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                                                                EXHIBIT 10.55

NOTE: The following Commercial Factoring Agreement, as amended, is translated
from Spanish. The following is a fair and accurate English translation.

                                        /s/ LARRY W. SMITH
                                        Corporate Secretary

No. 2.833


                         COMMERCIAL FACTORING AGREEMENT

This agreement is made in Madrid, on May 21, 1996, certified by the Public
Stockbroker, Mr. Carlos J. Torres Diz.


                                    BETWEEN

OF THE FIRST PART: SANTANDER DE FACTORING, S.A., ENTIDAD DE FINANCIACION,
entered under number 6 on the Special Register of the Directorate General for
the Treasury and Financial Policy as a financial institution specializing in
factoring. It was incorporated by means of a public deed certified by the Notary
Public of the Association of Notaries Public of Madrid, Mr. Antonio Vazquez
Presado, on May 30, 1986 under number 2,114 of his records. The company has its
registered offices in Madrid, Plaza de Manuel Gomez Moreno no. 2, Edificio
Alfredo Mahou (Postal District 28020). The company's Tax Identification Code
(N.I.F.) number is A-78/287582. It is entered on the Madrid Commercial Register
-1, volume 1,034 general, 1001 of section three of the Companies Register, folio
55, sheet number 70,685-1, first entry. The company is represented in the
execution of this agreement by Mr. Javier Rodriquez-Mantinan, attorney in fact 
of Banco Santander by virtue of a deed of power of attorney conferred on the 
said bank by the company (hereinafter referred to as "the FACTOR") before the 
Notary Public of the Association of Notaries Public of Madrid, Mr. Roberto 
Parejo Gamir, on May 18, 1993, under number 1,000 of his records. The power of
attorney is entered at the Madrid Commercial Registry.

OF THE OTHER PART: NEXTAR FARMACEUTICA, S.A., a company incorporated by virtue
of a public deed certified by the Notary Public of the Association of Notaries
Public of Madrid, Mr. Jose Maria Alvarez Vega, on December 17, 1993, under
number 7,553 of his records. The company is entered in volume 7,553 of the
Madrid Commercial Register and its Tax Identification Code (N.I.F.) number is
A-80754799. Its registered offices are located at Paseo de la


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Castellana, 139, Madrid. It is represented in the execution of this agreement by
Mrs. Mercedes Garica Bravo, a Director and attorney in fact of the company by
virtue of a deed of power of attorney conferred on him by the company before the
Notary Public of the Association of Notaries Public of Madrid, Mr. Jose Maria
Alvarez Vega, on December 30, 1993, under number 5,367 of his records. The power
of attorney is entered at the Madrid Commercial Registry.

(This latter party shall hereinafter be referred to as "THE CLIENT").

                           THEY DO HEREBY STATE THAT

1.-The FACTOR is a factoring company included in the Order of May 13, 1981, of
the Ministry for the Economy, issued by virtue of the authorization contained
in Royal Decree 896/1977, of March 28, and its main purpose consists of credit
collection management operations and advance payment of funds thereon, to
which the said provisions refer.

2.-The CLIENT carries out the commercial activities included in its corporate
purpose and is interested in arranging with the FACTOR the performance of
factoring services in connection with the commercial operations that it carries
out with its clients.

3.-Both institutions, through their respective representatives, have decided to
make and, in this act, do hereby make a factoring agreement, for which purpose
they consent to the following

                                    CLAUSES

ONE.-PURPOSE OF THIS AGREEMENT.

The purpose of this agreement is the assignment of all credits and rights held
by the CLIENT vis-a-vis the entities (hereinafter referred to as DEBTORS) listed
in annex number 1 hereto, by virtue of commercial transactions that the CLIENT
has carried





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out or that it may carry out from the date hereof, with the following 
exceptions:

1. - Purchases, sales or other commercial transactions with a cash price.

2. - Deliveries of merchandise in respect of a purchase and sale agreement
subject to any condition, or transactions of other types subject to any 
condition.

Without prejudice to that established above, the assignment of the credits and
rights that the CLIENT holds vis-a-vis DEBTORS that, at the date hereof, are
not included in Annex no. 1 hereto may be subject to the agreement, provided
that the FACTOR expressly accepts the assignment of the said credits. For these
purposes, the FACTOR, after carrying out such analyses as it may see fit, shall
approve or otherwise all the DEBTORS proposed by the CLIENT. Approval, as
appropriate, or rejection by the FACTOR, as assignee of the credits charged to
the DEBTOR, shall be indicated by notice given by the FACTOR to that effect in
any of the forms established in point one of Clause twelve hereof.

