Physico chemical characterization of a novel anti-cancer agent and its comparison to Taxol(®)

Every year several thousand compounds are screened for their anti-cancer activity by a general test procedure amongst which only few selected move past the in vitro screening process. This may be due to the intrinsic property of the drug substance. Therefore, a complete physicochemical characterization of a New Chemical Entity (NCE) is essential to understand the effect of these properties on the in vitro and possibly in vivo behavior of these compounds. Various physicochemical properties such as dissociation constant, octanol-water partition co-efficient, pH solubility, stability, thermal characterization and membrane permeability were evaluated for a novel tubulin-binding agent JCA112 and were compared to that of Taxol(®). The drug exhibited a pKa value of 10.9, log P value of 2.3, pH dependent solubility, and low artificial membrane permeability. Stability of the drug substance in the in vitro screening media suggested a significant degradation during the 48-hour study duration. The results demonstrate that due to low aqueous solubility, limited membrane permeability and due to insufficient stability of JCA112 in the in vitro screening media, the drug exhibited limited anti-cancer activity. Along with challenging physicochemical characteristics, a generalization of the in vitro testing procedure may also result in loss of important anti-cancer agents. As a result, a complete understanding of the physico-chemical properties of the drug leading to prototype formulation with acceptable physico-chemical properties may be required for successful in vitro screening.