EIGHTH AMENDMENT TO
                   SECOND AMENDED AND RESTATED LOAN AGREEMENT

         AGREEMENT (this "Agreement"), made as of this 30th day of September,
1997, by and among FLEET BANK-NH, a trust company organized under the laws of
New Hampshire ("Fleet"); MELLON BANK, N.A., a national banking association
("Mellon"); and IGI, INC., a Delaware corporation ("IGI"), IGEN, INC., a
Delaware corporation ("IGEN"), IMMUNOGENETICS, INC., a Delaware corporation
("ImmunoGen"), and BLOOD CELLS, INC., a Delaware corporation ("BCI"). Fleet and
Mellon are hereinafter sometimes individually referred to as a "Lender" and
collectively referred to as the "Lenders", and IGI, IGEN, ImmunoGen and BCI are
hereinafter sometimes individually referred to as a "Borrower" and collectively
referred to as the "Borrowers".

                          W I T N E S S E T H:
                          -------------------

         WHEREAS, the Lenders and the Borrowers are parties to a Second Amended
and Restated Loan Agreement between them dated as of December 13, 1995 (as
amended to date, the "Loan Agreement"), the terms and conditions of which are
hereby incorporated herein by reference; and

         WHEREAS, the Borrowers have requested an increase in amount and
extension of maturity of the Line of Credit Commitment under the Loan Agreement;
and

         WHEREAS, the Lenders are willing to grant such increase and extension
on the terms and conditions contained in this Agreement;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants herein contained, the parties hereby agree as follows:

         1. Definitions.

         Except as otherwise defined herein, all capitalized terms used in this
Agreement have the respective meanings ascribed to them in the Loan Agreement.

         2. Amendment to Line of Credit Commitment.

             (a) Sections 2.02(a) and 2.02(b) of the Loan Agreement are hereby
amended so as to read in full as follows:

             "Section 2.02. Line of Credit Loans.

                (a) Subject at all times to all of the terms and conditions of
this Agreement, the Lenders hereby severally (and not jointly and severally)
agree to extend to the Borrowers



<PAGE>


(jointly and severally) a secured line of credit loan facility, to December 31,
1997 (the "Line of Credit Termination Date"), in an aggregate principal amount
not to exceed, at any time outstanding, Twelve Million ($12,000,000) Dollars
(the "Line of Credit Commitment"). Such line of credit loans are herein
sometimes referred to individually as a "Line of Credit Advance" and
collectively as the "Line of Credit Advances". Subject at all times to all of
the terms and conditions of this Agreement, to the Line of Credit Termination
Date and within the limits of the Line of Credit Commitment, Fleet shall lend
fifty-five (55%) percent and Mellon shall lend forty-five (45%) percent of the
aggregate amount of each Line of Credit Advance and of all Line of Credit
Advances, and the Borrowers (including, without limitation, any one or more of
the now-existing Subsidiaries directly) shall jointly and severally, as to all
Borrowers, borrow, prepay (without penalty, except as otherwise provided in the
Line of Credit Notes) and reborrow under this Section 2.02. Each request for a
Line of Credit Advance by the Lenders shall be made in writing by the Chairman,
the President or the Chief Financial Officer of IGI or other authorized Person
designated by IGI in writing, or by telephonic communication by such officer of
IGI or other designated Person to the Lenders, which shall be confirmed by
written notice to the Lenders to be delivered to the Lenders by the third
Business Day next following the subject request, which notice shall be in
substantially the form of the Borrowing Request Certificate annexed as Exhibit
"J" to the Original Agreement.

