CANCELLATION OF UCT OPTION AGREEMENT The undersigned, NDA Cinical Trial Services, Inc. ("NDA") and shareholders representing a majority of the outstanding shares of capital stock of NDA, hereby agree, for good and valuable consideration, the receipt...

                      CANCELLATION OF UCT OPTION AGREEMENT


     The undersigned,  NDA Cinical Trial Services, Inc. ("NDA") and shareholders
representing  a majority  of the  outstanding  shares of  capital  stock of NDA,
hereby  agree,  for good and  valuable  consideration,  the  receipt of which is
hereby  acknowledged,  that  the  certain  Option  Agreement  among  NDA and its
shareholders,  Unilabs Cinical Trials, Ltd. and UniHolding Corp. dated September
27, 1995 is hereby cancelled, null and void as of the date hereof.

Dated:    August 26, 1996

                                        NDA CLINICAL TRIAL SERVICES, INC.

                                        By:  /s/ Xxxxxx Xxxxxxxxxxx
                                        Name:    Xxxxxx Xxxxxxxxxxx

                                        POLY VENTURES II

                                        By:  /s/ Xxxxxx Xxxxx
                                        Name:    Xxxxxx Xxxxx

                                        LONG ISLAND VENTURE FUND

                                        By:  /s/ Xxxx Xxxxxx
                                        Name:    Xxxx Xxxxxx


                                        By:  /s/ Xxxxx Xxxxxxx
                                        Name:    Xxxxx Xxxxxxx

                                        By:  /s/ Xxxxxx Xxxxxxxxxxx
                                        Name:    Xxxxxx Xxxxxxxxxxx