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                                                                  Exhibit 10.169

                                SIXTH AMENDMENT

     THIS SIXTH AMENDMENT (this "Amendment") dated as of June 30, 2001, to the
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Loan Agreement referenced below, is by and among Pharmaceutical Product
Development, Inc., a North Carolina corporation (the "Borrower"), the
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Subsidiaries of the Borrower identified on the signature pages hereto (the

"Guarantors") and First Union National Bank (the "Bank").  Terms used herein but
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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
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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.
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     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
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     the Bank hereunder, being initially $50,000,000.

          "Consolidated EBITDA" means, for any period for the Borrower and its
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     subsidiaries on a consolidated basis, the sum of (i) Consolidated Net
     Income, plus (ii) to the extent deducted in determining net income, (A)
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     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
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     subsidiaries on a consolidated basis, the sum of Consolidated EBITDA plus
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     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
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     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
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     is not Subordinated Debt.

          "Consolidated Senior Leverage Ratio" means, as of the last day of each
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     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
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     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
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     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
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     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
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          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-
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          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
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          the Borrower may elect; provided that after the occurrence and during
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          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
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          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
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          Borrower agrees to pay to the Bank a facility fee (the "Facility Fee")
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          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.
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          (a)  Consolidated Total Leverage Ratio. As of the last day of each
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          fiscal quarter, the Consolidated Total Leverage Ratio shall be not
          less than 3.25:1.0.

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

          (c)  Consolidated Fixed Charge Coverage Ratio. As of the last day of
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          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
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          its subsidiaries to, make loans or advances or otherwise make an
          investment in or capital contribution to (collectively, an
          "Investment"), any other Person, except:
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          (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.


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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
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                              Name:  Philippe M. Maitre
                              Title:  Chief Financial Officer

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

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

BANK:                         FIRST UNION NATIONAL BANK

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