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                                                                  Exhibit 10.47
                          NON-NEGOTIABLE PROMSSORY NOTE

Maximum Principal Balance                                    St. Louis, Missouri
of $9,500,000                                                    October 8, 1999

            EPIX MEDICAL, INC., a Delaware corporation (hereinafter called
"EPIX"), for value received, hereby promises to pay to MALLINCKRODT INC., a
Delaware corporation (hereinafter called "MALLINCKRODT") the principal sum
outstanding hereunder from time to time, plus accrued interest thereon, in
accordance with the terms and conditions and at the times specified herein
below.

            All payments of principal and interest made pursuant to this
Non-Negotiable Promissory Note ("Note") shall be in such coin or currency of the
United States of America as at the time of payment shall be legal tender for
payment of public and private debts, and shall be made by EPIX to MALLINCKRODT
at its offices at 675 McDonnell Boulevard, P. 0. Box 5840, St. Louis, Missouri
63134, or by wire transfer to MALLINCKRODT in immediately available funds to
such account as MALLINCKRODT may designate in writing to EPIX in advance of any
such payment.

            All capitalized terms used herein, unless otherwise specifically
defined, shall have the meaning ascribed to such terms in the Strategic
Collaboration Agreement among Epix Medical, Inc. (formerly known as Metasyn,
Inc.), Mallinckrodt Inc. (a Delaware corporation and formerly known as
Mallinckrodt Medical, Inc.) and Mallinckrodt Inc. (a New York corporation and
formerly known as Mallinckrodt Group Inc.), dated August 30, 1996, as thereafter
amended from time to time, hereinafter referred as the "Strategic Collaboration
Agreement".

            1. Disbursement of Funds. MALLINCKRODT hereby agrees to loan to
EPIX, on a quarterly basis and in accordance with and subject to the limitations
and procedures set forth herein, such portion of EPIX share of Development Costs
under the Strategic Collaboration Agreement as EPIX shall request from
MALLINCKRODT.

            2. Procedures for Disbursement of Funds. On or about the twentieth
(20th) day of the month following the end of any calendar quarter, beginning
with the calendar quarter commencing on July 1, 1999 and ending on September 30,
1999, EPIX will submit to MALLINCKRODT a written request for a loan of funds for
an amount not to exceed expenditures by EPIX and its subcontractors comprising
EPIX, one-half share of Development Costs for the immediately preceding calendar
quarter, which request shall be accompanied by supporting documentation clearly
demonstrating the amount of Development Costs incurred by EPIX and its
subcontractors in such prior calendar quarter. Supporting documentation in the
form and format of the attached forecast shall be deemed adequate for purposes
hereof. Not later than the fifteenth (15th) day of the month following each
quarter MALLINCKRODT shall submit to EPIX data and supporting documentation
indicating the amount of Development Costs incurred by MALLINCKRODT and its
subcontractors in such prior calendar quarter, such data and


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documentation to be in sufficient detail so as to enable EPIX to make the loan
request referred to herein. Supporting documentation in the form and format of
the attached MS325 budget/forecast shall be deemed adequate for purposes hereof.
MALLINCKRODT shall, subject to any applicable limitations set forth herein,
disburse the funds requested by EPIX on the later of (i) the last day of the
month following the end of any calendar quarter for which a loan of funds is
requested and (ii) ten (10) days after the receipt by MALLINCKRODT of a request
for funds meeting the requirements of this Section. Upon disbursement to EPIX by
MALLINCKRODT of any funds, MALLINCKRODT, at its option, may require EPIX to
execute and deliver (at the expense of EPIX), a new Note adjusting the principal
amount then outstanding, or may present this Note to EPIX for notation hereon of
any additional principal amount outstanding as a consequence of the disbursement
of funds by MALLINCKRODT.

