AIM To prepare bergenin nanostructured lipid carriers,and to investigate their in vivo pharmacokinetics.METHODS The nanostructured lipid carriers were prepared by melting method.With solid lipid type,liquid lipid type,solid-liquid lipid ratio,lipid-drug ratio and poloxamer 188 concentration as influecing factors,encapsulation efficiency,drug loading and particle size as evaluation indices,the formulation was optimized by single factor test,after which the in vitro drug release was investigated,the stability was determined,and crystalline form analysis was performed.Eighteen rats were randomly assigned into three groups and given intragastric administration of the 0.5%CMC-Na suspensions of bergenin,physical mixture and bergenin solid dispersions(60 mg/kg),respectively,after which blood collection was made at 0.25,0.5,1,2,3,4,5,6,8,10,12 h,HPLC was adopted in the plasma concentration determination of bergenin,and main pharmacokinetic parameters were calculated.RESULTS The optimal formulation was determined to be glyceryl behenate as solid lipid,oleic acid as liquid lipid,4 ∶ 1 for solid-liquid lipid ratio,10 ∶ 1 as lipid-drug ratio 2.0%for poloxamer 188 concentration,the average concentration,drug loading,particle size and Zeta potential were(84.16±1.57)%,(7.73±0.27)%and(215.53±18.04)nm and-(37.56±2.03)mV,respectively.The nanostructured lipid carriers demonstrated the accumulative release rate of less than 50%within 240 min in simulated gastric fluid,which was 71.04%within 36 h in simulated intestinal fluid,along with good stability within 12 h in the latter.Bergenin existed in the nanostructured lipid carriers in an amorphous state.Compared with raw medicine and physical mixture,the nanostructured lipid carriers displayed prolonged tmax and t1/2(P<0.01),and increased Cmax,AUC0-t,AUC0-∞(P<0.01),whose relative bioavailability was enhanced to 6.08 times as compared with that of raw medicine.CONCLUSION Nanostructured lipid carriers can improve the stability and oral bioavailability of bergenin.