Prescription Optimization and Oral Bioavailability Study of Salvianolic Acid Extracts W/O/W Multiple Emulsion

The purpose of this study is to develop a new method of preparing salvianolic acid extracts (SAE) water-in-oil-in-water (W/O/W) multiple emulsion (ME). SAE injection is used in the treatment of brain infarct and promotion of blood circulation in China. However, the injection is not convenient, and the oral preparation has poor bioavailability. Hence, a new preparation that is convenient and stable with good biological availability is required. SAE ME was prepared by two-step emulsification method. Combined with single-factor investigation and orthogonal test, the embedding rate and centrifugal retention rate were taken as the comprehensive indexes to optimize the formulation of SAE ME. The ME size was tested by laser particle size analyzer. The pharmacokinetic studies were conducted in Sprague-Dawley rats with HPLC-MS/MS method. The blood coagulation and hemorheology tests were conducted to assess the effect of preparation in rats. The best preparation technique for SAE ME is by the use of trospium chloride; SAE represent 12% of water in the phase, lipophilic emulsifier hydrophilic lipophilic balance value=4.3, lipophilic emulsifier is 20% of the oil phase. The median diameter of particle is (0.608±0.05) µm and the C_max of ME is 3-fold higher compared to C_max of free drug. The oral biavailability of ME is 26.71-fold higher than that of free drug with good effect on blood circulation. SAE ME is stable hence, improves the biological availability and slows down drug release.