Measurement of the distribution coefficients of several classes of drug using reversed-phase thin-layer...

Using reversed-phase thin-layer chromatography, with octan-1-ol as stationary phase and phosphate buffer (pH 7.4) as mobile phase, the behaviour of different drugs at 37 degrees C was studied. Three classes of drug were examined: beta-adrenoceptor antagonists, non-steroidal anti-inflammatory agents and dihydropyridine calcium antagonists. As well as ranking these compounds in terms of their distribution coefficients, an attempt was also made to assign a quantitative value to each. For the beta-adrenoceptor antagonists this was done by using a series of published values obtained using the shake-flask technique: for the non-steroidal anti-inflammatory agents a series of standard compounds was used. No good calibration data were available for the dihydropyridine calcium antagonists, but approximate values were assigned. The results obtained were compared with other published data and the applicability of the method discussed.