The influence of the physicochemical characteristics and pharmacokinetic properties of selected NSAID's on their transdermal absorption

Abstract The purpose of this study was to determine the plasma concentrations of selected NSAIDs after topical gel administration and to determine the influence of the physicochemical characteristics of these drugs on transdermal absorption. Plasma concentrations of the drugs were determined using high performance liquid chromatography. The log  P values obtained from literature for piroxicam, ketoprofen, naproxen, ibuprofen and indomethacin, (1.8, 0.97, 3.22, 3.6 and 3.8, respectively) correlated with the area under the plasma–time curve (AUC) values. The AUC values determined were 527.00 (piroxicam) 269.45 (ketoprofen) 258.65 (naproxen) 243.22 (indomethacin) and 88.09 (ibuprofen) μg/ml per h. It was concluded that the most reliable parameter for transdermal absorption was the lipophilic character of a drug (log  P value). The molecular mass, solubility constraint and percentage unionized moiety can only be used in combination with other properties in the prediction of possible transdermal drug delivery.