Document:

<Page>

                                                                     Exhibit 4.6

                         FORM OF 0% SERIES B GLOBAL NOTE

                             [FACE OF SERIES B NOTE]

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY OR ITS
AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE
ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO
CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

THIS SECURITY AND THE SHARES OF SEPRACOR INC. (THE "COMPANY") COMMON STOCK
("COMMON STOCK") ISSUABLE UPON CONVERSION OF THIS SECURITY HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"),
OR ANY STATE SECURITIES LAWS. NEITHER THIS SECURITY, THE SHARES OF COMMON STOCK
ISSUABLE UPON CONVERSION OF THIS SECURITY NOR ANY INTEREST OR PARTICIPATION
HEREIN OR THEREIN MAY BE REOFFERED, SOLD, ASSIGNED, TRANSFERRED, PLEDGED,
ENCUMBERED OR OTHERWISE DISPOSED OF IN THE ABSENCE OF SUCH REGISTRATION OR
UNLESS SUCH TRANSACTION IS EXEMPT FROM, OR NOT SUBJECT TO, REGISTRATION.

THE HOLDER OF THIS SECURITY, BY ITS ACCEPTANCE HEREOF, AGREES TO OFFER, SELL OR
OTHERWISE TRANSFER SUCH SECURITY, PRIOR TO THE DATE (THE "RESALE RESTRICTION
TERMINATION DATE") THAT IS TWO YEARS AFTER THE LATER OF THE ORIGINAL ISSUE DATE
HEREOF AND THE LAST DATE ON WHICH THE COMPANY OR ANY AFFILIATE OF THE COMPANY
WAS THE OWNER OF THIS SECURITY (OR ANY PREDECESSOR OF SUCH SECURITY) ONLY (A) TO
THE COMPANY OR ANY SUBSIDIARY THEREOF, (B) FOR SO LONG AS THE SECURITIES ARE
ELIGIBLE FOR RESALE PURSUANT TO RULE 144A, TO A PERSON IT REASONABLY BELIEVES IS
A "QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN RULE 144A UNDER THE SECURITIES
ACT THAT PURCHASES FOR ITS OWN ACCOUNT OR FOR THE ACCOUNT OF A QUALIFIED
INSTITUTIONAL BUYER TO WHICH NOTICE IS GIVEN THAT THE TRANSFER IS BEING MADE IN
RELIANCE ON RULE 144A, (C) PURSUANT TO A REGISTRATION STATEMENT THAT HAS BEEN
DECLARED EFFECTIVE UNDER THE SECURITIES ACT, OR (D) PURSUANT TO ANOTHER
AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT,
SUBJECT TO THE RIGHTS OF THE COMPANY AND THE TRUSTEE PRIOR TO ANY SUCH OFFER,
SALE OR TRANSFER PURSUANT TO CLAUSE (D) TO REQUIRE THE DELIVERY OF AN OPINION OF
COUNSEL, CERTIFICATION AND/OR OTHER INFORMATION SATISFACTORY TO EACH OF THEM,
AND IN EACH OF THE FOREGOING CASES WHERE REGISTRATION OR

                                        1
<Page>

TRANSFER OF THIS SECURITY IS REQUIRED, A CERTIFICATE OF TRANSFER IN THE FORM
APPEARING ON THE OTHER SIDE OF THIS SECURITY COMPLETED AND DELIVERED BY THE
TRANSFEROR TO THE TRUSTEE. THIS LEGEND WILL BE REMOVED AFTER THE RESALE
RESTRICTION TERMINATION DATE UPON THE REQUEST OF THE HOLDER AND THE DELIVERY OF
AN OPINION OF COUNSEL, CERTIFICATES AND/OR OTHER INFORMATION SATISFACTORY TO THE
COMPANY.

                                        2
<Page>

                                  SEPRACOR INC.

                                     Form of
           0% Series B Convertible Senior Subordinated Notes due 2010

No.                                                                   $[_______]

CUSIP No. 817315AS3

       Sepracor Inc., a corporation duly organized and validly existing under
the laws of the State of Delaware (herein called the "Company", which term
includes any successor corporation under the Indenture referred to on the
reverse hereof), for value received hereby promises to pay to CEDE & CO., or
registered assigns, the principal sum of _________ Dollars (which amount may
from time to time be increased or decreased to such other principal amounts
(which, taken together with the principal amounts of all other outstanding
Notes, shall not exceed $_______ in aggregate at any time (or $_________ if the
option set forth in the Purchase Agreement is exercised in full by the Initial
Purchasers)) by adjustments made on the records of the Trustee, as Custodian of
the Depositary, in accordance with the rules and procedures of the Depositary)
on December 15, 2010, and Liquidated Damages in the manner, at the rates and to
the persons set forth in the Registration Rights Agreement.

