<PAGE>
                                                                     EXHIBIT 4.7

      THIS WARRANT AND THE SECURITIES ISSUABLE UPON THE EXERCISE HEREOF HAVE NOT
      BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"),
      OR ANY STATE SECURITIES LAWS. THEY MAY NOT BE SOLD, OFFERED FOR SALE,
      PLEDGED, HYPOTHECATED OR OTHERWISE TRANSFERRED IN THE ABSENCE OF A
      REGISTRATION STATEMENT IN EFFECT WITH RESPECT TO THE SECURITIES UNDER SUCH
      ACT OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE COMPANY THAT
      SUCH REGISTRATION IS NOT REQUIRED OR UNLESS SOLD PURSUANT TO AN EXEMPTION
      TO SUCH ACT.

                                                                      Void after
                                                                  April 30, 2008

                           WARRANT TO PURCHASE SHARES
                                 OF COMMON STOCK
                                       OF
                                 SANTARUS, INC.

      This certifies that, for value received, Rockport Venture Securities, LLC,
together with its successors and assigns (the "Holder") is entitled to subscribe
for and purchase, on the terms hereof, shares of Common Stock (the "Common
Stock") of Santarus, Inc., a Delaware corporation (the "Company"), subject to
adjustment as provided herein.

      This Warrant is subject to the following terms and conditions:

      1. Exercise of Warrant. The terms and conditions upon which this Warrant
may be exercised, and the Common Stock covered hereby (the "Warrant Stock") may
be purchased, are as follows:

            1.1 Term. Subject to the terms hereof, this Warrant may be exercised
at any time after the date hereof, or from time to time, in whole or in part;
provided, however, that in no event may this Warrant be exercised (the "Exercise
Date") later than 5:00 p.m. (Pacific Time) on the earlier of (a) the close of
business on April 30, 2008 or (b) the closing of a Corporate Transaction (as
defined below) (the "Exercise Period"). At least twenty (20) days prior to the
occurrence of the closing of a Corporate Transaction, the Company shall send to
the Holder notice of such event.

            For purposes hereof, the term "Corporate Transaction" shall mean (a)
the sale, conveyance, disposal, or encumbrance of all or substantially all of
the Company's property or business; or (b) the Company's merger into or
consolidation with any other corporation (other than a wholly-owned subsidiary
corporation or a merger effected exclusively for the purpose of changing the
domicile of the Company) or any other transaction or series of transactions, in
which more than fifty percent (50%) of the voting power of the Company is
disposed of (other than a sale by the Company of shares of its capital stock in
an equity financing).

            1.2 Number of Shares. This Warrant may be exercised for 71,673
shares of Common Stock, subject to adjustment as provided herein.
<PAGE>
            1.3 Exercise Price. The per share exercise price for the shares of
Common Stock to be issued upon exercise of this Warrant shall be $1.2557,
subject to adjustment as provided herein (such price as adjusted from time to
time as provided herein is called the "Exercise Price").

            1.4 Method of Exercise. The exercise of the purchase rights
evidenced by this Warrant shall be effected by (a) the surrender of the Warrant,
together with a duly executed copy of the form of a subscription attached hereto
as Schedule 1, to the Company at its principal offices and (b) the delivery of
the aggregate Exercise Price by check or bank draft payable to the Company's
order or by wire transfer to the Company's account for the number of shares for
which the purchase rights hereunder are being exercised or any other form of
consideration approved by the Company's Board of Directors (the "Board"). Each
exercise of this Warrant shall be deemed to have been effected immediately prior
to the close of business on the day on which this Warrant shall have been
surrendered to the Company as provided herein or at such later date as may be
specified in the executed form of subscription, and at such time the person or
persons in whose name or names any certificate or certificates for shares of
Common Stock shall be issuable upon such exercise as provided herein shall be
deemed to have become the holder or holders of record thereof.