The CLIENT assigns to the FACTOR its credits and such rights as may derive from
agreements made by it with its DEBTORS, including that of termination, as 
appropriate.

The assignment of credits referred to in the preceding section is governed by
this agreement and, in that not provided herein, by articles 347 and 348 of the
Commercial Code and, in a subsidiary manner, by articles 1,529 and articles
concerning the same matter of the Civil Code and article 101 and articles
concerning the same matter of the Public Administration Contracts Act, Act
13/1995 of May 18.

The CLIENT guarantees, under its liability, the effectiveness, legitimacy,
validity, transferability and enforceability of all the credits assigned,
whatever their type (certificates invoices, provisional and final settlements,
etc.) declaring that both the credit and the cause from which it derives
conform to the rules currently in force and to the principles of the Legal
System for Public Contracts applicable to the DEBTOR Administration, regarding
its preparation and legality, regarding both execution and liquidation. It
likewise guarantees that the public rules governing the legal system for
credits themselves and their cause have been fulfilled.

The CLIENT likewise guarantees, under its liability, that there is no 
encumbrance,

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incident or conduct relating to the agreement giving rise to the credit, its
cause or the credit itself that allows the validity, amount and full or partial
enforceability of the assigned credit to be affected or damaged.

Any infringement or default of this agreement shall be considered to damage the
presupposed objectives of the assignment of the credit, annulling its validity
or being permitted to be considered as sufficient default of the agreement on
the part of the CLIENT, thus conferring on the FACTOR the right to receive the
amount paid in advance on account of such credits, together with any loss and
damage that it may have incurred due to the assignment that is resolved to be
invalid or annulled.

The CLIENT is likewise liable for the solvency of the DEBTORS and states that
under no circumstances have the said credits been assigned to any other
institution.

The CLIENT agrees, in the terms provided in clause two hereof, to inform the
DEBTORS listed in annex number 1, from the date when this contract is made,
that the payment of their obligation shall only be considered legitimate if it
is made to the FACTOR, in the capacity that it holds.

Without prejudice to the provisions contained in the following clause, the
FACTOR shall furnish to the CLIENT notice of the assignment of the credits,
which the CLIENT must send to its DEBTORS. The CLIENT shall deliver to the
FACTOR a copy of the instrument that is sent.


2. - RECORDING OF THE ASSIGNMENT OF CREDITS.

A) With regard to the credits arising from the date of execution hereof:

1. - The CLIENT agrees to deliver to the FACTOR, within a maximum term of 30
days from the date of their creation, documents proving the credits assigned.
For this purpose, it shall send to the FACTOR, within the time-limit stated
above, a letter of assignment conforming to annex number 2 hereof and, together
with the said letter, original copies of the invoices pertaining to the credits
assigned.

The letter of assignment referred to in the preceding section, and the
originals and original copies of the invoices must be signed by a person with
sufficient power of


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attorney to represent the CLIENT. This person's signature must be included on
the sheet of authorised signatures attached hereto as annex number 3.

The CLIENT shall likewise include delivery notes and/or such other commercial
documents, including, as appropriate, bills of exchange -whether accepted or
otherwise-, promissory notes or commercial drafts issued, in accordance with
that established in the second Particular Condition hereof.

This Particular Condition shall not be of a restrictive nature and the FACTOR,
as appropriate, may therefore demand from the CLIENT any other document
relating to each credit assigned that is not included in the said condition and
that proves or represents the credits assigned. Similarly, by means of notice
to that effect to the CLIENT, the FACTOR may, in certain cases, alter or remove
any of the documents that, at the date of execution hereof, are established in
the said particular condition.

2.-The CLIENT likewise agrees:

2.1.-To include the following expression in the agreements that it makes with
the DEBTORS included in the scope hereof, in its delivery notes that in such
invoices as it may issue to its DEBTORS:

"the credit right to demand the price of this merchandise or these services has
been assigned, within the framework of a factoring agreement, to SANTANDER DE
FACTORING, S.A., with registered offices in Madrid, (Postal District 28020),
Plaza de Manuel Gomez Moreno 2, "Edificio Alfredo Mahou", and therefore the
purchaser shall only be released from its payment obligation by paying the
amount of this invoice or bill to the said assignee in its current account
number 2,740 of branch 0533, Madrid, of BANCO SANTANDER."