       Payment of the principal of and Liquidated Damages accrued on this Note
shall be made at the office or agency of the Company maintained for that purpose
in the Borough of Manhattan, The City of New York, or, at the option of the
holder of this Note, at the Corporate Trust Office, in such lawful money of the
United States of America as at the time of payment shall be legal tender for the
payment of public and private debts; PROVIDED, HOWEVER, Liquidated Damages may
be paid by check mailed to your address as it appears in the Note register;
PROVIDED FURTHER, HOWEVER, that, with respect to any holder of Notes with an
aggregate principal amount equal to or in excess of $2,000,000, at the request
of such holder in writing to the Company, Liquidated Damages on such holder's
Notes shall be paid by wire transfer in immediately available funds in
accordance with the written wire transfer instruction supplied by such holder
from time to time to the Trustee and paying agent (if different from the
Trustee) at least two days prior to the applicable record date; provided that
any payment to the Depositary or its nominee shall be paid by wire transfer in
immediately available funds in accordance with the wire transfer instruction
supplied by the Depositary or its nominee from time to time to the Trustee and
paying agent (if different from Trustee) at least two days prior to the
applicable record date.

       Reference is made to the further provisions of this Note set forth on the
reverse hereof, including, without limitation, provisions subordinating the
payment of principal of and premium, if any, and Liquidated Damages on this Note
to the prior payment in full of all Senior Obligations as defined in the
Indenture and provisions giving the holder of this Note the right to convert
this Note into Common Stock of the Company on the terms and subject to the
limitations referred to on the reverse hereof and as more fully specified in the
Indenture. Such further provisions shall for all purposes have the same effect
as though fully set forth at this place.

                                        3
<Page>

       This Note shall be deemed to be a contract made under the laws of the
State of New York, and for all purposes shall be construed in accordance with
and governed by the laws of said State (without regard to the conflicts of laws
provisions thereof).

       This Note shall not be valid or become obligatory for any purpose until
the certificate of authentication hereon shall have been manually signed by the
Trustee or a duly authorized authenticating agent under the Indenture.

                  [Remainder of page intentionally left blank]

                                        4
<Page>

IN WITNESS WHEREOF, the Company has caused this Note to be duly executed.

                                               SEPRACOR INC.

                                               By:
                                                  ------------------------------
                                                     Name:
                                                     Title:

Attest:

-----------------------------
Name:
Title:

Dated: December 12, 2003

TRUSTEE'S CERTIFICATE OF AUTHENTICATION

JPMORGAN CHASE BANK,
as Trustee, certifies that this is one of the Notes described
in the within-named Indenture.

By:
   --------------------------
      Authorized Signatory

                                        5
<Page>

                           [REVERSE OF SERIES B NOTE]

                                  SEPRACOR INC.

           0% Series B Convertible Senior Subordinated Notes due 2010

       This Note is one of a duly authorized issue of Notes of the Company,
designated as its 0% Series B Convertible Senior Subordinated Notes due 2010
(herein called the "Notes"), limited to the aggregate principal amount of
$___________ (or $___________ if the option set forth in the Purchase Agreement
is exercised in full by the Initial Purchasers) all issued or to be issued under
and pursuant to an Indenture dated as of December 12, 2003 (herein called the
"Indenture"), between the Company and JPMorgan Chase Bank, (herein called the
"Trustee"), to which Indenture and all indentures supplemental thereto reference
is hereby made for a description of the rights, limitations of rights,
obligations, duties and immunities thereunder of the Trustee, the Company and
the holders of the Notes. Additional Notes may be issued in an unlimited
aggregate principal amount, subject to certain conditions specified in the
Indenture.

       In case an Event of Default, as defined in the Indenture, shall have
occurred and be continuing, the principal of, premium, if any, and accrued
Liquidated Damages, if any, on all Notes may be declared, and upon said
declaration shall become, due and payable, in the manner, with the effect and
subject to the conditions provided in the Indenture.