                (b) The Borrowers shall jointly and severally pay the Lenders
interest on all Line of Credit Advances at the rate(s) per annum as in effect
from time to time in accordance with the Line of Credit Notes. Such interest
shall be payable monthly in arrears, and shall be computed on the daily unpaid
balance of all Line of Credit Advances made under the Borrowers' revolving
credit loan accounts with the Lenders, based on a three hundred sixty (360) day
year, counting the actual number of days elapsed. In addition, the Borrowers
shall jointly and severally pay to the Lenders, quarterly through the Line of
Credit Termination Date, in arrears, a fee (the "Line of Credit Commitment Fee")
computed by multiplying (i) one-ha1f of one (1/2%) percent, times (ii) the
actual number of days in the subject quarterly period, times (iii) the
difference of (x) $12,000,000 minus (y) the average daily principal amount of
all outstanding Line of Credit Advances to the Borrowers during such quarterly
period, and then dividing such product by three hundred sixty (360). The
Borrowers jointly and severally hereby authorize the Lenders to charge the
Borrowers' line of credit loan accounts for all such interest and Line of Credit
Commitment Fees. The Agent will report to IGI monthly as to the status of such
line of credit loan accounts, and each such report shall be fully binding on all
Borrowers, except to the extent that IGI gives the Lenders written notice of
exceptions

                                       2



<PAGE>


within thirty (30) days after its receipt of such report."

                (b) Subsections (c), (d), (e) and (f) of Section 2.02 of the
Loan Agreement shall remain unchanged, subject to the replacement of the
existing Line of Credit Notes in accordance with paragraph 3 below.

                (c) In order to conform each Lender's adjusted share of the
outstanding Line of Credit Advances in accordance with the amendment set forth
in paragraph 2(a) above, the Agent shall make all necessary reconciliations and
adjustments as promptly as practicable and in any event not later than the next
settlement as between the Lenders, pursuant to Section 9.10 of the Loan
Agreement, in respect of any disbursements or collections in respect of Line of
Credit Advances; and the Lenders shall make any and all required payments
pursuant to such reconciliation in accordance with such Section 9.10 of the Loan
Agreement.

         3. Replacement of Existing Line of Credit Notes.

            The Line of Credit Notes outstanding immediately prior to the
execution and delivery of this Agreement shall be superseded and replaced by new
Line of Credit Notes in substantially the forms attached hereto as Exhibits A-l
and A-2, respectively, and such replacement Line of Credit Notes shall, from and
after the effectiveness of this Agreement, be deemed to be the Fleet Line of
Credit Note and the Mellon Lane of Credit Note, respectively, for all purposes
of the Loan Agreement, Security Documents and other agreements and instruments
under and pursuant to the Loan Agreement.

         4. Representations and Warranties.

            The Borrowers hereby confirm that (a) all representations and
warranties made by the Borrowers in the Loan Agreement are true and correct on
and as of the date hereof, and (b) no Default or Event of Default has occurred
and is continuing on the date hereof.

         5. Conditions Precedent.

            The effectiveness of this Agreement and the amendments to be
effected hereby are expressly subject to (a) the execution and delivery of this
Agreement by the Borrowers and the Lenders, (b) the execution and delivery by
the Borrowers to the respective Lenders of the replacement Notes contemplated by
paragraph 3 above, and (c) the truth and accuracy, at the time of satisfaction
of the conditions set forth in the foregoing paragraphs 5(a) and 5(b), of the
Borrower's representations and warranties contained in paragraph 4 above.

                                       3



<PAGE>


         6. No Novation; Confirmation and Reaffirmation.

            (a) Each of the Borrowers hereby reaffirms all of its
representations and warranties in the Loan Agreement (as amended hereby) and the
Security Documents on and as of the date hereof, as if expressly made on and as
of the date hereof.

            (b) Each of the Borrowers hereby confirms the ongoing validity of
all of the Obligations outstanding on the date hereof (including but not limited
to Obligations under the Notes), and further acknowledges, confirms and agrees
that none of the amendments effected by this Agreement constitutes a novation of
any of the Obligations outstanding on the date hereof or immediately prior to
the effectiveness of this Agreement.

            (c) Each of the Borrowers hereby reaffirms the validity of all of
the liens and security interests heretofore granted to the Agent as collateral
security for the Obligations, and acknowledges that all of such liens and
security interests, and all collateral heretofore pledged as security for the
Obligations, continue to be and remain collateral for the Obligations (whether
heretofore created, now existing and/or hereafter arising) from and after the
effectiveness of this Agreement.