            1.5 Net Issuance.

                  (a) Right to Convert. In addition to and without limiting the
rights of the Holder under the terms of this Warrant, the Holder shall have the
right to convert this Warrant or any portion thereof (the "Conversion Right")
into shares of Common Stock as provided in this Section 1.5 at any time or from
time to time during the Exercise Period. Upon exercise of the Conversion Right
with respect to a particular number of shares subject to the Warrant (the
"Converted Warrant Shares"), the Company shall deliver to the Holder (without
payment by the Holder of any exercise price or any cash or other consideration)
that number of shares of fully paid and nonassessable Common Stock computed
using the following formula:

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

             Where       X= the number of shares of Common Stock to be delivered
                            to the Holder
                         Y= the number of Converted Warrant Shares
                         A= the per share fair market value of the Common Stock
                         on the Conversion Date (as defined below)
                         B= the Exercise Price (as adjusted to the
                            Conversion Date)

      The Conversion Right may only be exercised with respect to a whole number
of shares subject to the Warrant. No fractional shares shall be issuable upon
exercise of the Conversion Right, and if the number of shares to be issued
determined in accordance with the foregoing formula is other than a whole
number, the Company shall pay to the Holder an amount in cash equal to the fair
market value of the resulting fractional share on the Conversion Date (as
defined below). Shares issued pursuant to the Conversion Right shall be treated
as if they were issued upon the exercise of the Warrant.

                  (b) Method of Exercise. The Conversion Right may be exercised
by the Holder by the surrender of the Warrant at the principal office of the
Company together with a



                                       2
<PAGE>
notice in the form attached hereto as Schedule 2 specifying that the Holder
thereby intends to exercise the Conversion Right and indicating the total number
of shares under the Warrant that the Holder is exercising through the Conversion
Right. Such conversion shall be effective upon receipt by the Company of the
Warrant together with the aforesaid written statement, or on such later date as
is specified therein (the "Conversion Date"). Certificates for the shares
issuable upon exercise of the Conversion Right and, if applicable, a new warrant
evidencing the balance of the shares remaining subject to the Warrant, shall be
issued as of the Conversion Date and shall be delivered to the Holder promptly
following the Conversion Date.

                  (c) Determination of Fair Market Value. For purposes of this
Section 1.5, fair market value of a share of Common Stock on the Conversion Date
shall mean the fair market value as determined by the Board.

      2. Adjustment of Exercise Price and Number of Shares. The Exercise Price
and the number of shares purchasable upon the exercise of this Warrant shall be
subject to adjustment from time to time upon the occurrence of certain events
described in this Section 2. Upon each adjustment of the Exercise Price, the
Holder of this Warrant shall thereafter be entitled to purchase, at the Exercise
Price resulting from such adjustment, the number of shares obtained by
multiplying the Exercise Price in effect immediately prior to such adjustment by
the number of shares purchasable pursuant hereto immediately prior to such
adjustment, and dividing the product thereof by the Exercise Price resulting
from such adjustment.

            2.1 Subdivision or Combination of Common Stock. In case the Company
shall at any time subdivide its outstanding shares of Common Stock into a
greater number of shares, the Exercise Price in effect immediately prior to such
subdivision shall be proportionately reduced, and conversely, in case the
outstanding shares of Common Stock of the Company shall be combined into a
smaller number of shares, the Exercise Price in effect immediately prior to such
combination shall be proportionately increased.

            2.2 Dividends in Common Stock, Other Stock, Property,
Reclassification. If at any time or from time to time the holders of Common
Stock (or any shares of stock or other securities at the time receivable upon
the exercise of this Warrant) shall have received or become entitled to receive,
without payment therefor,

                  (a) Common Stock, or any shares of stock or other securities
whether or not such securities are at any time directly or indirectly
convertible into or exchangeable for Common Stock, or any rights or options to
subscribe for, purchase or otherwise acquire any of the foregoing by way of
dividend or other distribution, or

                  (b) any cash paid or payable otherwise than as a cash
dividend, or

                  (c) Common Stock or other or additional stock or other
securities or property (including cash) by way of spin off, split-up,
reclassification, combination of shares or similar corporate rearrangement,
(other than shares of Common Stock issued as a stock split, adjustments in
respect of which shall be covered by the terms of Section 2.1 above),

      Then and in each such case, the Holder hereof shall, upon the exercise of
this Warrant, be entitled to receive, in addition to the number of shares of
Common Stock receivable thereupon, and without payment of any additional
consideration therefore, the amount of stock and other



                                       3
<PAGE>
securities and property (including cash in the cases referred to in clauses (b)
and (c) above) which such Holder would hold on the date of such exercise had he
been the holder of record of such Common Stock as of the date on which holders
of Common Stock received or became entitled to receive such shares and/or all
other additional stock and other securities and property.

