Transdermal delivery of glucose through hairless rat skin in vitro: effect of multiple and simple emulsions

Three types of oil–water emulsions (W/O/W, O/W and W/O emulsions) were obtained and evaluated on hairless rat skin biopsies, using Franz diffusion cells. Natural emulsifiers (soybean phospholipids) were used to formulate stable multiple and simple emulsions. The qualitative and quantitative composition of the three emulsions was the same. In order to compare the emulsions that have been prepared with this new utilization of soybean phospholipids as emulsifier for vesicular systems and to achieve the importance of application conditions on the diffusion of glucose, a finite dose in open-cap and an infinite dose with occlusion were evaluated. After 24 h of diffusion, the maximum flux (0.69±0.21 μg/cm 2/h) for a finite dose was obtained with simple O/W emulsion, with a rank order of emulsions identical when compared to an infinite dose application: O/W>W/O/W>W/O.