EXHIBIT 10.33

                          SECURITIES PURCHASE AGREEMENT

            THIS SECURITIES  PURCHASE  AGREEMENT (this "Agreement") is made this
23 day of March, 1999 by and between Hemasure Inc., a Delaware  corporation (the
"Company"), and Sepracor Inc., a Delaware corporation (the "Investor").

            WHEREAS,  the Investor has agreed to purchase from the Company,  and
the  Company has agreed to sell to the  Investor,  shares of common  stock,  par
value  $0.01 per share  ("Common  Stock"),  of the  Company,  on such  terms and
conditions as are set forth herein;

            WHEREAS,  the Investor has also agreed to purchase from the Company,
and the Company has agreed to sell to the Investor, warrants to purchase 667,000
shares of Common Stock, on such terms and conditions as are set forth herein;

            NOW,   THEREFORE,   in  consideration  of  these  premises  and  the
representations,  warranties and covenants set forth herein,  and for other good
and  valuable  consideration,  the  receipt and  sufficiency  of which is hereby
acknowledged, the parties hereto hereby agree as follows:

1.         PURCHASE AND SALE OF SECURITIES

           a.        Issuance of Common Stock; Grant of Warrants.

                     i.        Subject to the terms and  conditions set forth in
                               this Agreement and in reliance upon the Company's
                               and the Investor's respective representations set
                               forth  below,  the  Company  hereby  sells to the
                               Investor,  and the Investor hereby  purchases and
                               acquires  from  the  Company,  at  the  aggregate
                               purchase   price  of  Two   Million  One  Dollars
                               ($2,000,001)   (the   "Purchase   Price"),    (i)
                               1,333,334  shares (the  "Shares") of Common Stock
                               and (ii)  warrants (the  "Warrants")  to purchase
                               667,000  additional  shares of Common  Stock (the
                               "Warrant  Shares") at an exercise  price of $1.50
                               per share, which Warrants shall be subject to the
                               terms and  conditions  of the  Warrant  Agreement
                               (the "Warrant  Agreement") executed and delivered
                               by the  Company and the  Investor  simultaneously
                               herewith.

                     ii.       To evidence the  purchase  and sale  described in
                               Section  1.1(a) above,  simultaneously  herewith,
                               the Company has  executed  and  delivered  to the
                               Investor,  and the Investor  hereby  acknowledges
                               receipt  of, a duly  executed  stock  certificate
                               evidencing the Shares and a duly executed warrant
                               certificate  evidencing  the Warrants,  each duly
                               registered  in  the  Investor's   name,   against
                               delivery  by the  Investor  to the Company of the
                               full Purchase

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                               Price by wire transfer of  immediately  available
                               funds  to  such   account  as  the   Company  has
                               designated.

                     iii.      Simultaneously  herewith,  the  Company  and  the
                               Investor have executed and delivered to the other
                               the  Registration  Rights  Agreement  in the form
                               attached hereto as Exhibit A.


2.         REPRESENTATIONS AND WARRANTIES OF THE COMPANY

           The Company represents and warrants to the Investor that:

           a.        Corporate Organization.

                     The  Company  is  a  corporation  duly  organized,  validly
existing  and in good  standing  under  the laws of the State of  Delaware.  The
Company has filed all necessary documents to qualify to do business as a foreign
corporation  in,  and the  Company  is in good  standing  under the laws of each
jurisdiction in which the conduct of the Company's business or the nature of the
property  owned  requires  such  qualification,  except  where the failure to so
qualify would not have a material  adverse  effect on the business,  properties,
prospects,  profits or condition (financial or otherwise) of the Company and its
subsidiaries taken as a whole (a "Material Adverse Effect"). The Company has all
requisite  corporate  power  and  authority  and  has all  necessary  approvals,
licenses,  permits and  authorization  to own its properties and to carry on its
business  as now  conducted,  except  where  the  failure  to have  such  power,
authority,  approvals,  licenses,  permits  and  authorization  would not have a
Material  Adverse  Effect.  The Company has all  requisite  corporate  power and
authority to execute and deliver this Agreement,  the Warrant  Agreement and the
Registration Rights Agreement (collectively, the "Transaction Documents") and to
perform its obligations hereunder and thereunder.

           b.        Capitalization.

