[Puerarin-Chuanxiong oil submicron emulsion combining medicine and adjuvant]

Abstract

This study was mainly based on the compatibility of Puerariae Lobatae Radix and Chuanxiong Rhizoma to prepare submicron emulsion and evaluated its physical and pharmaceutical properties. Firstly, pseudo-ternary phase diagrams were drawn by dripping method which took Chuanxiong oil as the oil phase and the area of microemulsion region as the index. On this basis, suitable emulsifier and co-emulsifier were screened for the preparation of Chuanxiong oil submicron emulsion. Then, the formula realizing the largest oil loading was selected. Finally, puerarin substituted part of emulsifier and co-emulsifier to lower their content, so as to form puerarin-Chuanxiong oil submicron emulsion featuring the combination of medicine and adjuvant. Its particle size, zeta potential, centrifugal stability and storage stability were determined, and the in vitro drug release behavior was investigated by dialysis bag method, based on which the quality of the as-prepared submicron emulsion was evaluated comprehensively. The proposed method was proved feasible for the preparation of Chuanxiong oil submicron emulsion, which adopted polyoxyethylene castor oil(EL-40) as the emulsifier and was free from co-emulsifier. The formula of the maximum oil loading was found as Chuanxiong oil∶EL-40∶water 3∶7∶90. Further, puera-rin successfully replaced up to 10% of the emulsifier in submicron emulsion. Eventually, the optimal drug-loading formula was determined as puerarin∶Chuanxiong oil∶EL-40∶water 7∶30∶63∶900. The quality evaluation results of the as-prepared submicron emulsion demonstrated that the average emulsion droplet size was 333.9 nm, the PDI 0.26, and the zeta potential-10.12 mV. The submicron emulsion had a good centrifugal stability and did not present any instable phenomena such as delamination and precipitation during its standing still for 50 days. The evaluation of in vitro drug release behavior indicated that the submicron emulsion was capable of releasing the drug completely. The puerarin-chuanxiong oil submicron emulsion prepared in this study possessed a stable quality and to some extent increased the solubility of puerarin along with a sustained-release effect. This study provided ideas for the clinical application of puerarin.

Keywords: Chuanxiong oil; combination of medicine and adjuvant; puerarin; submicron emulsion.