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                                                                  Exhibit 10.169
                                 SIXTH AMENDMENT

         THIS SIXTH AMENDMENT (this "Amendment") dated as of June 30, 2001, to
the Loan Agreement referenced below, is by and among Pharmaceutical Product
Development, Inc., a North Carolina corporation (the "Borrower"), the
Subsidiaries of the Borrower identified on the signature pages hereto (the
"Guarantors") and First Union National Bank (the "Bank"). Terms used herein but
not otherwise defined herein shall have the meanings provided to such terms in
the Loan Agreement.

                               W I T N E S S E T H

         WHEREAS, a $50 million credit facility has been established in favor of
the Borrower pursuant to the terms of that Loan Agreement dated as of June 24,
1998 (as amended and modified from time to time, the "Loan Agreement") among the
Borrower, the Guarantors and the Bank;

         WHEREAS, the Borrower has requested certain modifications to Loan
Agreement; and

         WHEREAS, the Bank has agreed to the modifications on the terms and
conditions set forth herein.

         NOW, THEREFORE, IN CONSIDERATION of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.       Amendments.
                  ----------

         1.1      In Section 1.1 of the Loan Agreement, the following
definitions are added or amended to read as follows:

                  "Committed Amount" means the aggregate amount of the
         commitments of the Bank hereunder, being initially $50,000,000.

                  "Consolidated EBITDA" means, for any period for the Borrower
         and its subsidiaries on a consolidated basis, the sum of (i)
         Consolidated Net Income, plus (ii) to the extent deducted in
         determining net income, (A) Consolidated Interest Expense, (B) taxes
         and (C) depreciation and amortization, in each case on a consolidated
         basis determined in accordance with GAAP.

                  "Consolidated EBITDAR" means, for any period for the Borrower
         and its subsidiaries on a consolidated basis, the sum of Consolidated
         EBITDA plus rental and lease expense, in each case on a consolidated
         basis determined in accordance with GAAP

                  "Consolidated Fixed Charge Coverage Ratio" means, as of the
         last day of each fiscal quarter, the ratio of Consolidated EBITDAR for
         the period of four consecutive fiscal quarters ending as of such day to
         Consolidated Fixed Charges for the period of four consecutive fiscal
         quarters ending as of such day.

                  "Consolidated Senior Funded Debt" means Consolidated Funded
         Debt that is not Subordinated Debt.

                  "Consolidated Senior Leverage Ratio" means, as of the last day
         of each fiscal quarter, the ratio of Consolidated Senior Funded Debt on
         such day to Consolidated EBITDA for the period of four consecutive
         fiscal quarters ending as of such day.


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                  "Consolidated Total Leverage Ratio" means, as of the last day
         of each fiscal quarter, the ratio of Consolidated Funded Debt on such
         day to Consolidated EBITDA for the period of four consecutive fiscal
         quarters ending as of such day.

                  "Subordinated Debt" means any indebtedness of the Borrower or
         any of its subsidiaries which by its terms is expressly subordinated in
         right of payment to the prior payment of the obligations of the
         Borrower and the Guarantors under the Credit Documents on terms and
         conditions and evidenced by documentation satisfactory to the Bank.

                  "Termination Date" means June 29, 2002, or such later date as
         to which the Bank may agree in its sole discretion.

         1.2      Clause (a) of Section 2.3 of the Loan Agreement is amended to
read as follows:

                  (a) Loans. Loans outstanding hereunder shall bear interest at
                  a per annum rate equal to (i) for any day that the average
                  amount of outstanding Obligations for such day exceeds an
                  amount equal to fifty percent (50%) of the Committed Amount,
                  the LIBOR Rate plus seven-eighths of one percent (0.875%),
                  (ii) for any day that the average amount of outstanding
                  Obligations for such day is less than an amount equal to fifty
                  percent (50%) of the Committed Amount, the LIBOR Rate plus
                  five-eighths of one percent (0.625%) or (iii) the Prime Rate,
                  as the Borrower may elect; provided that after the occurrence
                  and during the continuance of an Event of Default, the
                  principal and, to the extent permitted by law, interest on the
                  Loan and any other amounts owing hereunder shall bear
                  interest, payable on demand, at a rate equal to the Prime Rate
                  plus two percent (2%). Interest will be payable in arrears on
                  each Interest Payment Date.