       The Indenture contains provisions permitting the Company and the Trustee
in certain circumstances, without the consent of the holders of the Notes, and
in other circumstances, with the consent of the holders of not less than a
majority in aggregate principal amount of the Notes at the time outstanding,
evidenced as in the Indenture provided, to execute supplemental indentures
adding any provisions to or changing in any manner or eliminating any of the
provisions of the Indenture or of any supplemental indenture or modifying in any
manner the rights of the holders of the Notes; PROVIDED, HOWEVER, that no such
supplemental indenture shall (i) extend the fixed maturity of any Note, or
reduce the rate or extend the time of payment of Liquidated Damages thereon, or
reduce the principal amount thereof or premium, if any, thereon, or reduce any
amount payable on repurchase thereof, impair, or change in any respect adverse
to the holder of Notes, the obligation of the Company to repurchase any Note at
the option of the holder upon the happening of a Designated Event, or impair or
adversely affect the right of any Noteholder to institute suit for the payment
thereof, or change the currency in which the Notes are payable, or impair or
change in any respect adverse to the Noteholders the right to convert the Notes
into Common Stock or any other property receivable upon conversion subject to
the terms set forth in the Indenture, or modify the provisions of the Indenture
with respect to the subordination of the Notes in a manner adverse to the
Noteholders, reduce the quorum or voting requirements under the Indenture with
respect to the Notes, subject to certain exceptions, modify certain provisions
of the Indenture relating to these modification provisions, in each case without
the consent of the holder of each Note so affected, or (ii) reduce the aforesaid
percentage of Notes, the holders of which are required to consent to any such
supplemental indenture, without the consent of the holders of all Notes then
outstanding. It is also provided in the Indenture that, prior to any declaration
accelerating the maturity of the Notes, the holders of a majority in

                                        6
<Page>

aggregate principal amount of the Notes at the time outstanding may on behalf of
the holders of all of the Notes waive any past default or Event of Default under
the Indenture and its consequences except (i) a default in the payment of
Liquidated Damages or premium, if any, on, or the principal of, the Notes when
due which default has not been cured, (ii) a failure by the Company to convert
any Notes into Common Stock or (iii) a default in respect of a covenant or
provisions of the Indenture which under Article XI of the Indenture cannot be
modified or amended without the consent of the holders of all Notes then
outstanding. Any such consent or waiver by the holder of this Note (unless
revoked as provided in the Indenture) shall be conclusive and binding upon such
holder and upon all future holders and owners of this Note and any Notes which
may be issued in exchange or substitution hereof, irrespective of whether or not
any notation thereof is made upon this Note or such other Notes.

       The indebtedness evidenced by the Notes is, to the extent and in the
manner provided in the Indenture, expressly subordinate and subject in right of
payment to the prior payment in full in cash or other payment satisfactory to
the holders of Senior Obligations of all Senior Obligations of the Company, as
defined in the Indenture, whether outstanding at the date of the Indenture or
thereafter incurred, and this Note is issued subject to the provisions of the
Indenture with respect to such subordination. Each holder of this Note, by
accepting the same, agrees to and shall be bound by such provisions and
authorizes the Trustee on his behalf to take such action as may be necessary or
appropriate to effectuate the subordination so provided and appoints the Trustee
his attorney in fact for such purpose.

       No reference herein to the Indenture and no provision of this Note or of
the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of, premium, if any, and
Liquidated Damages on this Note at the place, at the respective times, at the
rate and in the lawful money herein prescribed.

       The Notes are issuable in registered form without coupons in
denominations of $1,000 principal amount and integral multiples thereof. At the
office or agency of the Company referred to on the face hereof, and in the
manner and subject to the limitations provided in the Indenture, without payment
of any service charge but with payment of a sum sufficient to cover any tax or
other governmental charge that may be imposed in connection with any
registration or exchange of Notes, Notes may be exchanged for a like aggregate
principal amount of Notes of other authorized denominations.

       The Notes will not be redeemable by the Company.

       The Notes are not subject to redemption through the operation of any
sinking fund.

       Upon the occurrence of a "Designated Event," the Noteholder has the
right, at such holder's option, to require the Company to repurchase all of such
holder's Notes or any portion thereof (in principal amounts of $1,000 or
integral multiples thereof) on the Designated Event Purchase Date at a price
equal to 100% of the principal amount of the Notes such holder elects to require
the Company to repurchase, together with accrued and unpaid Liquidated Damages,
if any, to but excluding the date fixed for repurchase. The Company or, at the
written request of the Company, the Trustee shall mail to all holders of record
of the Notes a notice of the

                                        7
<Page>

occurrence of a Designated Event and of the repurchase right arising as a result
thereof on or before the tenth calendar day after the occurrence of such
Designated Event.