3.-The obligations assumed by the FACTOR hereunder may only be enforced when
the FACTOR has received from the CLIENT the letter of assignment referred to in
section 1 above, a copy of the invoice authorised by the signature of the
CLIENT and the FACTOR in the terms provided in sections 1 and 2 above and such
other documents as are stated in the second particular condition hereof. In any
case, each credit assigned must fulfil all the conditions established herein,
and in particular those relating to the deferment of payment agreed with the
DEBTORS, as is described in Annex no. 1.


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The FACTOR shall immediately send to the CLIENT acknowledgement of receipt of
these documents and of the consequent consummation of the assignment of the
credits to which they refer.

B) With regard to the credits that have originated prior to the date of
execution hereof:

For these purposes the CLIENT must send to the FACTOR the letter of assignment
referred to in the preceding sections, along with the original copies of the
invoices giving rise to the assigned credits. Nevertheless, without prejudice
to the assignment in favour of the FACTOR, payment shall only be advanced on
the said credits, in accordance with the provisions contained in section 3 of
the following clause, once the FACTOR has proof that the invoice or invoices
proving the credits are registered at the DEBTOR's Accounts Department and have
been approved.

3.-FACTORING SERVICES.

The FACTOR agrees with the CLIENT to provide it with the following services:

1.-The FACTOR shall take responsibility for managing the collection of the
assigned credits.

The FACTOR does not assume the risk of insolvency on the part of the DEBTORS.
Therefore, the debts accumulated by a debtor with the FACTOR shall be demanded
by the FACTOR, but this latter shall not assume the risk of insolvency on the
part of the DEBTOR, so that non-payment of these credits by the DEBTOR shall
allow the FACTOR to withhold payment of the amount of the same to the CLIENT,
without prejudice to the fact that it may manage their collection in the terms
established herein.

The CLIENT agrees to place immediately at the FACTOR's disposal any commercial
drafts or any other methods or instrument of payment issued by the DEBTORS for
credits assigned by the CLIENT to the FACTOR that the DEBTORS may have sent or
delivered directly to the CLIENT.

2.-The FACTOR agrees to pay the CLIENT the amount of the credits assigned, for
which payment has not been advanced, after deducting the counter-payment 
established





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herein, on the working day after the day when the FACTOR pays in the amount of
the credit.

3.- The FACTOR may advance to the CLIENT an amount up to the percentage,
established in the sixth particular condition, of the total amount of the
credits assigned although under no circumstances may the total amount of the
advance payment exceed the amount stated in section a) of the fourth Particular
Condition hereof.

For this advance payment, the CLIENT shall pay to the FACTOR the interest
provided in the first Particular Condition hereof in the manner established in
clause six.

When these credits have been paid, the FACTOR shall be reimbursed for the
advance payment that it has made.

The CLIENT shall acknowledge receipt of notices made to it by the FACTOR
relating to the credits selected by this latter for advance payment of their
amounts.

The FACTOR shall exclude the following credits from the advance payment:

a) Credits that the FACTOR has not collected within a term of three hundred and
sixty-five days (365), reckoned from the date of their assignment.

b) Credits regarding which the DEBTOR has filed any exception, either in or out
of

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Court, based on its causal relationship with the CLIENT, whatever agreement or
legal link exists in the relationship between the CLIENT and the DEBTOR.

In the event that the credit subject to advance payment has not been paid by
the DEBTOR when the term referred to in section a) above has expired and/or in
the event that the credit paid in advance is included in the case contemplated
in section b) above, the FACTOR shall replace the credit subject to advance
payment by one or more other credits, up to its full amount and, as
appropriate, the amount of the interest payable, by means of the appropriate
notices to the CLIENT, or it shall choose to demand from this latter immediate
reimbursement of the advance payment, with such surcharges as may be payable,
as appropriate.

FOUR.-COLLECTION OF CREDITS.

1.- In view of its capacity as legitimate assignee of the credits, for the
purposes of collection of the same, the FACTOR shall be authorised and
expressly empowered by the CLIENT, as widely as possible in Law, during the
full period in force hereof, to issue, endorse, collect or by any other means
certify any commercial drafts of traffic or trade as may be issued for payment
of the assigned credits.

