Inclusion complexation of the sunscreen agent 2-ethylhexyl-p-dimethylaminobenzoate with hydroxypropyl-beta-cyclodextrin: effect on photostability.

来自 EBSCO

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摘要：

The interaction between the UV filter, 2-ethylhexyl- p -dimethylaminobenzoate, and unmodified and modified α-, β- or γ-cyclodextrins was studied in water by phase-solubility analysis. Of the cyclodextrins available, only hydroxypropyl-β-cyclodextrin caused a marked increase in the aqueous solubility of 2-ethylhexyl- p -dimethylaminobenzoate. The data from the solubility study indicated the formation of a 1:1 (sunscreen-cyclodextrin) complex. The inclusion of the sunscreen agent into the hydroxypropyl-β-cyclodextrin cavity was confirmed by thermal analysis and by nuclear magnetic resonance spectroscopy. Irradiation-induced degradation of 2-ethylhexyl- p -dimethylaminobenzoate was reduced by complexation with hydroxypropyl-β-cyclodextrin, this effect being more pronounced in solution (the extent of degradation was 25.5% for the complex compared with 54.6% for free 2-ethylhexyl- p -dimethylaminobenzoate) than in the emulsion vehicle (the extent of degradation was 25.1% for the complex compared with 33.4% for free 2-ethylhexyl- p -dimethylaminobenzoate). Although photodegradation of the sunscreen agent is significantly reduced by formation of the inclusion complex it is important to design a suitable vehicle. Inclusion of 2-ethyl-hexyl- p -dimethylaminobenzoate-DMAB into the hydroxypropyl-β-cyclodextrin cavity limits interaction of the UV filter with the skin reducing the side-effects of the formulation.

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关键词：

Cyclodextrins Sunscreening Agents 4-Aminobenzoic Acid padimate O 2-hydroxypropyl beta cyclodextrin 环糊精类防晒剂 4-氨基苯甲酸