       Subject to the provisions of the Indenture, the holder hereof has the
right, at its option, at any time following the date of original issuance of the
Notes and prior to the close of business on December 15, 2010, to convert the
principal hereof or any portion of such principal which is $1,000 or an integral
multiple thereof, into that number of fully paid and non-assessable shares of
Company's Common Stock, as said shares shall be constituted at the date of
conversion, at the Conversion Rate, as adjusted from time to time as provided in
the Indenture, for each $1,000 principal amount of Notes so converted, upon
surrender of this Note, together with a conversion notice as provided in the
Indenture and this Note, to the Company at the office or agency of the Company
maintained for that purpose in the Borough of Manhattan, The City of New York,
or at the option of such holder, the Corporate Trust Office, and, unless the
shares issuable on conversion are to be issued in the same name as this Note,
duly endorsed by, or accompanied by instruments of transfer in form satisfactory
to the Company duly executed by, the holder or by his duly authorized attorney.
The initial Conversion Rate shall be 33.5175 shares for each $1,000 principal
amount of Notes. No fractional shares of Common Stock will be issued upon any
conversion, but an adjustment in cash will be paid to the holder, as provided in
the Indenture, in respect of any fraction of a share which would otherwise be
issuable upon the surrender of any Note or Notes for conversion. No adjustment
shall be made for dividends or any shares issued upon conversion of such Note
except as provided in Section 15.5 of the Indenture.

       Upon due presentment for registration of transfer of this Note at the
office or agency of the Company in the Borough of Manhattan, The City of New
York, a new Note or Notes of authorized denominations for an equal aggregate
principal amount will be issued to the transferee in exchange thereof, subject
to the limitations provided in the Indenture, without charge except for any tax,
assessments or other governmental charge imposed in connection therewith.

       The Company, the Trustee, any authenticating agent, any paying agent, any
conversion agent and any Note registrar may deem and treat the registered holder
hereof as the absolute owner of this Note (whether or not this Note shall be
overdue and notwithstanding any notation of ownership or other writing hereon),
for the purpose of receiving payment hereof, or on account hereof, for the
conversion hereof and for all other purposes, and neither the Company nor the
Trustee nor any other authenticating agent nor any paying agent nor any other
conversion agent nor any Note registrar shall be affected by any notice to the
contrary. Notwithstanding the foregoing, the Indenture provides that owners of
beneficial interests in a Global Note may directly enforce against the Company
such owners' right to exchange such beneficial interest for Notes in
certificated form. All payments made to or upon the order of such registered
holder shall, to the extent of the sum or sums paid, satisfy and discharge
liability for monies payable on this Note.

       No recourse for the payment of the principal of or any premium or
Liquidated Damages on this Note, or for any claim based hereon or otherwise in
respect hereof, and no recourse under or upon any obligation, covenant or
agreement of the Company in the Indenture or any indenture supplemental thereto
or in any Note, or because of the creation of any indebtedness represented
thereby, shall be had against any incorporator, stockholder, employee, agent,
officer, director or

                                        8
<Page>

subsidiary, as such, past, present or future, of the Company or of any successor
corporation, either directly or through the Company or any successor
corporation, whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

       Terms used in this Note and defined in the Indenture are used herein as
therein defined.

                                        9
<Page>

                                  ABBREVIATIONS

The following abbreviations, when used in the inscription of the face of this
Note, shall be construed as though they were written out in full according to
applicable laws or regulations:

TEN COM - as tenants in common              UNIF GIFT MIN ACT -

                                            ___________________________Custodian
                                                       (Cust)

TEN ENT - as tenants by the entireties      __________________________________
                                                      (Minor)

JT TEN  - as joint tenants with right of
survivorship and not as tenants in common   Uniform Gifts to Minors Act_________
                                                                        (State)

                    Additional abbreviations may also be used
                          though not in the above list.

                                       10
<Page>

                           [FORM OF CONVERSION NOTICE]

To: Sepracor Inc.

       The undersigned registered owner of this Note hereby irrevocably
exercises the option to convert this Note, or the portion hereof (which is
$1,000 principal amount or an integral multiple thereof) below designated, into
shares of Common Stock in accordance with the terms of the Indenture referred to
in this Note, and directs that the shares issuable and deliverable upon such
conversion, together with any check in payment for fractional shares and any
Notes representing any unconverted principal amount hereof, be issued and
delivered to the registered holder hereof unless a different name has been
indicated below. If shares or any portion of this Note not converted are to be
issued in the name of a person other than the undersigned, the undersigned will
pay all transfer taxes payable with respect thereto. Any amount required to be
paid to the undersigned on account of interest accompanies this Note.

