FORM OF PRESS RELEASE

			
	
	 	For Immediate Release

	 	 	 	 	 
	 

	 	Contact:
	 	Craig Tooman
	 

	 	 	 	EVP, Finance and Chief
	 

	 	 	 	Financial Officer
	 

	 	 	 	908-541-8777

ENZON TO ELIMINATE ITS REMAINING 2008 CONVERTIBLE DEBT

—Company monetizes a portion of its PEG-INTRON royalty stream for $92.5MM—

BRIDGEWATER, NJ — August 20, 2007 — Enzon Pharmaceuticals, Inc. (Nasdaq: ENZN) today announced the
sale of a 25% interest in its royalty from PEG-INTRON®, marketed by Schering-Plough
Corporation for $92.5 million to Drug Royalty Corporation, Inc. (DRC). Enzon is also entitled to
receive an additional one-time milestone payment of $15 million in 2012 should certain royalty
recognition levels be met for PEG-INTRON. A portion of the proceeds will be used for retirement in
full of Enzon’s outstanding 4.5% Convertible Notes due 2008. Enzon will retain a 75% interest in
the PEG-INTRON royalty, as well as 100% of their other current royalties and any new royalties the
company receives.

To date, Enzon has already reduced the outstanding amount of its 2008 convertible debt to $81.9
million through a series of successful open market repurchases at a discount to par.

“Today’s announcement is a result of a thorough and comprehensive evaluation of our options to
extinguish our debt due in 2008,” said Jeffrey H. Buchalter, chairman and chief executive officer
of Enzon. “This transaction now fully removes any risk associated with repayment of the 2008
convertible note, and allows Enzon to continue to focus on its goal of building an innovative
oncology company.”

Currently, Enzon earns royalties on three marketed products that are successfully utilizing Enzon’s
proprietary PEGylation platform, namely PEG-INTRON, Pegasys, and Macugen.

PEG-INTRON is a PEG-enhanced version of Schering-Plough’s alpha interferon product,
INTRON® A, which is used both as a monotherapy and in combination with
REBETOL® (ribavirin) capsules for the treatment of chronic hepatitis C. Under our
license agreement with Schering-Plough, Schering-

 

 

Plough holds an exclusive worldwide license to
PEG-INTRON, and Enzon receives royalties on worldwide sales of PEG-INTRON. Schering-Plough is
responsible for all manufacturing, marketing,
and development activities for PEG-INTRON. Enzon designed PEG-INTRON to allow for less frequent
dosing and to yield greater efficacy, as compared to INTRON A. PEG-INTRON is marketed worldwide by
Schering-Plough and its affiliates.

About Enzon

Enzon Pharmaceuticals, Inc. is a biopharmaceutical company dedicated to the development,
manufacturing, commercialization of important medicines for patients with cancer and other
life-threatening conditions. Enzon has a portfolio of four marketed products, Oncaspar®,
DepoCyt®, Abelcet® and Adagen®. The Company’s drug development
programs utilize several cutting-edge approaches, including its industry-leading PEGylation
technology platform used to create product candidates with benefits such as reduced dosing
frequency and less toxicity. Enzon’s PEGylation technology was used to develop two of its products,
Oncaspar and Adagen, and has created a royalty revenue stream from licensing partnerships for other
products developed using the technology. Enzon also engages in contract manufacturing for several
pharmaceutical companies to broaden the Company’s revenue base. Further information about Enzon and
this press release can be found on the Company’s web site at www.enzon.com.

About Drug Royalty Corporation, Inc. (DRC)

Drug Royalty Corporation (“DRC”) is a privately held investment management company, focused on the
healthcare industry, with over $1 billion under management. DRC currently manages two funds: the
Royalty Monetization Fund and the Structured Finance Fund.

Its Royalty Monetization Fund acquires existing royalty streams at competitive rates from
companies, institutions and inventors. DRC is a leader in monetizing royalties, having acquired
over $750 million in royalty-based cash flows on commercialized products. Its Structured Finance
Fund will soon close with approximately $300 million in committed capital. This Fund provides
predominantly non-dilutive financing for product acquisitions and launches, M & A, in-licensing,
sales force expansion and general working capital purposes to companies within the healthcare
industry. The Fund invests in cash flow monetization structures which can include debt and equity
components, custom tailored to fit the needs of clients.

Forward Looking Statements

There are forward-looking statements contained herein, which can be identified by the use of
forward-looking terminology such as the words “believes,” “expects,” “may,” “will,” “should”,
“potential,” “anticipates,” “plans” or “intends” and similar expressions. Such forward-looking
statements involve known and unknown risks, uncertainties and other factors that may cause actual
results, events or developments to be materially different from the future results, events or
developments indicated in such forward-looking statements. Such factors include, but are not
limited to the timing, success and cost of clinical studies; the ability to obtain regulatory
approval of products, market acceptance of, and continuing demand for, Enzon’s products and the
impact of competitive products and pricing. A more detailed discussion of these and other factors
that could affect results is contained in our filings with the U.S. Securities and Exchange
Commission, including our annual report on Form 10-K for the year ended December 31, 2006

 

 

and our
quarterly reports on Form 10-Q. These factors should be considered
carefully and readers are cautioned not to place undue reliance on such forward-looking statements.
No assurance can be given that the future results covered by the forward-looking statements will
be achieved. All information in this press release is as of the date of this press release and
Enzon does not intend to update this information.

685 Route 202/206

Phone: (908) 541-8600 Fax: (908) 575-9457

http://www.enzon.com

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