Biopharmaceutical characterization of some synthetic purine drugs.

Hydrophilic-lipophilic properties (water solubility, n-octanol/water partition coefficient, transport across membranes) of some mercaptopurines (6-MP, 6-TG, AZA and a new AZA derivative - metazathioprine (MAZA) were determined. MAZA is the most lipophilic compound due to low aqueous solubility and high n-octanol/water partition coefficient. The fluxes from the donor medium into the membrane and from the membrane into the acceptor medium are highest for MAZA as well. The partition coefficients of the other purines decrease in the order: AZA > 6-TG > 6-MP.