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

                                                --------------------------------

                                                --------------------------------
                                                Signature(s)

--------------------------------
Signature Guarantee

Signature(s) must be guaranteed
by an eligible Guarantor
Institution (banks, stock
brokers, savings and loan
associations and credit unions)
with membership in an approved
signature guarantee medallion
program pursuant to Securities
and Exchange Commission
Rule 17Ad-15 if shares of
Common Stock are to be issued,
or Notes to be delivered, other
than to and in the name of the
registered holder.

                                       11
<Page>

Fill in for registration of
shares if to be issued, and
Notes if to be delivered,
other than to and in the name
of the registered holder:

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

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

-----------------------------
(City, State and Zip Code)

Please print name and address

                                               Principal amount to be
                                               converted (if less than all):
                                               $______,000

                                               _________________________________
                                               Social Security or Other Taxpayer
                                               Identification Number

                                       12
<Page>

                       [FORM OF OPTION TO ELECT REPAYMENT

                            UPON A DESIGNATED EVENT]

To: Sepracor Inc.

       The undersigned registered owner of this Note hereby acknowledges receipt
of a notice from Sepracor Inc. (the "Company") as to the occurrence of a
Designated Event with respect to the Company and requests and instructs the
Company to repay the entire principal amount of this Note, or the portion
thereof (which is $1,000 principal amount or an integral multiple thereof) below
designated, in accordance with the terms of the Indenture referred to in this
Note, together with accrued Liquidated Damages to, but excluding, such date, to
the registered holder hereof.

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

                                               ---------------------------------

                                               ---------------------------------
                                               Signature(s)

                                               _________________________________
                                               Social Security or Other Taxpayer
                                               Identification Number

                                               Principal amount to be repaid
                                               (if less than all): $______,000

                                               NOTICE: The above signatures of
                                               the holder(s) hereof must
                                               correspond with the name as
                                               written upon the face of the
                                               Note in every particular without
                                               alteration or enlargement or any
                                               change whatever.

                                       13
<Page>

                        [FORM OF ASSIGNMENT AND TRANSFER]

       For value received ____________________________ hereby sell(s), assign(s)
and transfer(s) unto _________________ (Please insert social security or
Taxpayer Identification Number of assignee) the within Note, and hereby
irrevocably constitutes and appoints _____________________ attorney to transfer
the said Note on the books of the Company, with full power of substitution in
the premises.

       In connection with any transfer of the within Note occurring within two
years (or such other holding period required under Rule 144(k) of the Securities
Act) of the original issuance of such Note (unless such Note is being
transferred pursuant to a registration statement that has been declared
effective under the Securities Act), the undersigned confirms that such Note is
being transferred:

       / /    *To Sepracor Inc. or a subsidiary thereof; or

       / /    *Pursuant to and in compliance with Rule 144A under the Securities
              Act of 1933, as amended; or

       / /    *Pursuant to and in compliance with Rule 144 under the Securities
              Act of 1933, as amended;

       and unless the box below is checked, the undersigned confirms that such
Note is not being transferred to an "affiliate" of the Company as defined in
Rule 144 under the Securities Act of 1933, as amended (an "Affiliate"):

       / /    *The transferee is an Affiliate of the Company.

                                       14
<Page>

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

--------------------------------

--------------------------------
Signature(s)

--------------------------------
Signature Guarantee

       Signature(s) must be
guaranteed by an eligible
Guarantor Institution (banks,
stock brokers, savings and
loan associations and credit
unions) with membership in an
approved signature guarantee
medallion program pursuant to
Securities and Exchange
Commission Rule 17Ad-15 if
shares of Common Stock are to
be issued, or Notes to be
delivered, other than to and
in the name of the registered
holder.

       NOTICE: The signature on the conversion notice, the option to elect
repurchase upon a Designated Event or the assignment must correspond with the
name as written upon the face of the Note in every particular without alteration
or enlargement or any change whatever.

                                       15<Page>

                                                                    Exhibit 10.5

                                  SEPRACOR INC.

                        1998 EMPLOYEE STOCK PURCHASE PLAN

       The purpose of this Plan is to provide eligible employees of Sepracor
Inc. (the "Company") and certain of its subsidiaries with opportunities to
purchase shares of the Company's common stock, $.10 par value (the "Common
Stock"), commencing on June 1, 1998. Three hundred thousand (300,000) shares of
Common Stock in the aggregate have been approved for this purpose.