2.- In the event that any debtor should incorrectly pay the CLIENT the credit
assigned, this latter agrees to deliver the amount incorrectly collected to the
FACTOR immediately; in any case, the said sum may never be offset by any sum
that the FACTOR may owe to the CLIENT in any respect. The CLIENT shall be
considered as a mere depository of the amount received for the minimum time
necessary for its reimbursement to the FACTOR. The above is without prejudice
to the fact that the FACTOR may bring any action against the DEBTOR to claim
legitimate payment.

3.- In cases where the DEBTOR fails to pay the credit that the FACTOR demands
of it, arguing causes that are based on its relationship with the CLIENT 
- whether or not such causes concern the purchase and sale agreement that gave
rise to the credit-, the FACTOR shall notify the CLIENT of the reasons that the
DEBTOR has given and, acting on instructions from the CLIENT, it shall defend
its right to receive the credit, either in or out of court. The extra-judicial
or judicial claim conform with the system provided in this agreement and, in
particular, in the provisions contained in the following section.

4.- Should the DEBTOR file against the FACTOR, when this latter attempts, by





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extra-judicial means, to collect a credit, any exception referring to its
relationship with the CLIENT, the FACTOR shall immediately notify the CLIENT of
such circumstance. The FACTOR shall thenceforth act on instructions that it
receives from the CLIENT in order to achieve payment of the credit in question
and it shall exercise, in its own name but on behalf of the CLIENT, such act
as, by mutual agreement, they may decide on for settlement of the credit.
Should such actions mean the institution of any judicial proceedings, the FACTOR
may demand that the CLIENT deliver to it an amount in respect of a provision of
funds.

If, when a dispute with the DEBTOR has arisen, the CLIENT and the FACTOR should
fail to reach agreement on what actions must be brought, when three months have
passed from the notice by the FACTOR to the CLIENT or the exception filed by
the DEBTOR the FACTOR may withdraw the credit and shall be released from any
other obligation. Such withdrawal of the credit shall not confer on the CLIENT
any right whatsoever to demand refund of the counter-payments agreed herein
deriving from by the original assignment, the services provided by the FACTOR
or any other service contemplated herein.

In any event, when one year has passed from when the FACTOR notified the CLIENT
of the fact of the DEBTOR's non-payment, for any reason other than insolvency
on the part of the DEBTOR, should the credit continue outstanding and should no
judicial proceedings whatsoever have been instituted for its collection, the
FACTOR may withdraw the credit from the CLIENT, who shall once again become
the legitimate holder of the same, the FACTOR being released from any other
obligation. Such withdrawal of the credit shall not confer on the CLIENT any
right whatsoever to demand the refund of the counter-payments agreed herein
deriving by the original assignment, the services provided by the FACTOR or any
other service contemplated herein.

FIVE. - OTHER RIGHTS AND OBLIGATIONS OF THE FACTOR AND THE CLIENT.

1.- The CLIENT may agree with its DEBTOR to issue a credit note in the event
that the invoice originally issued includes, by error, a greater amount of
merchandise than was actually supplied. There may be any other cause for a
credit note. Whenever a credit note is issued, the CLIENT shall be obliged to
notify that fact to the FACTOR within ten days from the issue of the said
note by sending it a copy of the document that was sent to the DEBTOR. The
FACTOR, provided that it is notified a sufficient length of time in advance,
shall notify the DEBTOR that the invoice has been reduced by the amount of the
credit note.



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2.- The FACTOR may, at any time, examine the CLIENT's administrative and
accounts books and documents, through a person expressly authorized for that
purpose, who is bound by professional secrecy. The FACTOR expressly accepts
that the said examination be carried out by the CLIENT's external auditor,
provided that such auditor is of acknowledged prestige. The only purpose of
granting this right to examine the CLIENT's books is to guarantee to the FACTOR,
who is actually the assignee of all the credits, that the CLIENT is the holder
as a result of its relationship with the DEBTORS listed in annex number 1, with
no exceptions other than those provided in clause one hereof.

3.- The CLIENT shall be obliged to place at the FACTOR's disposal, at this
latter's request, when the annual accounts have been approved and deposited at
the Commercial Registry, a copy of the said accounts, the management report and
the auditor's report when the CLIENT, due to circumstances established in Law,
is obliged to submit the said auditors' report.

4.- If the DEBTOR is a public body or institution, the CLIENT shall assume
responsibility for any denouncement and intimation due to delay in payment of
over two months, referred to in the articles of the State Contracts Act, and the
FACTOR shall have no liability whatsoever for the omission of such, even though
the credits are formally transferred.

