A comparison of theoretical methods of calculation of partition coefficients for selected drugs.

Hundred ninety three drugs of different pharmacological activity were studied. Lipophilicity of a drug is one of the parameters, which influence its biological activity. The n-octanol-water partition coefficients were calculated for these compounds by use of different theoretical procedures (AlogPs, IAlogP, miLogP, ClogP, logP(Kowwin), and xlogP). Particular theoretical partition coefficients were compared with experimental n-octanol-water partition coefficients (logP(exp)) for all studied drugs. It was shown that experimental partition coefficients correlate the best with theoretical partition coefficients calculated by use of logP(Kowwin) and AlogPs methods. It was shown that it exists the possibility of the prediction of experimental n-octanol-water partition coefficients on the basis of logP(Kowwin), AlogPs, and ClogP for fifteen drugs (adrenalin, clobazam, 5,5-dimethylbarbituric acid, ethyl nicotinate, fluphenazine, ibuprofen, methyllorazepam, pimozide, prednisolone, promethazine, spironolactone, surital, theophylline, triamterene, and trimethoprim).