Application of calcium thioglycolate to improve transdermal delivery of theophylline in rats.

Abstract

To improve drug penetration through the skin, we studied the effect of calcium thioglycolate (Ca-TGA) on the percutaneous absorption of theophylline in comparison with the promoting effects of dimethylsulfoxide (DMSO) and polyoxyethylenelaurylether (BL-9EX). Plasma theophylline concentrations were determined following dermal application of aminophylline to male rats in vivo. The use of aqueous 4w/v% Ca-TGA gave a plasma concentration about 40 times as high as that of the control. whereas 80v/v% DMSO and 20w/v% BL-9EX gave concentrations about 9 times as high as that of the control at most. To obtain a marked promoting effect with Ca-TGA, a pretreatment time of more than 10 min was needed. When Ca-TGA was removed, the promoting effect gradually disappeared and the control value was reached at 48h. Furthermore, when pretreatments with Ca-TGA and BL-9EX were combined, the transdermal delivery of theophylline was promoted more than by each treatment alone.