Modulated release of triterpenic compounds from a O/W/O multiple emulsion formulated with dimethicones: infrared spectrophotometric and differential calorimetric approaches.

From the use of silicones within O/W/O multiple emulsions, we can expect, two principal advantages: (1) the silicones with the lowest molecular weight decrease the oily touch; (2) due to the large range of viscosity, this excipient should influence the skin distribution of actives after topical application. The purpose of our work is to highlight these advantages. Multiple emulsions were formulated with several dimethicones and with drug model. Firstly, the effects of different dimethicones incorporated within multiple emulsions were studied, through in vitro penetration results. Secondly, we investigated the residual film on the skin by Differential Scanning Calorimetry (DSC) and by Fourier Transform Infrared (FTIR) to determine its structure. Correlations were established between the silicone structure and the distribution of drugs in different skin levels or between the silicone structure and the percutaneous penetration. The incorporation of silicones within O/W/O multiple emulsions seems to be an efficient means of modulating the penetration and the distribution of drugs in the skin.

[Not Available]. / Identification et dosage des sels biliaires et de leurs derives conjugues en chromatographie liquide.

Detection and determination of bile acids and their glycine- and taurine-conjugated derivatives are realized by reversed-phase liquid chromatography either directly or after ion-pair formation. Operating conditions and the relation between capacity factors and structure are investigated. The determination of bile acids extracted from biological samples is possible by these techniques.