            2.3 Reclassification or Reorganization. If the Common Stock (or any
shares of stock or other securities which may be) issuable upon the exercise of
this Warrant shall be changed into the same or different number of shares of any
class or classes of stock, whether by capital reorganization, reclassification
or otherwise (other than a subdivision or combination of shares or stock
dividend provided for in Section 2.1 above, or a Corporate Transaction, in which
case this Warrant shall terminate if not exercised), then and in each such event
the Holder shall be entitled to receive upon the exercise of this Warrant the
kind and amount of shares of stock and other securities and property receivable
upon such reorganization, reclassification or other change, to which a holder of
the number of shares of Common Stock (or any shares of stock or other securities
which may be) issuable upon the exercise of this Warrant would have received if
this Warrant had been exercised immediately prior to such reorganization,
reclassification or other change, all subject to further adjustment as provided
herein.

            2.4 Notice of Adjustments and Record Dates. The Company shall
promptly notify the Holder in writing of each adjustment or readjustment of the
exercise price hereunder and the number of shares of Common Stock (or any shares
of stock or other securities which may be) issuable upon the exercise of this
Warrant. Such notice shall state the adjustment or readjustment and show in
reasonable detail the facts on which that adjustment or readjustment is based.
In the event of any taking by the Company of a record of the holders of Common
Stock for the purpose of determining the holders thereof who are entitled to
receive any dividend or other distribution, the Company shall notify the Holder
in writing of such record date at least twenty (20) days prior to the date
specified therein.

            2.5 Shares to be Fully Paid; Reservation of Shares. The Company
covenants and agrees that all shares of Common Stock which may be issued upon
the exercise of the rights represented by this Warrant will, upon payment of the
Exercise Price and issuance pursuant to Section 1.4 or a net issuance pursuant
to Section 1.5, be duly authorized, validly issued, fully paid and nonassessable
and free from all preemptive rights of any stockholder and free of all taxes,
liens and charges with respect to the issue thereof. The Company further
covenants and agrees that during the period within which the rights represented
by this Warrant may be exercised, the Company will at all times have authorized
and reserved, for the purpose of issue or transfer upon exercise of the
subscription rights evidenced by this Warrant, a sufficient number of shares of
authorized but unissued Common Stock, or other securities and property, when and
as required to provide for the exercise of the rights represented by this
Warrant. The Company will take all such action as may be necessary to assure
that such shares of Common Stock may be issued as provided herein without
violation of any applicable law or regulation, or of any requirements of any
domestic securities exchange upon which the Common Stock may be listed.

      3. Replacement of Warrants. On receipt by the Company of evidence
reasonably satisfactory to the Company of the loss, theft, destruction or
mutilation of this Warrant and, in the case of any such loss, theft or
destruction of this Warrant, on delivery of an indemnity agreement reasonably
satisfactory in form and amount to the Company or, in the case of any such
mutilation, on surrender and cancellation of such Warrant, the Company at its
expense shall execute and deliver to the Holder, in lieu thereof, a new Warrant
of like tenor.





                                       4
<PAGE>
      4. Investment Intent. Unless a current registration statement under the
Securities Act of 1933, as amended (the "Act"), shall be in effect with respect
to the securities to be issued upon exercise of this Warrant, the Holder, by
accepting this Warrant, covenants and agrees that, at the time of exercise
hereof, and at the time of any proposed transfer of any securities acquired upon
exercise hereof, the Holder shall deliver to the Company a written statement
that the securities acquired by the Holder upon exercise hereof are for the own
account of the Holder for investment and are not acquired with a view to, or for
sale in connection with, any distribution thereof (or any portion thereof) and
with no present intention (at any such time) of offering or distributing such
securities (or any portion thereof).

      5. No Rights or Liability as a Shareholder. This Warrant does not entitle
the Holder hereof to any voting rights or other rights as a shareholder of the
Company. No provisions hereof, in the absence of affirmative action by the
Holder to purchase Common Stock, and no enumeration herein of the rights or
privileges of the Holder, shall give rise to any liability of the Holder as a
shareholder of the Company.

