ABSTRACT
Objective To investigate the effects of different penetration enhancers on percutaneous absorption of Xiaoyan Runma mucilage in vitro, and to improve the curative efficacy of this mucilages through selection of the effective penetration enhancers. Methods Xiaoyan Runma mucilage was prepared with different penetration enhancers. An intelligent permeability instrument was used for in vitro percutaneous absorption test of rats , with isolated mice abdomen skin serving as in vitro transdermal barrier and saline isotonic solution as receptor fluid. Then the contents of lidocaine hydrochloride in receptors were determined by HPLC.The accumulative transit dose (Q) and percutaneous permeability (J) within 12 h were calculated and compared with those of mucilage without any enhancer. Results With Q value serving as an index, different enhancers had different promote permeation effects on Xiaoyan Runma mucilage, and the effects in descending order were as follows:4% azone [(222.75±3.4) μg?(cm2)-1]>2% azone[(207.42±5.1) μg?(cm2)-1]>3% menthol [(183.38±4.9) μg?(cm2)-1]>5%menthol [(160.82±5.4) μg?(cm2)-1]>2% azone+3% menthol [(151.25±5.5) μg?(cm2)-1]>2% azone+5% isopropyl myristate [(127.26±7.1) μg?(cm2)-1]>2% oleic acid [(125.16±6.5) μg?(cm2)-1]>no enhancer [(109.82±8.2)μg?(cm2)-1].4% azone was the best penetration enhancer for the mucilage delivery in vitro, with Q and J value as [(222.75± 3.4)μg?( cm2 )-1 ] and 19. 896 μg?( cm2 )-1?h-1 , respectively, which was 2. 08 times those of mucilages without any enhancer. Conclusion Being as a transdermal absorption enhancer of Xiaoyan Runma mucilage, 4% azone has the best effect. This study can provide the optimal formulation for transdermal delivery system of Xiaoyan Runma mucilage.
ABSTRACT
The aim of this study is to prepare cationic biodegradable dextran microspheres loaded with tetanus toxoid (TT) and to investigate the mechanism of protein loading. Positively charged microspheres were prepared by polymerization of hydroxylethyl methacrylate derivatized dextran (dex-HEMA) and dimethyl aminoethyl methacrylate (DMAEMA) in an aqueous two-phase system. The loading of the microspheres with TT was based on electrostatic attraction. The net positive surface charge increased with increasing amounts of DMAEMA. Confocal images showed fluorescein isothiocyanate labeled bovine serum albumin (FITC-BSA) could penetrate into cationic dextran microspheres but not natural dextran microspheres. TT loading efficiency by post-loading was higher compared with by pre-loading. Even though TT is incorporated in the hydrogel network based on electrostatic interaction, still a controlled release can be achieved by varying the initial network density of the microspheres.