AMENDED REVOLVING CREDIT AGREEMENT THIS AMENDED REVOLVING CREDIT AGREEMENT is made as of August 31, 1997 and hereby amends that certain Revolving Credit Agreement dated January 31, 1997 by and between Hydrogel Design Systems, Inc., a Delaware...

  
              AMENDED REVOLVING CREDIT AGREEMENT
                                
  
     
  
     THIS AMENDED REVOLVING CREDIT AGREEMENT is made as of 
  August 31, 1997  and hereby amends that certain Revolving
  Credit Agreement dated January 31, 1997 by and between
  Hydrogel Design Systems, Inc., a Delaware corporation (the
  "Borrower"), and Embryo Development Corporation, a Delaware
  corporation (the "Lender").
  
                          WITTNESETH
                          ----------
                                
  
     WHEREAS, the Borrower and Lender are parties to that
  certain Revolving Credit Agreement dated January 31, 1997;
  and
  
     WHEREAS, the Borrower and Lender desire to amend that
  certain Revolving Credit Agreement to effect the changes
  provided for herein.
  
     NOW, THEREFORE, in consideration of the premises and
  mutual covenants contained herein, the receipt and
  sufficiency of which is hereby acknowledged, the parties
  hereto agree as follows:
     
     1.   Effective as of the date hereof, Section 2.1 is
          hereby amended to read as follows:
  
          "2.1 The Loan Commitment. Subject to the terms and
               --------------------
           conditions of this Agreement, the Lender agrees to
           make revolving credit loans (individually, a
           "Loan" the first such Loan, the "Initial Loan":
           and, collectively, the "Loans") to the Borrower
           from time to time during the Loan Commitment
           Period in an aggregate principal amount at any one
           time outstanding not to exceed $850,000 (the "Loan
           Commitment")."
  
  
     2.   This Amendment shall be governed by and construed
          in accordance with the laws of the State of New
          York, without regard to principles of conflicts of
          law.
  
  
     3.   Except as otherwise specifically set forth herein,
          all of the terms and provisions of the Revolving
          Credit Agreement shall remain in full force and
          effect.
  
  
          IN WITNESS WHEREOF, the parties hereto have caused
       this Amended Revolving Credit Agreement to be duly
       executed and delivered by their proper and duly
       executed and delivered by their proper and duly
       authorized officers as of the day and year first above
       written.
          
          
                         HYDROGEL  DESIGN SYSTEMS, INC.
          
                    
          
                         By:/s/Xxxxxxx Xxxxxxxx
                         Name:Xxxxxxx Xxxxxxxx
                         Title:President
          
                         EMBRYO DEVELOPMENT CORPORATION
          
          
                         
                         By:/s/ Xxxxxxx Xxxxxx
                         Name:Xxxxxxx Xxxxxx
                         Title: Chairman