STUDIES ON INTERNAL STRUCTURE OF TABLETS .4. EFFECTS OF WATER-CONTENTON PHYSICAL AND CHEMICAL-STABILITY OF TABLETS CONTAINING AN ANTICANCER DRUG TAT-59

xy]phenyl]-2-(4-isopropyl)phenyl]-l-butenyl]phenyl monophosphate (TAT- 59) is a new drug for the treatment of breast cancer. Physical and che mical stability of a tablet consisting of TAT-59 powder and a few exci pients (Formulated tablet), a tablet consisting of only TAT-59 powder (TAT-59 tablet) and TAT-59 powder itself was evaluated based on water content, tensile strength, porosity, the amount of TAT-59 and its hydr olysis product, DP-TAT-59. The water content of Formulated tablet incr eased with relative humidity (RH), whereas that of TAT-59 tablet and T AT-59 powder scarcely changed. The equilibrium water content of Formul ated tablet was much greater than that of the TAT-59 tablet or TAT-59 powder due to adsorbed moisture by the excipients. The tensile strengt h and porosity of Formulated tablet decreased and increased linearly, respectively, with increasing water content. The degradation rate of T AT-59 decreased in the following order: Formulated tablet]TAT-59 table t]TAT-59 powder. The relationship between equilibrium water content an d degradation rate of the Formulated tablet was determined by the Cars tensen equation, in which the interaction order between the drug and w ater content was 1.9, and the degradation of TAT-59 in Formulated tabl et was related to water content. Thus, it was found that the degradati on of TAT-59 was accelerated by compression and addition of excipients .