Properties of topically applied organogels: rheology and in vitro drug release

Interest in organogels has increased in a wide variety of fields including chemistry, biotechnology and pharmaceutics. In order to understand the properties and behaviors of different organogels as topical or transdermal drug delivery vehicles, we studied the rheological and in vitro release properties of different organogels formulations. Methods: Amphiphilogels, PC/Span 60/soybean oil organogel, lecithin organogel, Pluronic lecithin organogel and carbopol hydrogel were prepared. The rheological properties of the gels was measured using rheometer with a cone-plate configuration under oscillation mode, and in vitro drug release tests were performed by Franz cell method with piroxicam as the model drug. Results: Amphiphilogels, Pluronic lecithin organogel and carbopol hydrogel exhibited typical characteristic of gels (low phase angles), while PC/Span 60/soybean oil organogel and lecithin organogel were viscoelastic fluids with high phase angles. All these gels showed shear-thinning effect, which was the expected property of topical semisolids. The in vitro drug release results showed that Pluronic lecithin organogel exhibited the highest drug release rate among the gels studied, and the release percent was 81.56%±3.09% at 48 h; While PC/Span 60/soybean oil organogel and carbopol hydrogel exhibited the lowest drug release rates. Conclusions: Although the rheological and in vitro release properties indicated the organogels are potential drug carriers for topical or transdermal application, systematic studies are needed to be performed to choose the suitable organogel matrices for individual active drugs.

Keywords: Organogels Rheology In vitro drug release