            3. Interest. Any principal amount outstanding hereunder shall bear
interest during any calendar quarter at the prime rate of interest as published
in the Wall Street Journal on the first business day of each calendar quarter,
beginning with the calendar quarter commencing on October 1, 1999, and shall be
calculated with respect to any portion of the principal balance hereunder only
to the extent such portion was outstanding during any quarter, which will be
determined by dividing the number of days during the quarter in which any such
portion of the principal is outstanding by the total number of days in such
quarter. The interest applicable to the outstanding principal amount hereunder
shall be adjusted quarterly in the preceding fashion for so long as any amounts
remain outstanding hereunder.

            4. Limitations on Loan of Funds. Notwithstanding any other provision
hereof, in no event will MALLINCKRODT be required to loan funds to EPIX in
response to any specific request for a loan in an amount that, when added to the
principal amount already outstanding hereunder, would exceed the principal
amount of Nine Million Five Hundred Thousand Dollars ($9,500,000) in the
aggregate. Further, in no event will MALLINCKRODT be required to loan EPIX any
amounts with respect to any given calendar quarter that are in excess of the
lesser of (i) the amount of Development Costs actually incurred by EPIX during
that calendar quarter and (ii) one-half of the aggregate Development Costs
incurred by MALLINCKRODT and EPIX during any such calendar quarter, regardless
of whether or not the amount of Development Costs incurred by MALLINCKRODT
during any such calendar quarter are more or less than the Development Costs
incurred by EPIX during that same calendar quarter. However if, with respect to
any calendar quarter, EPIX has incurred more Development Costs than MALLINCKRODT
then, in accordance with the requirements and intent of the Strategic
Collaboration Agreement and not as a loan or advance of funds hereunder, it is
understood that MALLINCKRODT will reimburse EPIX for one-half (1/2) of the
difference in this amount on the same date on which any loan of funds is made by
MALLINCKRODT to EPIX hereunder to cover the Development Costs incurred by EPIX
for such calendar quarter.

             5. Repayment of Loaned Amounts.


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            (a) The principal hereunder and all unpaid interest accrued thereon
shall be due and payable in full on the earliest to occur of (i) October 1,
2002, (ii) thirty (30) days after the date of the First Commercial Sale of the
Licensed Product in the Territory and (iii) thirty (30) days after the first
date upon which EPIX could reasonably repay all outstanding principal and
interest hereunder without creating any reasonably foreseeable risk that EPIX
will be entitled to receive a loan from MALLINCKRODT pursuant to Section 8.5 of
the Strategic Collaboration Agreement within six (6) months after the date of
any such repayment. If the outstanding principal and accrued interest under this
Note are not repaid in full by EPIX, without demand, presentment or notice by
MALLINCKRODT of any kind (all of which are expressly waived by EPIX to the
extent permitted by applicable law), as and when due in accordance with the
immediately preceding sentence, then, in addition to any other rights or
remedies MALLINCKRODT may have in accordance with the terms hereof, MALLINCKRODT
shall have the right, effective upon written notice to EPIX, to withhold and
retain up to fifty percent (50%) of the Operating Margin for any given calendar
quarter otherwise payable to EPIX in accordance with Section 8.6 of the
Strategic Collaboration Agreement until such time as all outstanding amounts of
principal and interest hereunder are completely paid.

            (b) Notwithstanding the immediately preceding subsection (a), for so
long as there is any principal amount outstanding hereunder, EPIX will repay to
MALLINCKRODT twice per year, on or before July 15 and January 15, all interest
accrued during the previous six month period.