       1. ADMINISTRATION. The Plan will be administered by the Company's Board
of Directors (the "Board") or by a Committee appointed by the Board (the
"Committee"). The Board or the Committee has authority to make rules and
regulations for the administration of the Plan and its interpretation and
decisions with regard thereto shall be final and conclusive.

       2. ELIGIBILITY. Participation in the Plan will neither be permitted nor
denied contrary to the requirements of Section 423 of the Internal Revenue Code
of 1986, as amended (the "Code"), and regulations promulgated thereunder. All
employees of the Company, including Directors who are employees, and all
employees of any subsidiary of the Company (as defined in Section 424(f) of the
Code) designated by the Board or the Committee from time to time (a "Designated
Subsidiary"), are eligible to participate in any one or more of the offerings of
Options (as defined in Section 9) to purchase Common Stock under the Plan
provided that:

               a) they are customarily employed by the Company or a Designated
Subsidiary for more than 20 hours a week and for more than five months in a
calendar year; and

               b) they are employees of the Company or a Designated Subsidiary
on the first day of the applicable Plan Period (as defined below).

       No employee may be granted an option hereunder if such employee,
immediately after the option is granted, owns 5% or more of the total combined
voting power or value of the stock of the Company or any subsidiary. For
purposes of the preceding sentence, the attribution rules of Section 424(d) of
the Code shall apply in determining the stock ownership of an employee, and all
stock which the employee has a contractual right to purchase shall be treated as
stock owned by the employee.

       3. OFFERINGS. The Company will make one or more offerings ("Offerings")
to employees to purchase stock under this Plan. Offerings will begin each June 1
and December 1, or the first business day thereafter (the "Offering Commencement
Dates"). Each Offering Commencement Date will begin a six-month period (a "Plan
Period") during which payroll deductions will be made and held for the purchase
of Common Stock at the end of the Plan Period. The Board or the

<Page>

Committee may, at its discretion, choose a different Plan Period of twelve (12)
months or less for subsequent Offerings.

       4. PARTICIPATION. An employee eligible on the Offering Commencement Date
of any Offering may participate in such Offering by completing and forwarding a
payroll deduction authorization form to the employee's appropriate payroll
office at least 30 days prior to the applicable Offering Commencement Date. The
form will authorize a regular payroll deduction from the Compensation received
by the employee during the Plan Period. Unless an employee files a new form or
withdraws from the Plan, his deductions and purchases will continue at the same
rate for future Offerings under the Plan as long as the Plan remains in effect.
The term "Compensation" means the amount of money reportable on the employee's
Federal Income Tax Withholding Statement, excluding overtime, incentive or bonus
awards, allowances and reimbursements for expenses such as relocation allowances
for travel expenses, income or gains on the exercise of Company stock options,
and similar items, whether or not shown on the employee's Federal Income Tax
Withholding Statement.

       5. DEDUCTIONS. The Company will maintain payroll deduction accounts for
all participating employees. Payroll deductions may be at the rate of 1%, 2%,
3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% of Compensation with any change in
compensation during the Plan Period to result in an automatic corresponding
change in the dollar amount withheld.

       No employee may be granted an Option (as defined in Section 9) which
permits his rights to purchase Common Stock under this Plan and any other
employee stock purchase plan (as defined in Section 423(b) of the Code) of the
Company and its subsidiaries, to accrue at a rate which exceeds $25,000 of the
fair market value of such Common Stock (determined at the Offering Commencement
Date of the Plan Period) for each calendar year in which the Option is
outstanding at any time.

       6. DEDUCTION CHANGES. An employee may decrease or discontinue his payroll
deduction once during any Plan Period, by filing a new payroll deduction
authorization form. However, an employee may not increase his payroll deduction
during a Plan Period. If an employee elects to discontinue his payroll
deductions during a Plan Period, but does not elect to withdraw his funds
pursuant to Section 8 hereof, funds deducted prior to his election to
discontinue will be applied to the purchase of Common Stock on the Exercise Date
(as defined below).

       7. INTEREST. Interest will not be paid on any employee accounts, except
to the extent that the Board or the Committee, in its sole discretion, elects to
credit employee accounts with interest at such per annum rate as it may from
time to time determine.

       8. WITHDRAWAL OF FUNDS. An employee may at any time prior to the close of
business on the last business day in a Plan Period and for any reason
permanently draw out the balance

<Page>

accumulated in the employee's account and thereby withdraw from participation in
an Offering. Partial withdrawals are not permitted. The employee may not begin
participation again during the remainder of the Plan Period. The employee may
participate in any subsequent Offering in accordance with terms and conditions
established by the Board or the Committee.

