Preparation And Characterization Of Submicroemulsions Of Extract Of Chinese Allium Fistulosum L. And Their Mucosal Absorption

The submicroemulsions of extract of Chinese Allium fistulosum L.were prepared and the pharmacodynamic effects on the rats with acute myocardial ischemia were studied. Tanshinone IIA as a model drug was incorporated into submicroemulsions and their mucosal absorption experiments were performed to evaluate the buccal delivery of Tanshinone IIA using submicroemulsions. The main results are as follows:(1) The extract of Chinese Allium fistulosum L. (ECAF) was loaded into the various submicroemulsions. The high-pressure homogenization and ultrasonic method were used to prepare ECAF-loaded submicroemulsions and the optimum process was obtained. The submicroemulsion prepared by high-pressure homogenization had good stability. The average diameter of submicroemulsion was 162.8 nm and its polydispersity index (PDI) was 0.156. (2) Poloxamer 407 as a in situ gel matrix was used to construct submicroemulsion-based in situ gel. When the contents of Poloxamer 407 were 14% and 14.5% in gel, their phase transfer temperature was 37.1±0.3℃and 32.5±0.4℃, respectively. It implies that it is possible for submicroemulsion-based in situ gel to form high viscous gel in the oral cavity. (3) The pharmacodynamic effects of ECAF-loaded submicroemulsions and ECAF oily solution on rats with acute myocardial ischemia were compared. The results showed that ECAF-loaded submicroemulsions led to a rapid pharmacodynamic effect in 5 min, but ECAF oily solution only showed similar effect after 10 or 15 min. There were no significant differences between groups on the value of S-T segment and both had similar pharmacodynamic effect. (4) Tanshinone IIA as a model drug was also incorporated into submicroemulsions using high-pressure homogenization. The mucosal absorption experiments were performed to evaluate the buccal delivery of Tanshinone IIA from submicroemulsions and oil solutions, respectively. The results showed that the submicroemulsions could penetrate through mucous membrane in 15 min. The accumulative amount of Tanshinone IIA from submicroemulsions was 10.8μg in 3.0 cm2 area. The oily solution could only penetrate through mucous membrane after 120 min and the accumulative amounts of Tanshinone IIA from solution were 2.44μg in 3.0 cm2 area. The submicroemulsion has a powerful ability to enhance the buccal delivery of lipophilic drugs and can lead to a high permeation rate with short time lag.