                     On the date hereof,  the  authorized  capital  stock of the
Company  consists of 20,000,000  shares of Common Stock and 1,000,000  shares of
preferred stock, par value $ 0.01 per share ("Preferred Stock"), of the Company,
of which  9,087,737  shares of Common Stock and no shares of Preferred Stock are
issued and  outstanding.  Except as set forth on Schedule 2(b) attached  hereto,
there are no options, warrants, equity securities, calls, rights, commitments or
agreements  of any  character  to which the Company is a party or by which it is
bound  obligating the Company to issue,  deliver or sell, or cause to be issued,
delivered  or  sold,  additional  shares  of  capital  stock of the  Company  or
obligating the Company to grant, extend, accelerate the vesting of or enter into
any such option, warrant, equity security, call, right, commitment or agreement.
All the  outstanding  shares of capital  stock of the Company have been duly and
validly issued and are fully paid and  non-assessable.  Upon issuance,  sale and
delivery as contemplated by this

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Agreement,  the Shares and the Warrant Shares will be duly  authorized,  validly
issued,  fully  paid  and  non-assessable  shares  of the  Company,  free of all
preemptive rights.

           c.        Corporate Proceedings, Etc.

                     The Board of  Directors of the Company has  authorized  the
execution,  delivery and  performance by the Company of each of the  Transaction
Documents  to which  it is a party  and  each of the  transactions  contemplated
hereby and thereby.  No other  corporate  action is necessary to authorize  such
execution,   delivery  and  performance  by  the  Company  of  such  Transaction
Documents,   and,   upon  such   execution   and  delivery   (assuming  the  due
authorization,  execution  and  delivery  by each party  thereto  other than the
Company),  each of such  Transaction  Documents  shall  constitute the valid and
binding obligation of the Company, enforceable against the Company in accordance
with its terms,  except  that such  enforcement  may be  subject to  bankruptcy,
insolvency, reorganization, moratorium or other similar laws now or hereafter in
effect  relating to  creditors'  rights and general  principles  of equity.  The
Company has  authorized  the issuance  and delivery of the Shares in  accordance
with this  Agreement  and has  reserved  for  issuance  shares  of Common  Stock
initially issuable upon exercise of the Warrants.

           d.        Absence of Defaults, Conflicts, Etc.

                     The execution and delivery of the Transaction  Documents do
not, and the fulfillment of the terms hereof and thereof by the Company, and the
issuance  of the Shares and the Warrant  Shares will not,  result in a breach of
any of the terms, conditions or provisions of, or constitute a default under, or
permit  the  acceleration  of  rights  under or  termination  of,  any  material
indenture,  mortgage, deed of trust, credit agreement, note or other evidence of
indebtedness,  or  other  material  agreement  of  the  Company  or  any  of its
subsidiaries,  or the certificate of  incorporation or the bylaws of the Company
(as amended through the date hereof), or, to the Company's  knowledge,  any rule
or regulation of any court or federal, state or foreign regulatory board or body
or  administrative  agency  having  jurisdiction  over the Company or any of its
subsidiaries  or over their  respective  properties or  businesses.  No consent,
approval,  order or  authorization  of, or  registration,  declaration or filing
with,  any court,  administrative  agency or  commission  or other  governmental
authority  or  instrumentality  is required by or with respect to the Company in
connection with the execution and delivery of this Agreement or the consummation
of the transactions contemplated hereby.

           e.        SEC Filings; Financial Statements.

                     i.        The Company has filed and made  available  to the
                               Investor   all  forms,   reports  and   documents
                               required  to be  filed  by the  Company  with the
                               Securities and Exchange  Commission ("SEC") since
                               January   1,   1998   other   than   registration
                               statements   on  Form  S-8   (collectively,   the
                               "Company SEC  Reports").  The Company SEC Reports
                               (i) at the time filed,  complied in all  material
                               respects with the applicable  requirements of the
                               Securities Act of

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                               1933, as amended (the "Securities  Act"), and the
                               Exchange  Act,  as the case may be,  and (ii) did
                               not at the time they were filed (or if amended or
                               superseded  by a filing prior to the date of this
                               Agreement,  then  on the  date  of  such  filing)
                               contain any untrue  statement of a material  fact
                               or omit to state a material  fact  required to be
                               stated in such  Company SEC Reports or  necessary
                               in order to make the  statements  in such Company
                               SEC  Reports,  in the light of the  circumstances
                               under which they were made, not misleading.