         1.3      Clause (a) of Section 2.6 of the Loan Agreement is amended to
read as follows:

                  (a) Facility Fee. In consideration of the commitments
                  hereunder, the Borrower agrees to pay to the Bank a facility
                  fee (the "Facility Fee") equal to fifteen basis points (0.15%)
                  per annum on the average daily unused portion of the Committed
                  Amount for the applicable period. The Facility Fee shall be
                  payable quarterly in arrears on the 15th day following the
                  last day of each calendar quarter for the immediately
                  preceding quarter (or portion thereof) beginning with the
                  first such date to occur after the date hereof.

         1.4      Section 6.5 of the Loan Agreement is amended to read as
follows:

                  6.5      Financial Covenants.
                           -------------------

                  (a)      Consolidated Total Leverage Ratio. As of the last day
                           ---------------------------------
                   of each fiscal quarter, the Consolidated Total
                   Leverage Ratio shall not be greater than 3.25:1.0.

                  (b)      Consolidated Senior Leverage Ratio. As of the last
                           ----------------------------------
                  day of each fiscal quarter, the Consolidated Senior
                  Leverage Ratio shall not be greater than 2.0:1.0.




                  (c)      Consolidated Fixed Charge Coverage Ratio. As of the
                           ----------------------------------------
                  last day of each fiscal quarter, the Consolidated Fixed
                  Charge Coverage Ratio shall be not less than 3.0:1.0.

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         1.5      Section 6.6 of the Loan Agreement is amended to read as
 follows:

                  6.6      [Reserved]

         1.6      Section 6.9 of the Loan Agreement is amended to read as
 follows:

                  6.9 Investments. The Borrower will not, nor will it permit any
                  of its subsidiaries to, make loans or advances or otherwise
                  make an investment in or capital contribution to
                  (collectively, an "Investment"), any other Person, except:

                           (a) cash and cash equivalents and other publicly
                  traded equity and debt instruments reasonably acceptable to
                  the Bank;

                           (b) loans and advances to officers, directors,
                  employees and shareholders not to exceed $2,000,000;

                           (c) Investments in and to Digital Arts & Science in
                  an aggregate principal amount (on a cost basis) not to exceed
                  $1,500,000 at any time;

                           (d) seller financing promissory note from current
                  management of APBI in favor of the Borrower in an aggregate
                  principal amount not to exceed $18,000,000 in connection with
                  the sale of APBI to current management of APBI;

                           (e) cash equity investments in and to
                  ADoctorInYourHouse.com in an aggregate principal amount (on a
                  cost basis) not to exceed $5,000,000 at any time;

                           (f) loans and advances to NeoRx in an aggregate
                  principal amount not to exceed $5,000,000 at any time;

                           (g) capital stock of DNA Sciences, Inc. in an amount
                  (on a cost basis) not to exceed $15,000,000;

                           (h) Investments in and to a Credit Party; and

                           (i) Investments of a nature not contemplated in the
                  foregoing subsections in an amount not to exceed (a)
                  $20,000,000 for any single Investment (or any series of
                  related Investments) and (b) $50,000,000 in the aggregate in
                  any fiscal year.

         2. This Amendment shall be effective upon execution hereof by the
Borrower, the Guarantor and the Bank.

         3. Except as expressly modified hereby, all of the terms and provisions
of the Loan Agreement (including schedules and exhibits thereto) shall remain in
full force and effect.



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         4. The Borrower agree to pay all reasonable costs and expenses of the
Bank in connection with the preparation, execution and delivery of this
Amendment, including without limitation the reasonable fees and expenses of
Moore & Van Allen, PLLC.

         5. This Amendment may be executed in any number of counterparts, each
of which when so executed and delivered shall be deemed an original and it shall
not be necessary in making proof of this Amendment to produce or account for
more than one such counterpart.

         6. This Amendment shall be deemed to be a contract made under, and for
all purposes shall be construed in accordance with, the laws of the State of
North Carolina.

                  [Remainder of Page Intentionally Left Blank]



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         IN WITNESS WHEREOF, each of the parties hereto has caused a counterpart
of this Sixth Amendment to be duly executed and delivered as of the date first
above written.

BORROWER:                           PHARMACEUTICAL PRODUCT DEVELOPMENT, INC.,
                                    a North Carolina corporation

                                    By:   /s/  Philippe M. Maitre
                                       ---------------------------
                                    Name:  Philippe M. Maitre
                                    Title:    Chief Financial Officer

GUARANTORS:                         PPD DEVELOPMENT, LLC,
                                    a Texas limited liability company

                                    By:   /s/  Philippe M. Maitre
                                       ---------------------------
                                    Name:  Philippe M. Maitre
                                    Title:    Vice President

BANK:                               FIRST UNION NATIONAL BANK

                                    By:  /s/   Keith S. Law
                                       ---------------------------
                                    Name:  Keith S. Law
                                    Title:  Vice President


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