      6. Representations of Holder. The Holder hereby represents and
acknowledges to the Company that:

            6.1 this Warrant, the Common Stock issuable upon exercise of this
Warrant and any securities issued with respect to any of them by way of a stock
dividend or stock split or in connection with a recapitalization, merger,
consolidation or other reorganization will be "restricted securities" as such
term is used in the rules and regulations under the Securities Act of 1933, as
amended (the "Securities Act"), and that such securities have not been and may
not be registered under the Securities Act or any state securities law, and that
such securities must be held indefinitely unless registration is effected or
transfer can be made pursuant to appropriate exemptions;

            6.2 the Holder has read, and fully understands, the terms of this
Warrant set forth on its face and the attachments hereto, including the
restrictions on transfer contained herein;

            6.3 the Holder is purchasing for investment for its own account and
not with a view to or for sale in connection with any distribution of this
Warrant or the Common Stock of the Company issuable upon exercise of this
Warrant and it has no intention of selling such securities in a public
distribution in violation of the federal securities laws or any applicable state
securities laws;

            6.4 the Company may affix the following legends (in addition to any
other legend(s), if any, required by applicable state corporate and/or
securities laws) to certificates for shares of Common Stock (or other
securities) issued upon exercise of this Warrant ("Warrant Shares"):

                  "THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE
                  SECURITIES ACT OF 1933, AS AMENDED. THEY MAY NOT BE SOLD,
                  OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF A
                  REGISTRATION STATEMENT IN EFFECT WITH RESPECT TO THE
                  SECURITIES UNDER SUCH ACT OR AN OPINION OF COUNSEL
                  SATISFACTORY TO THE COMPANY THAT SUCH




                                       5
<PAGE>
                  REGISTRATION IS NOT REQUIRED OR UNLESS SOLD PURSUANT TO RULE
                  144 OF SUCH ACT.

                  THE SHARES REPRESENTED BY THIS CERTIFICATE MAY BE SUBJECT TO A
                  LOCKUP PERIOD OF UP TO 180 DAYS FOLLOWING THE EFFECTIVE DATE
                  OF A REGISTRATION STATEMENT OF THE COMPANY FILED UNDER THE
                  SECURITIES ACT OF 1933, AS AMENDED, AS MAY BE SET FORTH IN AN
                  AGREEMENT BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE
                  SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL
                  OFFICE OF THE COMPANY. SUCH LOCKUP PERIOD, IF ANY, IS BINDING
                  ON TRANSFEREES OF THESE SHARES."

      7. "Market Stand-Off" Agreement. Holder and/or any transferee hereby
agrees that, during the period of duration specified by the Company and an
underwriter of Common Stock or other securities of the Company (such period
shall not exceed one hundred eighty (180) days), following the effective date of
a registration statement of the Company filed under the Securities Act, it shall
not, to the extent requested by the Company and such underwriter, directly or
indirectly sell, offer to sell, contract to sell (including, without limitation,
any short sale), grant any option to purchase or otherwise transfer or dispose
of (other than to donees who agree to be similarly bound) any securities of the
Company held by it at any time during such period except Common Stock included
in such registration; provided, however, that such agreement shall be applicable
only to the first such registration statement of the Company which covers Common
Stock (or other securities) to be sold on its behalf to the public in an
underwritten offering and provided further that each executive officer and
director of the Company shall agree to execute a similar agreement.

                  In order to enforce the foregoing covenant, the Company may
impose stop-transfer instructions with respect to the Common Stock of the Holder
(and the shares or securities of every other person subject to the foregoing
restriction) until the end of such period.

      8. Acknowledgment by Holder. Holder hereby acknowledges and agrees that
this Warrant is issued in connection with an Initial Closing or Additional
Closing as the case may be (as defined in the Series D Purchase Agreement (as
defined below)) of the sale and issuance by the Company of shares of its Series
D Preferred Stock pursuant to that certain Series D Preferred Stock Purchase
Agreement dated as of April 30, 2003 (the "Series D Purchase Agreement"). Holder
further acknowledges and agrees by the issuance of this Warrant, the Company has
satisfied in full any obligations it may have in connection with the Initial
Closing or Additional Closing as the case may be to issue warrants pursuant to
Section 6 of that certain Engagement Letter dated as of October 17, 2002, by and
between the Company and Holder ("Engagement Letter").

      9. Limitations on Disposition. The Holder of this Warrant, by acceptance
hereof, agrees to comply in all respects with the provisions of this Section 9.
Without in any way limiting the representations set forth above, the Holder of
this Warrant agrees not to make any disposition of this Warrant or any Warrant
Shares, unless and until the transferee has agreed in writing for the benefit of
the Company to be bound by this Section 9 and the other provisions of this
Warrant as if such transferee were the original Holder hereof, provided and to
the extent such provisions are then applicable, and



                                       6
<PAGE>
                  (a) There is then in effect a Registration Statement under the
Securities Act covering such proposed disposition and such disposition is made
in accordance with such Registration Statement; or

                  (b) (i) the Holder shall have notified the Company of the
proposed disposition and shall have furnished the Company with a detailed
statement of the circumstances surrounding the proposed disposition, and the
Company has given its prior written consent, and (ii) if reasonably requested by
the Company, the Holder shall have furnished the Company with an opinion of
counsel, reasonably satisfactory to the Company, that such disposition will not
require registration of the Warrant and/or the Warrant Shares under the
Securities Act. It is agreed that the Company will not require opinions of
counsel for transactions made pursuant to Rule 144 except in unusual
circumstances.

