Determination by HPLC of ketoprofen in aqueous medium used for in vitro skin permeation studies

A HPLC procedure with UV detection has been developed for quantification of ketoprofen release into receptor solution used as acceptor phase for in vi tro skin permeation studies. The assay involves an extraction of the drug a nd the internal standard into chloroform from acidified aqueous media and a ssay by a reverse phase C18 column. Chromatographic separation was achieved using a mobile phase containing a mixture of acetonitrile and phosphate bu ffer, pH 3.0, pumped at flow rate of 0.8 ml/min. The chromatograms were com pletely free from interfering peaks; relative retention times of internal s tandard and ketoprofen were approximate to4.12 and approximate to7.01 min, respectively. Calibration curves showed good linearity over the concentrati on range (100.0 1000.0 ng/ml) examined. Drug recovery was 97.18% and inter- and intraassay variation coefficients were less than 6%.