            6. Security for Repayment. Repayment of this Note shall be secured
by an interest in all of the intellectual property assets of EPIX ("Secured
Assets"), including (without limitation) all patents, applications for patents,
trademarks, trademark applications, trade secrets and confidential or
proprietary scientific and technical information and data, whether owned by EPIX
or which EPIX has the right to employ by way of license or other grant (and, in
such case, as permitted by and subject to the terms and conditions of, such
license or grant), and as more fully described in and in accordance with the
terms of that certain Security Agreement between MALLINCKRODT and EPIX attached
hereto as Exhibit I and expressly made a part hereof (the "Security Agreement").
EPIX affirms that (i) the security interest granted in this Note and in the
Security Agreement is and shall remain a right of first priority senior to the
interests of all other creditors of EPIX with respect to the Secured Assets
until such time as it is released by MALLINCKRODT or as a consequence of payment
of all amounts secured hereunder, (ii) that such security interest is not
secondary or subordinate in any respect to the rights of any creditor or any
other party and (iii) that no other party has any security interest, collateral
interest or lien in, on or with respect to the Secured Assets.

            7. Loss, Theft, Destruction or Mutilation of Note. Upon receipt of
evidence reasonably satisfactory to EPIX of the loss, theft, destruction or
mutilation of this Note, and, in the case of any such loss, theft or
destruction, upon receipt of an affidavit of loss and indemnity from
MALLINCKRODT reasonably satisfactory to EPIX, or, in the case of any such
mutilation, upon surrender and cancellation of this Note, EPIX will make and
deliver, in lieu of this Note, a new Note of like tenor and unpaid principal
amount and


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dated as of the original date hereof.

            8. Prepayment. Upon notice given to MALLINCKRODT, EPIX may, at its
option and without penalty of any kind, prepay the Note, in whole or in part,
together with interest accrued thereon to the date of such prepayment. Upon any
prepayment of a portion of the principal amount of this Note, MALLINCKRODT, at
its option, may require EPIX to execute and deliver (at the expense of EPIX), a
new Note for the principal amount of this Note then remaining unpaid, or may
present this Note to EPIX for notation hereon of the payment of the portion of
the principal amount and any interest so prepaid.

            9. Covenants. EPIX covenants and agrees that, so long as the Note or
any replacement therefor shall be outstanding;

            (a) EPIX will promptly pay and discharge or cause to be paid and
discharged, before the same shall become in default, all lawful taxes and
assessments imposed by any state, local or federal governmental authority upon
EPIX or any subsidiary or upon the income and profits of EPIX or any subsidiary,
or upon any property, real, personal or mixed, belonging to EPIX or any
subsidiary, or upon any part thereof, as well as all lawful claims for labor,
materials and supplies which, if unpaid, might become a lien or charge upon the
Secured Assets; provided, however, that neither EPIX nor any subsidiary shall be
required to pay and discharge or to cause to be paid and discharged any such
tax, assessment, charge, levy or claim so long as EPIX or its subsidiary (as
appropriate) shall be contesting the validity thereof in good faith by
appropriate proceedings or EPIX shall, in its good faith judgment, deem the
validity thereof to be substantially in question.

            (b) EPIX will at all times maintain and keep, or cause to be
maintained and kept, in good status and condition all significant properties and
rights of EPIX and its subsidiaries which are included in the Secured Assets
(including maintenance of fees for filing or registration due and payable with
respect to all registrable intellectual property rights included in the Secured
Assets); provided, however, that nothing in this paragraph (b) shall prevent the
abandonment or termination of any rights (including, but not limited to, the
abandonment of any claims under any existing or future patent applications
included in the Secured Assets) if such abandonment or termination is, in the
good faith business judgment of EPIX, in the best interest of EPIX and does not
prejudice MALLINCKRODT in any material respect.

            (c) EPIX will deliver to MALLINCKRODT on a regular basis, but no
less often than quarterly, an accurate copy of its financial statements. EPIX's
EDGAR filing of its reports on Form 10-K and Form 10-Q with the Securities and
Exchange Commission shall be deemed to constitute compliance by EPIX with its
obligations under this Section 9(c).

            (d) EPIX will at all times keep, and cause each of its subsidiaries
to keep, proper books of record and account in which proper entries will be made
of its transactions in accordance with generally accepted accounting principles
consistently


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applied.

