HPLC DETERMINATION OF A NEW MULTIDRUG-RESISTANCE MODULATOR (S9788) EXTRACTED FROM CANCER-CELLS IN-VITRO

S9788 is a novel triazinodiaminopiperidine derivative which reverses t he multidrug resistance of tumour cells to anticancer drugs. In this s tudy, a new HPLC method was developed to determine this compound in P3 88 leukaemia cells. The influence of various parameters (composition a nd pH of the mobile phase, nature of the column) on the separation of S9788 and derivatives was investigated. Using a microsphere C18 column and the optimal mobile phase (acetonitrile-0.4M phosphate buffer cont aining 0.2% triethylamine, 40:60 v/v, pH 6.5) it was possible to separ ate S9788 and seven hypothetical metabolites and derivatives in 15 min . The limits of detection and quantification of S9788 are 75 and 250 p g, respectively. This MDR modulator was extracted from biological medi a by a rapid two-step procedure which removed proteins before direct i njection of the sample. Absolute recoveries ranged from 90 to 100% wit h a mean RSD (%) lower than 5.