摘要：

It is desirable to minimize skin penetration of some drugs, such as sunscreens and insect repellents. Available in vivo and in vitro data suggest appreciable absorption of some sunscreen agents. The purpose of this study was to investigate the effect of hydroxypropyl- β -cyclodextrin (HPβCD) on the release and permeation of the sunscreen agent 2-hydroxy-4-methoxy benzophenone (oxybenzone). The interaction between oxybenzone and HPβCD was studied in water by phase solubility analysis. The inclusion complex was characterized by thermal analysis and nuclear magnetic resonance spectroscopy. UV transmittance and percent UVA transmittance, as a preliminary measure of sun protection factor (SPF), were determined. In vitro permeation experiments were conducted in Franz-type diffusion cells at 37 °C, using the model membrane poly(dimethyl siloxane) ( PDMS ) and 4% bovine serum albumin in phosphate buffer solution (pH7.4) as the receptor phase. HPβCD caused a marked increase in the aqueous solubility of oxybenzone. Data from the phase solubility experiment indicated the formation of 1:1 oxybenzone-cyclodextrin complex. UV transmittance studies indicated that the presence of HPβCD did not suppress the UV absorbing properties of oxybenzone. The release and membrane permeation of oxybenzone was significantly reduced in the presence of equimolar, 2 times molar and 1, 2 and 4% of HPβCD. It is concluded that HPβCD can reduce the release/membrane diffusion of oxybenzone whilst retaining its efficacy as a sunscreen agent. This formulation strategy may be useful in controlling skin penetration of topically applied sunscreens and other chemicals.

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