            (e) EPIX will do or cause to be done all things necessary and lawful
to preserve and keep in full force and effect its corporate existence, rights
and franchises and the corporate existence, rights and franchises of each of its
subsidiaries; provided, however, that nothing in this paragraph (e) shall
prevent (i) a consolidation or merger of, or a sale, transfer or disposition of
all or any substantial part of the property and assets of EPIX not prohibited by
the provisions of paragraph (f) set forth immediately below, or (ii) the
abandonment or termination of any rights or franchises of EPIX, or the
liquidation or dissolution of, or a sale, transfer or disposition (whether
through merger, consolidation, sale or otherwise) of all or any substantial part
of the property and assets of any subsidiary or the abandonment or termination
of the corporate existence, rights and franchises of any subsidiary if such
abandonment, termination, liquidation, dissolution, sale, transfer or
disposition is, in the good faith business judgment of EPIX, in the best
interests of EPIX and does not prejudice MALLINCKRODT in any material respect.

            (f) EPIX will not consolidate or merge with or into, or sell or
otherwise dispose of all or substantially all of its property to, any other
corporation or other entity, unless:

            (i) the surviving corporation or other entity (if other than EPIX)
      shall expressly and effectively assume in writing the due and punctual
      payment of the principal of and interest on the Note, and the due and
      punctual performance and observance of all the terms, covenants,
      agreements and conditions of this Note and the Security Agreement to be
      performed or observed by EPIX to the same extent as if such surviving
      corporation had been the original maker of the Note,

            (ii) EPIX or such other corporation or other entity shall not
      otherwise be in default in the performance or observance of any material
      covenant, agreement or condition of the Note or of the Security Agreement,
      and

            (iii) MALLINCKRODT shall have received, in connection therewith and
      immediately prior to the closing of such transaction, an opinion of
      counsel for EPIX (or other counsel satisfactory to MALLINCKRODT), in form
      and substance satisfactory to MALLINCKRODT, to the effect that any such
      consolidation, merger, sale or conveyance and any such assumption complies
      with the provisions of clause (i) of this paragraph (f).

            10. Events of Default. If any one or more of the following events,
herein called "Events of Default," shall occur, for any reason whatsoever, and
whether such occurrence shall, on the part of EPIX or any subsidiary, be
voluntary or involuntary or come about or be effected by operation of law or
pursuant to or in compliance with any judgment, decree or order of a court of
competent jurisdiction or any order, rule or regulation of any administrative or
other governmental authority:


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            (a) default shall be made in the payment of the principal or
interest of this Note when and as the same shall become due and payable in
accordance with the terms provided herein, or

            (b) default shall be made in the due observance or performance of
any other covenant, representation, warranty, condition or agreement on the part
of EPIX to be observed or performed pursuant to the terms hereof or pursuant to
the Security Agreement and such default shall continue for thirty (30) days
after receipt of written notice thereof from MALLINCKRODT, specifying such
default and requesting that the same be remedied, or

            (c) the entry of a decree or order for relief by a court having
jurisdiction in respect of EPIX or any subsidiary in any involuntary case under
the federal bankruptcy laws, as now constituted or hereafter amended, or any
other applicable federal or state bankruptcy, insolvency or other similar laws,
or appointing a receiver, liquidator, assignee, custodian, trustee, sequestrator
(or similar official) of EPIX or any subsidiary or for any substantial part of
any of their property, or for all or any portion of the Secured Assets, or
ordering the winding-up or liquidation of any of their affairs and the
continuance of any such decree or order unstayed and in effect for a period of
sixty (60) days, or

            (d) the commencement by EPIX or any subsidiary of a voluntary case
under the federal bankruptcy laws, as now constituted or hereafter amended, or
any other applicable federal or state bankruptcy, insolvency or other similar
laws, or the consent by any of them to the appointment of or taking possession
by a receiver, liquidator, assignee, trustee, custodian, sequestrator (or other
similar official) of EPIX or any subsidiary or for any substantial part of their
property, or for all or any portion of the Secured Assets, or the making by any
of them of any assignment for the benefit of creditors, or

            (e) any default, as defined in any instrument evidencing or under
which EPIX or any subsidiary has outstanding at the time any indebtedness for
money borrowed in excess of $75,000 in aggregate principal amount, shall occur,

then, MALLINCKRODT may, at its option, by notice to EPIX, declare this Note to
be, and all principal outstanding under this Note shall thereupon be and become,
forthwith due and payable in full, together with interest accrued thereon,
without presentment, demand, protest or further notice of any kind, all of which
are expressly waived by EPIX to the extent permitted by law.

