RÉSUMÉ
OBJECTIVE： To prepare puerarin microemulsion with phase Ⅰ metabolic regulation （R-PR-ME） and to study pharmacokinetic characteristics of rats in vivo. METHODS： R-PR-ME and Puerarin microemulsion without metabolic regulation （NR-PR-ME） were prepared by Shah method. Pseudo-ternary phase diagram was used to optimize microemulsion formula using drug loading amount as index. The particle size and PDI of microemulsion were characterized by using a laser particle size analyzer. Rats were used as animal models， and HPLC method was used to determine the blood concentration of puerarin before and 5， 10， 15， 20， 30， 45， 60， 90， 120， 180， 240， 360， 480， 600 min after intragastric administration of R-PR-ME， NR-PR-ME and puerarin suspension （PR-SP） at puerarin dosage of 120 mg/kg. The pharmacokinetic parameters were calculated by using DAS 2.0 software. SPSS 19.0 software was used for statistical analysis. The relative bioavailability of R-PR-ME was calculated with NR-PR-ME as reference preparation. RESULTS： The formula of R-PR-ME included that oleoyl polyoxyl-6 glyserides （oil phase）-polysorbate 20 （emulsifier）-glycerides （co-emulsifier） mass ratio of 2 ∶ 4 ∶ 4； drug-loading amount of 67.50 mg/g， particle size was （22.59±0.53） nm （n＝3） and PDI was 0.182±0.017 （n＝3）. The formula of NR-PR-ME included that soybean oil （oil phase）-polysorbate 80 （emulsifier）- glycerol （co-emulsifier） mass ratio of 1 ∶ 4.5 ∶ 4.5， drug-loading amount of 61.32 mg/g， particle size of （15.45±1.06） nm（n＝3） and PDI of 0.156±0.012 （n＝3）. Pharmacokinetic parameters of R-PR-ME， NR-PR-ME and PR-SP included that AUC0-600 min were （134.187±37.152）， （65.145±18.762） and （49.623±12.143） μg·min/mL； cmax were （1.316±0.306）， （1.082±0.294） and （0.425±0.106） μg/mL； MRT were （155.068±33.204）， （100.264±27.683）， （60.524±14.086） min； t1/2β were （365.880±101.250）， （283.280±80.940）， （80.063±21.189） min （n＝6）， respectively. Compared with PR-SP， AUC0-600 min， cmax， MRT and t1/2β of R-PR-ME and NR-PR-ME were increased significantly （P＜0.05 or P＜0.01）. Compared with NR-PR-ME， AUC0-600 min， MRT and t1/2β of R-PR-ME were more higher （P＜0.05）. The relative bioavailability of of R-PR-ME was 205.98％. CONCLUSIONS： R-PR-ME is prepared successfully with high drug-loading amount， and can significantly increase the bioavailability of puerarin in rats， compared with PR-SP and NR-PR-ME.