       9. PURCHASE OF SHARES. On the Offering Commencement Date of each Plan
Period, the Company will grant to each eligible employee who is then a
participant in the Plan an option ("Option") to purchase on the last business
day of such Plan Period (the "Exercise Date"), at the Option Price hereinafter
provided for, the largest number of whole shares of Common Stock of the Company
as does not exceed the number of shares determined by dividing the Plan Period
Limit by the closing price (as defined below) on the Offering Commencement Date
of such Plan Period. The Plan Period Limit shall be equal to $208.33 multiplied
by the number of whole months in the Plan Period, rounded to the nearest whole
dollar.

       The purchase price for each share purchased will be 85% of the closing
price of the Common Stock on (i) the first business day of such Plan Period or
(ii) the Exercise Date, whichever closing price shall be less. Such closing
price shall be (a) the closing price on any national securities exchange on
which the Common Stock is listed, (b) the closing price of the Common Stock on
the Nasdaq National Market or (c) the average of the closing bid and asked
prices in the over-the-counter-market, whichever is applicable, as published in
The Wall Street Journal. If no sales of Common Stock were made on such a day,
the price of the Common Stock for purposes of clauses (a) and (b) above shall be
the reported price for the next preceding day on which sales were made.

       Each employee who continues to be a participant in the Plan on the
Exercise Date shall be deemed to have exercised his Option at the Option Price
on such date and shall be deemed to have purchased from the Company the number
of full shares of Common Stock reserved for the purpose of the Plan that his
accumulated payroll deductions on such date will pay for, but not in excess of
the maximum number determined in the manner set forth above.

       Any balance remaining in an employee's payroll deduction account at the
end of a Plan Period will be automatically refunded to the employee, except that
any balance which is less than the purchase price of one share of Common Stock
will be carried forward into the employee's payroll deduction account for the
following Offering, unless the employee elects not to participate in the
following Offering under the Plan, in which case the balance in the employee's
account shall be refunded.

       10. ISSUANCE OF CERTIFICATES. Certificates representing shares of Common
Stock purchased under the Plan may be issued only in the name of the employee,
in the name of the employee and another person of legal age as joint tenants
with rights of survivorship, or (in the Company's sole discretion) in the name
of a brokerage firm, bank or other nominee holder designated by the employee.
The Company may, in its sole discretion and in compliance with applicable laws,
authorize the use of book entry registration of shares in lieu of issuing stock
certificates.

<Page>

       11. RIGHTS ON RETIREMENT, DEATH OR TERMINATION OF EMPLOYMENT. In the
event of a participating employee's termination of employment prior to the last
business day of a Plan Period, no payroll deduction shall be taken from any pay
due and owing to an employee and the balance in the employee's account shall be
paid to the employee or, in the event of the employee's death, (a) to a
beneficiary previously designated in a revocable notice signed by the employee
(with any spousal consent required under state law) or (b) in the absence of
such a designated beneficiary, to the executor or administrator of the
employee's estate or (c) if no such executor or administrator has been appointed
to the knowledge of the Company, to such other person(s) as the Company may, in
its discretion, designate. If, prior to the last business day of the Plan
Period, the Designated Subsidiary by which an employee is employed shall cease
to be a subsidiary of the Company, or if the employee is transferred to a
subsidiary of the Company that is not a Designated Subsidiary, the employee
shall be deemed to have terminated employment for the purposes of this Plan.

       12. OPTIONEES NOT STOCKHOLDERS. Neither the granting of an Option to an
employee nor the deductions from his pay shall constitute such employee a
stockholder of the shares of Common Stock covered by an Option under this Plan
until such shares have been purchased by and issued to him.

       13. RIGHTS NOT TRANSFERABLE. Rights under this Plan are not transferable
by a participating employee other than by will or the laws of descent and
distribution, and are exercisable during the employee's lifetime only by the
employee.

       14. APPLICATION OF FUNDS. All funds received or held by the Company under
this Plan may be combined with other corporate funds and may be used for any
corporate purpose.

       15. ADJUSTMENT IN CASE OF CHANGES AFFECTING COMMON STOCK. In the event of
a subdivision of outstanding shares of Common Stock, or the payment of a
dividend in Common Stock, the number of shares approved for this Plan, and the
share limitation set forth in Section 9, shall be increased proportionately, and
such other adjustment shall be made as may be deemed equitable by the Board or
the Committee. In the event of any other change affecting the Common Stock, such
adjustment shall be made as may be deemed equitable by the Board or the
Committee to give proper effect to such event.