                     ii.       Each of the financial statements  (including,  in
                               each case,  any related  notes)  contained in the
                               Company  SEC  Reports  complied as to form in all
                               material  respects with the applicable  published
                               rules  and  regulations  of the SEC with  respect
                               thereto,   was   prepared  in   accordance   with
                               generally accepted accounting  principles applied
                               on a  consistent  basis  throughout  the  periods
                               involved (except as may be indicated in the notes
                               to such  financial  statements or, in the case of
                               unaudited statements,  as permitted by Form 10- Q
                               of the SEC) and fairly  presented  the  financial
                               position  of the  Company as of the dates and the
                               results of its  operations and cash flows for the
                               periods  indicated,  except  that  the  unaudited
                               interim financial  statements were or are subject
                               to  normal  and  recurring  year-end  adjustments
                               which were not or are not expected to be material
                               in amount.

           f.        No Undisclosed Liabilities.

                     Except as disclosed in the Company SEC Reports  filed prior
to the date  hereof,  and except for normal or  recurring  liabilities  incurred
since September 30, 1998 in the ordinary course of business consistent with past
practices, the Company does not have any liabilities, either accrued, contingent
or otherwise (whether or not required to be reflected in financial statements in
accordance with generally accepted accounting principles), and whether due or to
become due, which individually or in the aggregate are reasonably likely to have
a Material Adverse Effect.

           g.        Agreements, Contracts and Commitments.

                     The  Company has not  breached,  or received in writing any
claim or notice  that it has  breached,  any of the terms or  conditions  of any
material  agreement,  contract or commitment  filed as an exhibit to the Company
SEC Reports ("Material  Contracts") in such a manner as,  individually or in the
aggregate,  are  reasonably  likely  to have a  Material  Adverse  Effect.  Each
Material Contract that has not expired by its terms is in full force and effect.

           h.        Litigation.

                     Except as described in the Company SEC Reports  filed prior
to the date hereof, there is no action, suit or proceeding,  claim,  arbitration
or investigation against the Company

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pending or as to which the Company has received any written notice of assertion,
which, individually or in the aggregate, is reasonably likely to have a Material
Adverse  Effect or a material  adverse  effect on the  ability of the Company to
consummate the transactions contemplated by this Agreement.

           i.        Rights Agreement.

                     The entering into of this Agreement and the consummation of
the transactions  contemplated hereby do not and will not result in the grant of
any rights to any person under any shareholder  rights plan to which the Company
is a party.

           j.        No Other Representations or Warranties.

                     Except for the  representations  and  warranties  expressly
contained in this  Agreement and the other  Transaction  Documents,  neither the
Company nor any other person or entity makes any  representation  or warranty to
the  Investor,  express or implied,  and the Company  hereby  disclaims any such
representation or warranty, whether by the Company or any of its agents, brokers
or representatives or any other person or entity,  notwithstanding  the delivery
or  disclosure  to the Investor or any of its  officers,  directors,  employees,
agents or representatives or any other person or entity of any document or other
information by the Company or any of its agents,  brokers or  representatives or
any other person or entity.


3.         REPRESENTATIONS AND WARRANTIES OF THE INVESTOR

                     The  Investor  represents  and  warrants  to the Company as
follows:

           a.        Investment Intent, Etc.

                     i.  The Investor is acquiring the Shares,  the Warrants and
                         the  Warrant  Shares   (collectively,   the  "Purchased
                         Securities") for its own account,  as an investment and
                         not with a view to the distribution thereof.

                    ii.  The  Investor  understands  that none of the  Purchased
                         Securities have  been registered  under the  Securities
                         Act of  1933, as  amended  (the  "Securities   Act") in
                         reliance  on an  exemption  therefrom for  transactions
                         not  involving  a public offering, and that none of the
                         Purchased Securities have been approved  or disapproved
                         by the United States Securities and Exchange Commission
                         or by any other federal or state agency.

                    iii. The  Investor  understands  that  none of the Purchased
                         Securities may be sold,  transferred or assigned unless
                         registered  by  the  Company pursuant to the Securities
                         Act and any applicable state securities laws, or unless

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                         an exemption therefrom is  available, and, accordingly,
                         it  may  not  be possible for the Investor to liquidate
                         its  investment  in  the  Purchased  Securities, and it
                         agrees  not to sell,  assign  or otherwise  transfer or
                         dispose  of any Purchased    Securities   unless   such
                         Purchased   Securities   have   been  so registered  or
                         an exemption from registration is available.

                     iv. The Investor is  an accredited  investor,  as that term
                         is defined in Regulation D under the Securities Act.

           b.        Knowledge and Experience; Access to Information.