            11. Suits for Enforcement. In case any one or more of the Events of
Default specified in Section 10 of this Note shall occur and be continuing,
MALLINCKRODT may proceed to protect and enforce its rights by suit in equity,
action at law and/or by other appropriate proceeding, whether for the specific
performance of any covenant or agreement contained in this Note or in aid of the
exercise of any power granted in this Note, or may proceed to enforce the
payment of this Note or to enforce


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any other legal or equitable right hereunder. In case of any default under this
Note, EPIX will pay to MALLINCKRODT such amounts as shall be sufficient to cover
the costs and expenses of MALLINCKRODT directly attributable to said default,
including, without limitation, collection costs and reasonable attorneys' fees,
to the extent actually incurred.

            12. Remedies Cumulative. No remedy herein conferred upon
MALLINCKRODT is intended to be exclusive of any other remedy and each and every
such remedy shall be cumulative and shall be in addition to every other remedy
provided hereunder or now or hereafter existing at law or in equity.

            13. No Waiver. No course of dealing between EPIX and MALLINCKRODT or
any delay on the part of MALLINCKRODT in exercising any rights hereunder on any
occasion shall operate as a waiver of its rights hereunder to insist on strict
compliance with the terms hereof or to exercise any available remedy on any
future occasion.

            14. Governing Law. This Note shall be construed to be a contract
made under and pursuant to the laws of New York and all of the terms, covenants
and conditions contained herein shall be governed by and construed in accordance
with such laws without giving effect to the conflict of laws principles
contained in such laws.

            15. Miscellaneous.

            (a) The headings of the sections and paragraphs of this Note are
inserted for convenience only and do not constitute a part of this Note.

            (b) This Note, and all supplements, amendments or notations with
respect thereto, shall inure to the benefit of and be binding upon EPIX and its
successors and assigns, but this Note may not be assigned, transferred, pledged
or hypothecated by EPIX without the advance written consent of MALLINCKRODT, and
this Note may not be assigned, transferred, pledged or hypothecated by
MALLINCKRODT (other than to an affiliate) without the advance written consent of
EPIX.

            (c) The invalidity or unenforceability of any term or condition
hereof shall not affect the validity or enforceability of any other term or
condition hereof or of this Note as a whole.

            (d) In the event of any conflict or inconsistency between the terms
of this Note and those of the Security Agreement, the former shall prevail.

            16. Validity. The execution and delivery of this Note and the
Security Agreement and the performance by EPIX of its obligations hereunder and
thereunder have been duly authorized by all requisite corporate action by EPIX
and will not violate any provisions of law, any of the corporate governing
documents of EPIX or any provisions of any indenture, agreement or other
instrument to which COMPANY or any of its assets is bound. This Note has been
duly executed and delivered by EPIX and constitutes the legal, valid and binding
obligation of EPIX, enforceable against EPIX in


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accordance with its terms. The execution and delivery of this Note and the
performance by EPIX of its obligations hereunder and under the Security
Agreement does not and will not violate any judicial decree or order applicable
to EPIX.

            IN WITNESS WHEREOF, EPIX MEDICAL, INC. has caused this Note to be
signed in its corporate name by one of its officers thereunto duly authorized
and to be dated as of the date and year first above written.

                                          EPIX MEDICAL, INC.


      By: /s/ Michael D. Webb
          ---------------------
                                          Michael D. Webb, President


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