Enhancing effect of polyoxyethylene alkyl ethers on the skin permeation ofibuprofen

The influence of polyethoxylated non-ionic surfactants on the transport of ibuprofen across rat skin was investigated. The skin permeation of ibuprofe n from a series of 17 polyoxyethylene (POE) alkyl ethers containing 5% ibup rofen was determined using Franz diffusion cells fitted with excised rat sk ins. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were performed for the physicochemical characterizati on of ibuprofen-surfactant interaction. In vitro transdermal flux through e xcised rat skin was found in the decreasing order of POE(5)cetyl/oleyl ethe r (110.24 mug/cm(2)/h) > POE(2)lauryl ether (99.91 mug/cm(2)/h) > POE(2)ole yl ether (67.46 mug/cm(2)/h) >POE(10)stearyl ether (66.19 mug/cm(2)/h). POE (2)oleyl ether showed the longest lag time (2.47 h). The enhancers containi ng the EO chain length of 2-5, HLB value of 7-9 and an alkyl chain length o f C16-C18 were effective promoters of ibuprofen flux. FT-IR and DSC studies to probe the nature of the interaction between the ibuprofen and surfactan t indicated that the hydrogen bonding state of ibuprofen was changed from t he dimeric form to the carbonyl-hydroxyl (C=O-HO) hydrogen bond form in the presence of excess POE alkyl ether. These results indicated that this new system may be used in developing a transdermal formulation with improved sk in permeation of ibuprofen. (C) 2000 Elsevier Science B.V. All rights reser ved.