Exhibit 10(gg)







                                February 10, 1999



William P. Tew, Ph.D
c/o Chesapeake Biological Laboratories, Inc.
1111 South Paca Street
Baltimore, Maryland   21230

Dear Bill:

                  As you know, Chesapeake Biological Laboratories, Inc. (the
"Corporation") and you entered into a letter agreement dated as of December 22,
1998, amending certain provisions of your then existing employment arrangement
with the Corporation, in an effort to better position the Corporation for future
growth. Since that date, however, further discussions have ensued, and it has
been determined that the December 22, 1998 letter agreement did not fully
reflect the intentions of the parties and that certain additional modifications
to the employment arrangement by and between you and the Corporation are
warranted. Accordingly, the purpose of this letter is to set forth all of the
changes to your employment arrangement which have recently been agreed upon,
including those changes which were intended or embodied in the letter agreement
dated December 22, 1998 and the changes which have been discussed and agreed to
in principle since that date. These changes, modifications and agreements are as
follows:

                  1. Effective January 1, 1999, the Employment Agreement dated
July 1, 1995, by and between you and the Corporation, as amended by a letter
agreement dated November 21, 1996 (the "Employment Agreement"), shall be deemed
to be further amended as follows (all capitalized terms used herein and not
otherwise specifically defined shall have the meanings ascribed thereto in the
Employment Agreement):

                     (i)      Paragraph 4 of the Employment Agreement is amended
                              and restated as follows:

                  At all times during the Employment Term, the Corporation
                  agrees to engage the Employee as Chairman of the Board of
                  Directors of the Corporation and the Employee agrees to
                  perform such services as are customarily rendered by chairmen
                  of the board of directors of publicly held companies
                  comparable to the Corporation and which consider the position
                  of Chairman of the Board as an officer position. In addition,
                  the Employee will perform such other executive services for
                  the Corporation as shall from time to time be reasonably
                  assigned to him by the Board of Directors of the Corporation,
                  consistent with the terms of this Agreement and the stature
                  and position of the Employee. Both the Employee and the
                  Corporation


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William P. Tew, Ph.D
February 10, 1999
Page 18


                  acknowledge that the ability of the Employee to serve as
                  Chairman of the Board of the Corporation is conditioned upon
                  the Employee serving as a member of the Board of Directors of
                  the Corporation; accordingly, at all times during the
                  Employment Term, the Corporation, through its Board of
                  Directors, agrees to nominate the Employee as a member of the
                  Board of Directors of the Corporation, and provided the
                  Employee shall remain a member of the Board of Directors of
                  the Corporation, at all times during the Employment Term the
                  Board of Directors of the Corporation shall designate the
                  Employee as Chairman of the Board of Directors of the
                  Corporation. The failure of the stockholders of the
                  Corporation to elect the Employee as a director of the
                  Corporation when nominated from time to time during the
                  Employment Term (and assuming that the Employee agrees to
                  serve if so elected) will be deemed a material diminution in
                  the title or scope of the Employee's responsibilities within
                  the meaning of Paragraph 1(a)(iii) of this Agreement.

                           (ii) Paragraph 3 of the Employment Agreement shall 
be amended such that the Renewal Term in effect as of the date hereof shall 
continue from the date hereof until December 31, 1999, whereupon the 
Employment Term shall be automatically extended for an indefinite number of 
successive one (1) year Renewal Terms (in lieu of three (3) year Renewal 
Terms as currently provided in the Employment Agreement) thereafter, unless 
and until, not less than one hundred eighty (180) days prior to the last day 
of the Renewal Term ending December 31, 1999 or any successive Renewal Term 
then in effect, the Corporation shall have delivered to you, or you shall 
have delivered to the Corporation, written notice that the term of your 
employment under the Employment Agreement will not be so extended.

                           (iii) Your Base Salary, as provided for under 
Paragraph 5 of the Employment Agreement shall be changed from $170,000 per 
year as currently in effect, to $125,000 per year. All other terms currently 
existing under Paragraph 5 of the Employment Agreement, including those 
regarding the manner in which the Base Salary is to be paid, shall continue 
to apply.

                           (iv) The reference to "the number two (2)" in 
clause (ii) of Paragraph 12(d)(x) of the Employment Agreement shall be 
amended to read "the number one (1)" in lieu of "the number two (2)", such 
that any severance payment becoming due to you under paragraph 12(d)(x) of 
the Employment Agreement will be reduced by one-half of the amount which 
would have been payable prior to this amendment.