SIXTH - COUNTERPRESENTATION IN FAVOR OF FACTOR

1. Commission

At the time, and in conformity of the present contract, that the granting of
each credit, and in respect to the first credits given up to the amount of six
hundred million pesetas the FACTOR will earn the commission established under
condition third, given that (a) it will be applied to the whole amount of the
credit granted, including: the taxes generated by the operation of the above
mentioned credit.

Once the amount of six hundred million pesetas is reached the FACTOR will earn
the commission established under the third condition, numeral (b) applicable to
the whole amount of the credit granted including taxes generated by the
operation.

The amount of the commission owed to the FACTOR will be considered earned and
payable from the moment that the credit is granted, given this the FACTOR can
compensate the amount against any debits that at the moment they could have
against the CLIENT.

The FACTOR will earn the commission, having the option to credit the account
that they called "Prepaid Payment" to which is made reference in the Seventh
stipulation or credit the amount to the current account or credit account of
the CLIENT referenced in Condition Fifth.

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the amount in the CLIENT's current or credit account referred to in the fifth
Particular Condition.

2.-Interest:

Should the CLIENT claim advance payments from the FACTOR, the CLIENT shall be
obliged to pay interest to the FACTOR, accrued on a day-to-day basis at an
annual rate based on a year of 360 days, as stated in the first Particular
Condition, for the period between the date of the said advance payment and the
date when the FACTOR is reimbursed for the full amount of the credit paid in
advance, both inclusive.

Interest shall be settled per month in arrears, making the settlement coincide
with the last day of each calendar month. The first settlement may refer,
therefore, to a period of less than one month, whereas successive settlements
shall refer to the calendar month ending on the day for settlement of interest.
The settlement shall be carried out according to the average balance of advance
payments during the period subject to settlement.

The interest rate referred to in the first particular condition may be reviewed
at any time by the FACTOR due to alterations in the interest rate on the
interbank market, and it may in any case be reviewed quarterly.

The review, which shall affect the balance of advance payments drawn down at
that moment, must be notified to the CLIENT, which must give notice of its
acceptance or rejection of the new interest rate proposed by the FACTOR. In
this latter case, non-acceptance by the CLIENT of the rates of interest
proposed by the FACTOR shall mean that the CLIENT waives the possible advance
payment of the amount of other credits until the CLIENT expressly accepts the
rates successively notified by the FACTOR.

Any alteration in the nominal rate of interest shall give rise to the
corresponding alteration in the TAE calculated in the manner stated in the
first Particular Condition.




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SEVEN. - ACCOUNTS

1. - Accounts relating to this agreement

For the purposes hereof, the CLIENT and the FACTOR shall keep two special
accounts to which all debts that may arise between the parties both in the act
of execution of this agreement and in the course of its performance shall be
charged and paid.

The first account, with the name of "collateral" shall function as follows: the
account shall be credited with the assignment of credits by the CLIENT to the
FACTOR and debited when the said credits are collected by the FACTOR. The
second account, with the name of "advance payments" shall function as follows:
amounts collected by the FACTOR shall be credited to the account and the
account shall be debited with the funds that the FACTOR sends to the CLIENT and
other counter-payments or costs that may accrue charged to the CLIENT. The
average debit balance of this second account of "advance payments" shall
represent the advance payments for the purposes of the provisions contained in
section 2 of clause six.

2. - Execution:

For the purposes of the provisions contained in article 1,435 of the Civil
Procedural Act, the parties hereto expressly agree that the assessment to
establish the debt to be claimed in enforcement proceedings shall be carried out
by the FACTOR, issuing the appropriate certificate that contains the balance of
the special accounts at the closing date. By virtue of this, it shall be
sufficient for the exercise of enforcement action to submit this agreement
together with the certificate contemplated in article 1,429, number 6 of the
Civil Procedural Act and to furnish another certificate, issued by the FACTOR,
of the balance charged to the CLIENT. The said certificate shall state the
Broker acting at the FACTOR's request and that the said balance coincides with
the balance of the account opened for the CLIENT and that the assessment of the
debt has been carried out in the manner agreed herein.

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EIGHT - COSTS AND TAXES

1. - Taxes:

All taxes, rates, stamps and any other encumbrance of the State, 
Autonomous Communities, provinces or localities of any other type, of whatever
nature, class or type, without any limit whatsoever, that, either at present or
in future, may be levied, as appropriate, for the execution, performance and
cancellation of this agreement shall be at the CLIENT's expense.