      10. Miscellaneous.

            10.1 Transfer of Warrant. In addition to the transfer restrictions
set forth in Section 9, this Warrant shall not be transferable or assignable in
any manner and no interest shall be pledged or otherwise encumbered by the
Holder without the express written consent of the Company.

            10.2 Titles and Subtitles. The titles and subtitles used in this
Warrant are for convenience only and are not to be considered in construing
or interpreting this Warrant.

            10.3 Notice. Notice or demand pursuant to this Warrant shall be
sufficiently given or made, if sent by first-class mail, postage prepaid,
addressed, if to the Holder of this Warrant, to the Holder at its last known
address as it shall appear in the records of the Company, and if to the Company,
at 10590 W. Ocean Air Drive, Suite 200, San Diego, California 92130, Attention:
Secretary. The Company may alter the address to which communications are to be
sent by giving notice of such change of address in conformity with the
provisions of this Section 10.3 for the giving of notice.

            10.4 Attorneys' Fees. If any action at law or in equity is necessary
to enforce or interpret the terms of this Warrant, the prevailing party shall be
entitled to reasonable attorneys' fees, costs and disbursements in addition to
any other relief to which such party may be entitled.

            10.5 Amendment. This Warrant may be modified, amended or terminated
by a writing signed by the Company and the Holder.

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

            10.7 Governing Law. This Warrant shall be governed by and construed
and enforced in accordance with the laws of the State of California, without
giving effect to its conflicts of laws principles.





                                       7
<PAGE>
            10.8 Counterparts. This Warrant may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

Date: April 30, 2003                 SANTARUS, INC.


                                     By:   /s/ GERALD T. PROEHL
                                         ---------------------------------------
                                     Name:  Gerald T. Proehl
                                     Its:  President and Chief Executive Officer

ACKNOWLEDGED AND AGREED:

ROCKPORT VENTURE SECURITIES, LLC.

By:   /s/ THOMAS R. BASSINGER
    --------------------------------
Name: Thomas R. Bassinger
Its: Managing Director, Chief Executive Officer




                                       8
<PAGE>
                                   SCHEDULE 1
                               SUBSCRIPTION NOTICE
               (To be signed only on exercise of Warrant for cash)



To:   Santarus, Inc.

      The undersigned, the holder of the Warrant attached hereto, hereby
irrevocably elects to exercise the purchase rights represented by such Warrant
for, and to purchase thereunder, ________* shares of Common Stock of Santarus,
Inc., and herewith makes payment of $________ therefor, and requests that the
certificates for such shares be issued in the name of, and delivered to
______________________, whose address is ___________________________.


                  --------------------------------------------------------------
                  (Signature must conform in all respects to name of the Holder
                  as specified on the face of the Warrant)

                  --------------------------------------------------------------
                  (Print Name)

                  --------------------------------------------------------------
                  (Address)



Dated:
      -----------------

--------

* Insert here the number of shares as to which the Warrant is being exercised.

                                  Schedule 1-1
<PAGE>
                                   SCHEDULE 2

                         NOTICE OF NET ISSUANCE EXERCISE

             (To be signed only on net issuance exercise of Warrant)



To: Santarus, Inc.:

      Pursuant to Section 1.5 of the Warrant, the undersigned, the holder of the
Warrant attached hereto, hereby irrevocably elects to exercise the net issuance
rights with respect to ______________ shares of such Warrant for that number of
shares of Common Stock of Santarus, Inc., determined pursuant to the formula set
forth in Section 1.5 of the Warrant, and requests that the certificates for such
shares be issued in the name of, and delivered to __________________, whose
address is ___________________________.

                  --------------------------------------------------------------
                  (Signature must conform in all respects to name of the Holder
                  as specified on the face of the Warrant)

                  --------------------------------------------------------------
                              (Print Name)

                  --------------------------------------------------------------
                              (Address)


Dated:
      -----------------



                                  Schedule 2-1