SOLUBILITY EVALUATIONS OF OSIMERTINIB MESYLATE IN PHYSIOLOGICAL BUFFERS

Limited water solubility of drugs is a prevailing problem to efficient drug delivery as a huge proportion of available drugs are poorly water soluble. Poorly soluble drugs suffer with low or incomplete oral absorptions leading to low or variable bioavalibilities. Osimertinib mesylate is a novel anticancer drug for the treatment of lung cancer. It is reported to have low absorption and exposure at therapeutic doses of 80 mg which could be due to low solubility in gastrointestinal tract. It is important to evaluate pH solubility profile of the drug over the gastrointestinal pH range in order to find the most suitable region of solubility and absorption. In this study, we are reporting saturated solubility of Osimertinib mesylate in different media with specific pH conditions including different physiological buffers such as simulated gastric fluid, simulated intestinal fluid, phosphate buffer saline. Solubility study was done by classical shake flask method and samples were analyzed by double beam UV spectrophotometer in triplicate. It was found to be very slightly soluble in water with an approximate value of 924 ± 6.06 µg/ml. Of all the tested buffer media, simulated gastric fluid pH 1.2, exhibited maximum solubility, which was approximately 2.3 folds of the solubility exhibited in distilled water. Solubility data over different pH conditions were statistically evaluated using one way ANOVA and post hoc Tukey test for valid conclusions. All media had significant effect on the solubility of the drug except sodium phosphate buffer, pH 3.2 and Acetate buffer pH 5.5 with respect to distilled water. Keywords: Osimertinib mesylate, absorption, Solubility, physiological buffers.