         7. Ongoing Force and Effect.

            Except as and to the extent expressly provided in this Agreement,
all covenants, terms and conditions of the Loan Agreement shall remain unchanged
and in full force and effect. All references to the Loan Agreement contained in
the Notes and the Security Documents shall hereafter mean and refer to the Loan
Agreement as amended by this Agreement, and all references to the Notes
contained in the Loan Agreement and the Security Documents shall hereafter mean
and refer to the Notes as amended and supplemented pursuant to this Agreement.

         8. Miscellaneous.

            (a) The Borrowers will jointly and severally reimburse the Lenders
and the Agent upon demand for all out-of-pocket costs, charges and expenses of
the Lenders and the Agent (including, without limitation, the reasonable fees
and disbursements of counsel to the Lenders and the Agent) in connection with
the preparation, execution and delivery of this Agreement, the replacement Notes
pursuant to paragraph 3 above, any and all further agreements and instruments in
connection herewith, and any amendments, modifications, consents, waivers or
enforcement action in connection herewith.



                                       4


<PAGE>


            (b) This Agreement shall be governed by and construed in accordance
with the laws of the State of New Hampshire (without giving effect to principles
of conflicts of laws).

            (c) Neither this Agreement nor any provision hereof may be waived,
amended or modified except by means of a written agreement signed by the party
to be charged therewith, and then only in the specific instance and for the
specific purpose stated therein.

            (d) This Agreement shall be binding upon and shall inure to the
benefit of the parties hereto and their respective successors and assigns
except that none of the Borrowers shall have any right to assign any of its
rights or obligations hereunder or any interest herein without the prior written
consent of the Lenders.

            (e) Each of the Borrowers hereby consents to the jurisdiction of all
courts (state and federal) sitting in the State of New Hampshire, and of all
courts from which an appeal may be taken from any of such courts, for the
purpose of any suit, action or other proceeding arising out of any of its
obligations hereunder or with respect to the transactions contemplated hereby.
Each of the Borrowers hereby expressly waives any and all objections which it
may have as to venue in any of such courts, and also hereby knowingly WAIVES
TRIAL BY JURY in any such suit, action or other proceeding.

            (f) The paragraph headings in this Agreement are included for
convenience of reference only, and shall not affect the construction or
interpretation of any of the provisions hereof.

            (g) This Agreement may be executed in any number of counterparts,
each of which shall be deemed an original, but all of which shall together
constitute one and the same instrument.

            (h) The parties acknowledge and agree that each of them and
its counsel have reviewed and negotiated the terms and provisions of this
Agreement, and have contributed to its final form; accordingly, any rules of
construction to the effect of construing ambiguities against the drafting party
shall not be employed in the interpretation of this Agreement, which shall be
construed fairly as to all parties hereto and not in favor of or against any
particular party who might generally have been responsible for the preparation
hereof.

            (i) This Agreement is intended for the sole and exclusive benefit of
the parties hereto and their respective

                                       5


<PAGE>


successors and permitted assigns, and no other person or entity shall have any
right to rely on this Agreement or to derive any benefit herefrom absent the
express written consent of the party to be charged with such reliance or
benefit.

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by their duly authorized officers as of the date first set forth above.

                                           FLEET BANK-NH

                                           By: /s/ Marcia LaTorre
                                               ------------------------------
                                                   Vice President
                                           MELLON BANK, N.A.


                                           By: /s/ John R. Gelsinger, Jr.
                                               ------------------------------
                                                   Vice President
                                           IGI, INC.


                                           By: /s/ Kevin J. Bratton
                                               ------------------------------
                                           IGEN, INC.


                                           By: /s/ George P. Warren, Jr.
                                               ------------------------------
                                           IMMUNOGENETICS, INC.

                                           
                                           By: /s/ Kevin J. Bratton
                                               ------------------------------
                                           BLOOD CELLS, INC.


                                           By: /s/ Kevin J. Bratton
                                               ------------------------------


                                       6