                           (v) The definition of "Change in Control of the 
Corporation" as set forth in subparagraph (d) of Paragraph 1 of the Agreement 
shall be modified to include, in addition to the events otherwise described 
therein as constituting the occurrence of a change in control of the 
Corporation, a merger, sale of substantially all of the assets of the 
Corporation, share exchange, consolidation or other business combination (as 
defined in the Maryland General Corporation Law) of the Corporation and any 
other person, entity or group of persons or entities acting in concert, as a 
result of which the Corporation's common stock becomes exchangeable for other 
securities or property or cash.

                  2. In consideration for your agreement to the modifications to
your Employment Agreement


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William P. Tew, Ph.D
February 10, 1999
Page 19


as described herein above, the Corporation agrees to pay you the sum of
$170,000, and to grant to you options under the Corporation's Fourth Incentive
Stock Option Plan, on the following terms and conditions:

                           (i) The sum of $50,000 will be paid to you on January
4, 1999, without condition; and the Company agrees to pay you an additional
$120,000, in two equal installments of $60,000 each, payable on the fifteenth
day of the first calendar month and the fifteenth day of the second calendar
month, respectively, following the fiscal quarter of the Corporation during
which a Qualifying Event (as defined below) occurs.

                           For purposes hereof, a "Qualifying Event" shall 
mean the first to occur of either (a) receipt by the Corporation at any time 
or from time to time hereafter of one or more equity investments or loans of 
new money (but not refinancing of existing loans) or any other infusion of 
capital, whether through the sale of common or preferred stock of the 
Corporation or otherwise, in an amount equal to or exceeding, in the 
aggregate, $3,000,000 or (b) in any fiscal quarter of the Corporation, the 
Corporation shall have gross revenues which exceed $3,200,000; or (c) there 
shall occur any Change in Control of the Corporation, as such term is defined 
in the Employment Agreement.

                           It is expressly acknowledged that your right to 
receive payment of the sums which will become due and owing to you upon the 
occurrence of the Qualifying Event shall not be conditioned upon your 
continued employment or any other continuing relationship with the 
Corporation, but shall be an obligation of the Corporation to you independent 
of your continuing status as an employee, officer or director.

                           (ii) In addition, the Corporation agrees to grant 
to you an incentive stock option under the Corporation's Fourth Incentive 
Stock Option Plan, pursuant to which you will be entitled to purchase up to 
125,000 shares of the Corporation's Class A Common Stock at an exercise price 
equal to the closing "ask" price as quoted on the NASDAQ National Market on 
the date hereof. The option will be evidenced by an option agreement typical 
for options of this type, and will provide that the option shall be for a 
term of ten (10) years and exercisable in whole or in part at any time and 
from time to time during the term thereof.

                  3. It is understood and agreed that, notwithstanding the date
hereof, it is the intention of you and the intention of the Corporation that the
agreements set forth herein be effective as of December 22, 1998. In addition,
it is understood and agreed that this letter shall supercede in its entirety the
letter agreement previously executed and delivered by and between you and the
Corporation, dated December 22, 1998.

                  Provided that the terms set forth above are acceptable to you,
we ask that you execute the enclosed counterpart of this letter, and that you
return one fully executed counterpart to me, whereupon this letter


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William P. Tew, Ph.D
February 10, 1999
Page 20


will constitute a legally binding agreement between you and the Corporation, and
the provisions set forth in Paragraph 1 above will constitute an amendment to
your Employment Agreement. As noted above, this letter agreement will supercede
in its entirety the letter agreement dated as of December 22, 1998.

                                     Very truly yours,

                                     Chesapeake Biological Laboratories, Inc.



                                     By:   /s/ ROBERT J. MELLO
                                        ----------------------------------------
                                        Robert J. Mello
                                        Vice President


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William P. Tew, Ph.D
February 10, 1999
Page 21

        The foregoing terms and conditions are hereby accepted and agreed to by
the undersigned on this 10th day of February, 1999, with an effective date as of
December 22, 1998, as hereinabove provided.




                                         By: /s/ WILLIAM P. TEW, PH.D.
                                            ------------------------------------
                                             William P. Tew, Ph.D.




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