2. - Costs:

All costs derived from the execution, certification and recording of this
agreement shall also be at the CLIENT's expense. In particular, the fees of the
public certifying official acting in the operation and the costs (including the
fees and expenses of lawyers and Court Solicitors) caused in the event that the
FACTOR demands fulfilment of this agreement shall be payable by the CLIENT.

3. - Settlement of taxes and costs:

Taxes and costs that, as appropriate, may have been paid by the FACTOR or that
may have accrued to it, shall be reimbursed to it by the CLIENT within two
working days, when the FACTOR submits an assessment of the same to the CLIENT,
giving reasons for such.

NINE. - PAYMENTS

1. - Place and method of payment:

On each date when the CLIENT must, in accordance with the provisions contained
herein, pay to the FACTOR any amount in respect of any item, the CLIENT
expressly and irrevocably authorises the FACTOR to debit the relevant amounts to
the current or credit account in the Banco Santander referred to in Particular
Condition number five (or to any other account that the CLIENT may hold in Banco
Santander, even though such account is not expressly mentioned in the said
condition). The CLIENT

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agrees to make sufficient provision of funds in the said accounts.

On each date when the FACTOR must, by virtue of this agreement, pay any amount
to the CLIENT, it shall do so by a payment into the account stated in the
preceding section.

2.-Compensation:

The CLIENT, without prejudice to any other clause hereof, irrevocably
authorizes the FACTOR to apply to the payment of any amount that the CLIENT
owes to it and that is due, any amount from any credit belonging to the CLIENT
that may be in the possession of the FACTOR or that this latter must pay it,
deriving from any type of operation.  For this purpose, the CLIENT also
irrevocably authorizes the FACTOR to carry out any operation or activity that
may be necessary to apply the said amounts to the payment of the sums owed.

TEN.-DURATION

Without prejudice to the provisions contained in the following clause, this
agreement shall have a duration of one year, reckoned from its date of
execution.  When the said term has expired, the agreement should be considered
as extended for successive periods of like duration, unless either of the
parties state a wish to the contrary fifteen days in advance of the initial
expiry date or the expiry date of any extension hereof.  Nevertheless, after
the first year in force, the agreement may be terminated at any time at the
wish of either party, provided that at least fifteen calendar days' advance
notice is given.

Should this agreement be cancelled normally, the FACTOR shall retain the
obligations imposed on it hereunder with regard to the collection of credits
outstanding and to payment, as appropriate, of their amount to the CLIENT who,
in turn, shall be obliged to make the counter-payments outstanding at the
moment when the agreement is cancelled.





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<PAGE>   15
ELEVEN. - PREMATURE TERMINATION OF THE AGREEMENT.

The FACTOR may, at any time, without prejudice to the term stated in the
preceding clause, consider the agreement as terminated when any of the
following circumstances occur:

A).- Termination due to reduction in the CLIENT's solvency: the CLIENT's
solvency shall be considered to be reduced, thus giving rise to a right on the
part of the FACTOR in prematurely terminate this agreement, giving notice of
this to the CLIENT, should the CLIENT carry out or, even without any fault on
its part, be affected by any of the following:

1.- If the CLIENT submits an application to be declared in suspension of
payments or bankrupt or if an application is submitted by a third party and is
accepted by a judicial ruling, or if the CLIENT is subject to judicial
administration or if it is subject to confiscation of its assets or if the
CLIENT acknowledges its inability to meet its debts when due or if
renegotiation of all or some of its payment liabilities is begun.

2.- If any judicial proceedings are carried on against the CLIENT that entail
enforcement or attachment.

3.- If the CLIENT ceases to protest acceptances or if default occurs on its
part of any type of payment obligation with third parties.

4.- If, for any reason, the CLIENT ceases to carry on its business, resolves
dissolution, liquidation or closure of the greater part of its establishments.

The CLIENT agrees to notify the FACTOR immediately of the occurrence of any of
the situations listed above.

In the above cases, the FACTOR shall retain ownership of the credits assigned
and it shall take possession of the amount of such credits as have been subject
to advance payment to the CLIENT in the terms provided in clause three hereof. 
It shall likewise take possession of the remaining credits, as far as they
extend, to cover interest, commission and other debts that may be payable by
the debtor. The FACTOR shall deliver the surplus to the person legally
authorised to receive it. Without prejudice to  



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the provisions above, the FACTOR may choose to demand immediate reimbursement of
the amounts that it may have advanced to the CLIENT and withdraw, when it has
been reimbursed, the assigned credits.