       16. MERGER. If the Company shall at any time merge or consolidate with
another corporation and the holders of the capital stock of the Company
immediately prior to such merger or consolidation continue to hold at least 80%
by voting power of the capital stock of the surviving corporation ("Continuity
of Control"), the holder of each Option then outstanding will thereafter be
entitled to receive at the next Exercise Date upon the exercise of such Option
for each share as to which such Option shall be exercised the securities or
property which a holder of one share of the Common Stock was entitled to upon
and at the time of such merger or consolidation, and the Board or the Committee
shall take such steps in connection with such merger or consolidation as the
Board or the Committee shall deem necessary to assure that the

<Page>

provisions of Section 15 shall thereafter be applicable, as nearly as reasonably
may be, in relation to the said securities or property as to which such holder
of such Option might thereafter be entitled to receive thereunder.

       In the event of a merger or consolidation of the Company with or into
another corporation which does not involve Continuity of Control, or of a sale
of all or substantially all of the assets of the Company while unexercised
Options remain outstanding under the Plan, (a) subject to the provisions of
clauses (b) and (c), after the effective date of such transaction, each holder
of an outstanding Option shall be entitled, upon exercise of such Option, to
receive in lieu of shares of Common Stock, shares of such stock or other
securities as the holders of shares of Common Stock received pursuant to the
terms of such transaction; or (b) all outstanding Options may be cancelled by
the Board or the Committee as of a date prior to the effective date of any such
transaction and all payroll deductions shall be paid out to the participating
employees; or (c) all outstanding Options may be cancelled by the Board or the
Committee as of the effective date of any such transaction, provided that notice
of such cancellation shall be given to each holder of an Option, and each holder
of an Option shall have the right to exercise such Option in full based on
payroll deductions then credited to his account as of a date determined by the
Board or the Committee, which date shall not be less than ten (10) days
preceding the effective date of such transaction.

       17. AMENDMENT OF THE PLAN. The Board may at any time, and from time to
time, amend this Plan in any respect, except that (a) if the approval of any
such amendment by the shareholders of the Company is required by Section 423 of
the Code, such amendment shall not be effected without such approval, and (b) in
no event may any amendment be made which would cause the Plan to fail to comply
with Section 423 of the Code.

       18. INSUFFICIENT SHARES. In the event that the total number of shares of
Common Stock specified in elections to be purchased under any Offering plus the
number of shares purchased under previous Offerings under this Plan exceeds the
maximum number of shares issuable under this Plan, the Board or the Committee
will allot the shares then available on a pro rata basis.

       19. TERMINATION OF THE PLAN. This Plan may be terminated at any time by
the Board. Upon termination of this Plan all amounts in the accounts of
participating employees shall be promptly refunded.

       20. GOVERNMENTAL REGULATIONS. The Company's obligation to sell and
deliver Common Stock under this Plan is subject to listing on a national stock
exchange or quotation on the Nasdaq National Market and the approval of all
governmental authorities required in connection with the authorization, issuance
or sale of such stock.

       21. GOVERNING LAW. The Plan shall be governed by Delaware law except to
the extent that such law is preempted by federal law.

<Page>

       22. ISSUANCE OF SHARES. Shares may be issued upon exercise of an Option
from authorized but unissued Common Stock, from shares held in the treasury of
the Company, or from any other proper source.

       23. NOTIFICATION UPON SALE OF SHARES. Each employee agrees, by entering
the Plan, to promptly give the Company notice of any disposition of shares
purchased under the Plan where such disposition occurs within two years after
the date of grant of the Option pursuant to which such shares were purchased.

       24. Effective Date and Approval of Shareholders. The Plan shall take
effect on __________________, 1998 subject to approval by the shareholders of
the Company as required by Section 423 of the Code, which approval must occur
within twelve months of the adoption of the Plan by the Board.

                          Adopted by the Board of Directors on February 26, 1998

                                    Approved by the stockholders on May 27, 1998

<Page>

                                  SEPRACOR INC.

              AMENDMENT NO. 1 TO 1998 EMPLOYEE STOCK PURCHASE PLAN

The 1998 Employee Stock Purchase Plan (the "Plan") be and hereby is amended by
deleting the second sentence of the first paragraph of the Plan in its entirety
and inserting in lieu thereof the following:

       "Nine hundred thousand (900,000) shares of Common Stock in the aggregate
       have been approved for this purpose."

                         Adopted by the Board of Directors on February 20, 2003.

                                    Approved by the stockholders on May 22, 2003

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00062-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00062-of-00352.parquet"}]]