Pharmacokinetics of oxatomide given percutaneously to healthy volunteers

The percutaneous absorption of oxatomide gei at 5 per cent concentration was studied after single and repeated administration (85 mg b.i.d.) in six male and six female healthy volunteers, aged 25·7 ± 0·8 years (mean ± SEM) weighing 64·4 ± 4·5 kg and the results compared with those obtained following a single oral dose (30 mg). The measurement of oxatomide was by means of a new sensitive and specific HPLC assay with limits of detection of 0·2 ng ml −1 in plasma and 1·0 ng ml −1 in urine. Poor percutaneous absorption was confirmed by the peak plasma concentrations which were 5·03 ± 0·79 ng ml −1 following application of the gel for 7 days and 10·08 ± 1·29 ng ml −1 following oral administration; the corresponding amounts of unchanged oxatomide recovered from 24 h urine collections were 1·42 ± 0·39 μg and 3·93 ± 0·92 μg.