Method optimization for determination of permeability and degradation products of valgancyclovir and lamivudine

The types of application of drugs are determined by the drug properties and therapeutic purposes of these drugs. These types of applications are divided into three basic groups as enteral, parenteral and the other types of applications. Orally (enternal) type is the most preferred because of its safety and easier application. The physicochemical properties of drugs, the factors about the phsigological and dosage forms are affected to absorption and bioavailability of orally administered drugs. The reason of low absorption of the drugs which are orally used from gastrointestinal tract, is low bioavailability. Biopharmaceutical Classification System (BCS) is a scientific framework according to the solubility and permeability of drugs put forward by Amidon et al. In this study, lamivudine and valgancyclovir's intestinal permeability were evaluated according to Biopharmaceutical Classification System (BCS). For this purpose reverse phase liquid chromatographic method was used. The stress tests are performed to learn about the forced degradation products in terms of active substances and degradation mechanisms. In the second part of these study, degradation products of lamivudine and valgancyclovir were determined by LC-MS/MS method. For this purpose, the active ingredient stress tests were performed in the acidic, basic, thermal and photolytic conditions. According to m/z values and decomposition products, possible drug degradation mechanisms and decomposition products were estimated.