B).-Termination due to default by the CLIENT and universal succession in the
CLIENT's company:

In the event of default by the CLIENT of any of the obligations established
herein, or in the case of universal succession in the CLIENT's company
resulting from operations of merger sale, absorption, concentration or
spin-off, the FACTOR shall have the same right to premature termination of this
agreement and may choose to withdraw the assigned credits and demand from the
CLIENT the immediate reimbursement of any amounts that it may have advanced on
account of such credits.

TWELVE.-SUNDRY

1.-Notices and intimations:

All notices (including notification of change of domicile) that must be made
between the parties, unless specifically stated otherwise herein, shall be made
by registered mail with acknowledgement of receipt, telegram with
acknowledgement of receipt or telex, or in cases of urgency, fax, although in
this latter case the notice must be confirmed in writing within the following
five calendar days.

For the purposes hereof, the parties state that the respective domiciles given
for them in this agreement are their valid domiciles for all pertinent notices,
intimations and formalities.

2.-Working days:

For the purposes hereof, days on which the Madrid banks are open and working
normally, excluding Saturdays, shall be considered as working days.

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3.-Delivery of a brochure and delivery of the agreement:

The FACTOR delivers to the CLIENT in this act, who states that it has received
it, its brochures of tariffs for commissions and costs to be shifted that are
applicable to this operation, and an original copy of this agreement.

4.-Subrogation and transfer:

The FACTOR may subrogate any third party in its legal position in this
agreement, and must inform the CLIENT in writing of the said subrogation.
Likewise, the FACTOR may at any time transfer to a third party the credits
assigned to it by the CLIENT.

THIRTEEN.-GUARANTEE CLAUSE

The following shall be attached to this agreement and shall form an integral
and single part hereof.

1.-The agreement known as the "Escrow Agreement", signed on May 7, 1996, an
original copy of which is attached hereto, whereby Nextar Pharmaceuticals Inc.
has agreed with Norwest Bank Colorado, National Association, to deposit in
favour of the FACTOR, and at its request, the amount corresponding to
U.S. $2,010,000 to meet the payment of any amounts that the CLIENT may owe
to the FACTOR.

Nevertheless, by virtue of this clause, the FACTOR has agreed with the CLIENT
that it shall previously demand the amount owed to it from Nextar
Pharmaceuticals Inc. and if, within the maximum term of 30 calendar days,
Nextar Pharmaceuticals Inc. has not paid the said amount, it shall withdraw the
amount deposited in its favour by virtue of the "Escrow Agreement".

When the FACTOR has collected the full amount owed to it, it shall notify
Norwest Bank Colorado so that, as appropriate, it may place at the disposal of
Nextar Pharmaceuticals Inc. the amounts that may continue in deposit.





                                       17

<PAGE>   18
2. The document known as the "Comfort Letter" or "letter of intent" signed by
Nextar Pharmaceuticals Inc. in May 1996, an original copy of which is
attached hereto.



FOURTEEN.-JURISDICTION


The parties hereto, for such matters and disputes as may arise in connection
herewith, and for the exercise of actions other than those pertaining to
enforcement proceedings, expressly renounce any other forum to which they may
have a right, and submit to the jurisdiction and competence of the courts of
Madrid.




                   PARTICULAR CONDITIONS OF THIS AGREEMENT


1) Nominal interest rate at which the advance payments are granted: MIBOR AT
NINETY DAYS (90) PLUS A DIFFERENTIAL OF ONE PER CENT (1%). THIS INTEREST RATE
IS FIXED ON THE DATE WHEN THIS AGREEMENT IS SIGNED, TAKING AS A REFERENCE RATE
THE MIBOR, MAXIMUM RATE, PUBLISHED ON THE DAY OF SIGNING, FOR THE SAME TERM,
OR, IN ITS ABSENCE, THE LAST RATE PUBLISHED.

THIS INTEREST RATE SHALL BE REVIEWED ON THE FIRST WORKING DAY OF EACH CALENDAR
QUARTER.

AS A RESULT, FOR THE FIRST PERIOD IN FORCE OF THE AGREEMENT. THE INTEREST RATE
IS ESTABLISHED AT EIGHT AND FIFTY FIVE HUNDRED PERCENT (8.55%) AND SUCH IS
AGREED BY THE PARTIES.