                     The Investor has such knowledge and experience in financial
and business  matters that it is capable of  evaluating  the merits and risks of
its investment in the Company as  contemplated  by this Agreement and is able to
bear the economic risk of such investment for an indefinite  period of time. The
Investor has been furnished  access to such  information and documents as it has
requested and has been afforded an  opportunity  to ask questions of and receive
answers from  representatives of the Company concerning the terms and conditions
of this  Agreement  and the purchase of the  Purchased  Securities  contemplated
hereby.

                     3.3       Corporate Organization.

                     The  Investor  is a  corporation  duly  organized,  validly
existing and in good  standing  under the laws of the State of Delaware.  On the
date hereof, the Investor has provided or made available to the Company true and
complete  copies of the  charter  and the  bylaws of the  Investor,  as  amended
through the date hereof.

                     3.4       Corporate Proceedings, Etc.

                     The Investor has authorized the  execution,  delivery,  and
performance  of the  Transaction  Documents  and  each of the  transactions  and
agreements  contemplated  hereby and  thereby.  No other  action is necessary to
authorize  such  execution,  delivery  and  performance  by the  Investor of the
Transaction  Documents,  and,  upon such  execution  and  delivery,  each of the
Transaction  Documents shall constitute the valid and binding  obligation of the
Investor,  enforceable against the Investor in accordance with its terms, except
that such enforcement may be subject to bankruptcy, insolvency,  reorganization,
moratorium  or other  similar  laws  now or  hereafter  in  effect  relating  to
creditors' rights and general principles of equity.


4.         SECURITIES ACT; LEGENDS

                     Stock  certificates  representing the Shares shall bear the
following  legend  only if such  Shares are not then  registered  pursuant to an
effective registration statement under the Securities Act:

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                      The securities  represented by this  certificate  have not
                      been  registered  under  the  Securities  Act of 1933,  as
                      amended (the "Act"), and may not be offered or sold except
                      pursuant to (i) an effective  registration statement under
                      the Act, (ii) to the extent applicable, Rule 144 under the
                      Act (or any  similar  rule under such Act  relating to the
                      disposition  of  securities),   or  (iii)  an  opinion  of
                      counsel, if such opinion shall be reasonably  satisfactory
                      to  counsel  to  the  issuer,   that  an  exemption   from
                      registration under such Act is available.


5.         CONFIDENTIALITY

                     As to  so  much  of  the  information  and  other  material
furnished under or in connection with this Agreement  (whether furnished before,
on or after the date hereof) as constitutes or contains  confidential  business,
financial or other  information of the Company or any  subsidiary,  the Investor
covenants for itself and its directors and officers that it will use due care to
prevent its  officers,  directors,  employees,  counsel,  accountants  and other
representatives  from disclosing such information to any other person or entity;
provided, however, the Investor may disclose or deliver any information or other
material  disclosed  to or received by it should the  Investor be advised by its
counsel  that such  disclosure  or delivery is  required by law,  regulation  or
judicial or  administrative  order.  For  purposes of this Section 5, "due care"
means at least the same level of care that the Investor would use to protect the
confidentiality  of its own  sensitive  or  proprietary  information,  and  this
obligation shall survive termination of this Agreement.


6.         MISCELLANEOUS

           a.         Notices.

                     All  notices,   requests,   demands,   claims,   and  other
communications  hereunder  shall be in  writing.  Any notice,  request,  demand,
claim, or other  communication  hereunder shall be deemed duly delivered two (2)
business days after it is sent by registered or certified  mail,  return receipt
requested,  postage  prepaid,  or one (1)  business  day  after it is sent via a
reputable  nationwide  overnight  courier service,  in each case to the intended
recipient as set forth below:

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If to the Company:                            Copy to:

HemaSure Inc.                                 Battle Fowler LLP
140 Locke Drive                               Park Avenue Tower
Marlborough, MA  01752                        75 East 55th Street
Attn:    President and Chief                  New York, NY  10022
         Executive Officer                    Attn:  Luke P. Iovine, III, Esq.
                                              Fax:  212-856-7816

If to the Investor:                           Copy to:

