Transcutaneous absorption of naproxen gel.

The kinetics of naproxen was studied in healthy volunteers after cutaneous application of gels containing 5 and 10% of the drug. Bioavailability was estimated from serum concentration and cumulative urinary metabolite excretion data, both determined up to 96 hours after drug administration. The mean bioavailability after the 10% gel was 1.1% (serum data) and 1.0% (urine data), and after the 5% gel it was 2.1% (serum data) and 1.8% (urine data). Despite the small amount of naproxen absorbed, a potential pharmacological effect, due to cutaneous accumulation of the drug following topical administration, may be suggested from the course of the serum concentration-time curves.