Hyaluronic acid based nanocrystals hydrogels for enhanced topical delivery of drug: A case study.

The objective of this study is to use a carbohydrate polymer hyaluronic acid (HLA) as matrix to design novel transdermal nanogel loading poorly soluble drug nanocrystals. Baicalin nanocrystals (BCA-NC) were prepared by coupling homogenization technology and spray-drying technology. The morphology, the rheological behavior and transdermal permeation studies of HLA based BCA-NC-gel were evaluated. The results demonstrated that the BCA-NC could be successfully prepared in terms of trehalose after spray-drying. The trehalose could prevent the aggregation of BCA-NC during spray-drying. It was discovered that, the BCA-NC-gel with 1% HLA possessed the favorable gelatin capacity and thinning shear rheological property. In vitro transdermal permeation studies of BCA-NC-gel/HLA studies indicated a marked increase in the skin permeation of BCA. And the transdermal flux of BCA-NC-gel with 1% HLA were 20.65-fold higher (p < 0.01) than that of coarse BCA-gel, which could be attributed to particles size reduction of BCA-NC and bioadhesive property of HLA. And the morphology characterization of BCA-NC-gel/HLA demonstrated that BCA-NC could be imprisoned into the gel network of HLA, which might prevent it from aggregation in gel. In conclusion, HLA based nanogel system is a promising carrier for effectively transdermal delivery of poorly soluble drug.