Physico-chemical profiling is a fundamental tool at the early stage of drug discovery in screening drug-like candidates. Complex physico-chemical profiling, including molecular properties such as solubility, ionization, lipophilicity and permeability, has been found to be of predictive power in ADME (absorption, distribution, metabolism, elimination). In the present thesis work, the physico-chemical properties of centrally acting compounds were investigated. We determined the protonation constants (K), the partition coeffitient in octanol/water (Poct) and cyclohexane/water (Pch) systems of antidepressive sertraline and 15 antipsychotic piperidine and piperazine derivatives and calculated the delta logP (logPoct-logPch) values of the molecules. Due to the poor water solubility of the compounds potentiometry using the "co-solvent" technique was applied for the determination of the protonation constants. The logP values were measured by the dual-phase potentiometric titration in octanol/water system and the traditional shake-flask method was used in cyclohexane/water system. Highly precise physico-chemical data were obtained by these validated methods. The relationship between the structure of the molecules and the physico-chemical data was investigated. The pharmacokinetic properties of the compounds were predicted by the physico-chemical parameters. Linear relationship has been found between the brain penetration characterized by the logBB values and the delta logP values. The validity of the equation was controlled by the delta logP and the logBB values of sertraline.
Chemistry, Physical Pharmaceutical Preparations