For the purposes of information and in fulfilment of the provisions contained
in Circular of the Bank of Spain 8/1990, of September 7, the ANNUAL EQUIVALENCE
RATE ("Tasa Anual Equivalente" - TAE) for this operation is 



                                      18
<PAGE>   19
eight and eighty nine hundred percent (8.89%), in accordance with the formula
for obtaining such rate, calculated pursuant to that established in the said
circular, Official State Gazette of September 20, 1990, or in the provisions in
force at any given time.

2) Documents that should be attached to each invoice copy: ORIGINAL COPY OF THE
INVOICE ISSUED IN ACCORDANCE WITH THE PROVISIONS CONTAINED IN POINTS 1 AND 2 OF
CLAUSE TWO.

3) Commission referred to in point number 1 of clause six: (a) one percent
(1%). (b) ONE POINT FIVE PERCENT (1.5%).

4) Maximum amounts referred to in section 3, paragraph one of clause three:

FIVE HUNDRED MILLION PESETAS (500,000,000 PTS)

5) The CLIENT's current or credit account for domiciling all payments, to which
clause nine, point 1 refers:

BANCO SANTANDER
Branch: 137
Account number: 15.282
Town or city: Madrid

6) Percentage of the advance payment referred to in paragraph one of point four
of clause three: EIGHTY PER CENT (80%)


The persons who are appointed to represent the parties, as appropriate, read
the above, confirm the consent granted and sign this agreement in two
counterparts, to a sole effect, the certifying Broker bears witness to the
identity and legal status of the parties hereto and the legitimacy of their
signatures.

SANTANDER DE FACTORING, S.A.                     NEXSTAR FARMACEUTICA, S.A.
ENTIDAD DE FINANCIACION-FACTORING
                                                 P.P. /s/ Mercedes Garcia Bravo
P.P. /s/ SIGNATURE ILLEGIBLE


                                      19
<PAGE>   20
COMPLEMENTARY DOCUMENT TO THE DE FACTORING CONTRACT ENTER BETWEEN NEXSTAR
PHARMACEUTICAL S.A. AND SANTANDER DE FACTORING S.A. 
DATED 21 OF MAY 1996

Madrid February 25, 1997

                                    PRESENT

In the name of SANTANDER DE FACTORING, S.A. F.F.C. (from here on referred as
FACTOR) represented by Mr. Alfonso Madurga and Mr. Javier Blanco attorney to
Banco de Santander and the company according to Power of Attorney issued to the
name of Banco de Santander in the presence of the Notary of the College of
Madrid Mr. Roberto Parejo Gamir, dated May 19, 1987 with protocol number 1,192
register in the civil/commercial registry of Madrid.

And for the other part, NEXSTAR FARMACEUTICA, S.A. (from here on named THE
CLIENT) Represented by Mrs. Mercedes Garcia Bravo legal representative by the
power of attorney conferred to her favor by the society in the presence of the
Notary Mr. Jose Maria Alvarez Vega, dated December 30, 1993 with protocol
number 3,367 in the commercial registry of Madrid.

Both parties recognize legal capacity to get in Contract with common agreement. 

                                   EXPRESSED

1. That dated May 21, 1996 the entities granting the present document
formalized a contract of factoring in the presence of the Agent, Commercial
College Member Mr. Carlos J. Torres Diz.

2. That the entities here represented have come to the agreement make some
modifications to the conditions before established in the factoring contract to
the effect of 

                                     AGREED

FIRST  To modify the condition fourth of the main contract increasing by two
hundred and fifty million pesetas the maximum amount of advances to which
number three refers to on the third stipulation of the contract.

To this effect the Factor can advance the Client up to 80% of the total amount
of credits granted considering that the total amount of advances can never
exceed the amount of seven hundred and fifty million pesetas (750,000,000 PTS)

SECOND  To ratify the complete validity of the rest of the stipulations of the
main contract to the extend that they are not modified by this document which is
part of the same.

After we read this document in the presence of the individuals that are
representatives of the parties, and expressing their approval and consent, sign
in duplicate this document giving faith of the same in the presence of the
Agent and in the capacity of the representatives and their legal signatures.

SANTANDER DE FACTORING, S.A.
p.p. /s/ Signature illegible
NEXSTAR FARMACEUTICA, S.A.
p.p. /s/ Mercedes Garcia Bravo



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