COMPARATIVE EVALUATION OF DIFFERENT PSEUDOSTATIONARY PHASES FOR THE RETENTION OF BETAMETHASONE AND DERIVATIVES BY ELECTROKINETIC CHROMATOGRAPHY

LUCANGIOLI S.,; TRIPODI V.,; BARBARA C.,; SCIOSCIA S.,; CARDUCCI C.

SANTIAGO, CHILE

Simposio; VII SYMPOSSIUM ON BIOMEDICAL, BIOPHARMACEUTICAL AND INDUSTRIAL APPLICATION OF CAPILLARY ELECTROPHORESIS; 2001

Evaluation of the interaction of drugs with different pseudostationary phases in electrokinetic chromatography (EKC) systems has expanded the interest in studies associated with their biologicaL activity-hydrophobicity reLationship. These systems are considered good alternatives to determine the partition coefficients of the compounds with respect to the traditional and tedious octanoljwater method. The aim of this work was to evaluate the retention behavior of bethamethasone and its 17 or 21 derivatives such as bethamethasone acetate, phosphate, propionate and valerate in different electrokinetic systems. Micellar systems based on different surfactants and biosurfactants such as sodium dodecyl sulfate, bile acids, phosphatidylcholine and conventional or no conventionaL microemulsions were investigated. Optimization of every system was accomplished in order to obtain the best resolution. Retention factors were determined as a measure of the interaction of drugs with the pseudostationary phases at pH 7.5. A comparative study between the log k´values obtained with the log P o/w values were performed in order to estimate their relationship and the suitability of the retention factors obtained as predictors of the biopartitioning.