[Preparation of Huoluo Xiaoling gel plaster and its transdermal penetration in vitro]

Huoluo Xiaoling Dan is a classical prescription commonly used for blood circulation and pain relief in clinic with obvious effects. To make it directly treat lesion and improve the effect, this research optimized the preparation process of Huoluo Xiaoling gel paste and further evaluated its in vitro transdermal absorption performance, so as to provide a scientific basis for its development and utilization. Using primary viscosity, holding viscosity, and sensory score as evaluation indexes, the matrix amount of gel paste was determined by the single factor test and Box-Behnken response surface method. The ultra-performance liquid chromatography(UPLC) method was established to determine the content of eight active ingredients, including Danshensu, ferulic acid, salvianolic acid B, salvianolic acid A, ligustilide, tanshinone Ⅱ_A, 11-keto-β-boswellic(KBA), and 3-acetyl-11-keto-β-boswellic acid(AKBA). A mo-dified Franz diffusion cell method was used to evaluate and compare the absorption properties of the gel paste without volatile oil and with volatile oil microemulsion. The results showed that the optimal prescription for Huoluo Xiaoling gel paste matrix was NP700(1.35 g), glycerol(7.00 g), micropowder silica gel(1.25 g), sodium carboxymethyl cellulose(0.20 g), tartaric acid(0.06 g), and glyceryl aluminum(0.04 g). The mass fractions of eight active ingredients in the paste were successively 0.48, 0.014, 0.95, 0.39, 0.57, 0.055, 0.35, and 0.97 mg·g~(-1). The results of the in vitro transdermal absorption test showed that the addition of the volatile oil or the volatile oil microemulsion promoted the transdermal absorption of the active ingredients, and the law of drug penetration conformed to the zero equation or the Higuchi equation. The gel paste prepared by the optimal prescription has good appearance and adhesion, with no residue, and has the characteristics of skeletal slow-release preparation, which is easy to reduce the number of administration, la-ying a foundation for the development of new external dosage forms of Huoluo Xiaoling Dan.