Sepracor Inc.                                 Hale and Dorr LLP
111 Locke Drive                               60 State Street
Marlborough, MA  01752                        Boston, MA  02109
Attn:    Senior Vice President,               Attn:  John Chory, Esq.
         Finance and Administration           Fax:  617-526-5000


Either party hereto may hereto give any notice, request,  demand, claim or other
communication  hereunder  using any other means  (including  personal  delivery,
expedited  courier,   messenger  service,  telecopy,  telex,  ordinary  mail  or
electronic  mail),  but  no  such  notice,  request,  demand,  claim,  or  other
communication  shall be  deemed  to have been  duly  given  unless  and until it
actually is received by the  individual  for whom it is  intended.  Either party
hereto may change the address to which notices,  requests,  demands,  claims and
other  communications  hereunder  are to be  delivered by giving the other party
hereto notice in the manner herein set forth.

           b.         Survival.

                     All warranties,  representations  and covenants made by the
Investor  and the  Company  herein  or in any  certificate  or other  instrument
delivered  by  the  Investor  or the  Company  under  this  Agreement  shall  be
considered to have been relied upon by the Company or the Investor,  as the case
may be, and shall  survive  all  deliveries  to the  Investor  of the  Purchased
Securities or payment to the Company for the Purchased Securities, regardless of
any investigation made by the Company or the Investor, as the case may be, or on
the Company's or the Investor's behalf.

           c.         Successors and Assigns; No Third-Party Beneficiaries.

                     This Agreement shall inure to the benefit of and be binding
upon the  successors  and  assigns of each of the  parties;  provided,  however,
neither  party hereto shall  assign or delegate any of the  obligations  created
under this  Agreement  without  the prior  written  consent of the other  party.
Nothing in this Agreement  shall confer upon any person or entity not a party to
this

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Agreement,  or the legal representatives of such person or entity, any rights or
remedies of any nature or kind whatsoever under or by reason of this Agreement.

           d.        Entire Agreement; Amendment and Waiver.

                     This  Agreement,  and the  agreements  attached  hereto  as
Exhibits,  constitute  the  entire  understandings  of the  parties  hereto  and
supersede  all prior  agreements or  understandings  with respect to the subject
matter  hereof  among such  parties.  This  Agreement  may be  amended,  and the
observance of any term of this Agreement may be waived, with (and only with) the
written consent of the Company and the Investor.

           e.        Severability.

                     In the event that any part or parts of this Agreement shall
be  held  illegal  or  unenforceable  by any  court  or  administrative  body of
competent  jurisdiction,  such  determination  shall not  effect  the  remaining
provisions of this Agreement which shall remain in full force and effect.

           f.        Paragraph and Section Headings.

                     The  headings  of the  sections  and  subsections  of  this
Agreement  are  inserted  for  convenience  only  and  shall  not be  deemed  to
constitute a part thereof.

           g.        Governing Law.

                     This  Agreement  shall be  deemed  to have been made in the
State  of New  York  and the  validity  of  this  Agreement,  the  construction,
interpretation  and enforcement  thereof,  and the rights of the parties thereto
shall be determined  under,  governed by, and  construed in accordance  with the
internal  laws of the  State  of New  York,  without  regard  to  principles  of
conflicts of law.

           h.        Arbitration.

                     Any  dispute  or  controversy  arising  under,  out of,  in
connection  with,  or in relation  to this  Agreement  or any other  Transaction
Document  shall be determined  and settled by arbitration in New York by a panel
of three (3) members in  accordance  with the  commercial  rules of the American
Arbitration  Association.  Any award rendered therein shall be final and binding
upon the  parties and their legal  representatives,  successors  and assigns and
judgment may be entered in any court having jurisdiction thereof.

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           i.        Counterparts.

                     This Agreement may be executed in one or more counterparts,
each of which shall be deemed an  original  and all of which  together  shall be
considered one and the same agreement.


                         (Signatures on Following Page)

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


                                     HEMASURE INC.


                                     By:/s/ James B. Murphy
                                        ---------------------------------------
                                        Name:  James B. Murphy
                                        Title: Senior Vice President of Finance
                                               and Administration


                                     SEPRACOR INC.


                                     By:/s/ Robert Scumaci
                                        ---------------------------------------
                                        Name:  Robert Scumaci
                                        Title: Senior Vice President of Finance
                                               and Administration


810712.2


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