Preparation of Silymarin Self-Microemulsifying Capsules and Its Pharmacokinetic Study in Rats

OBJECTIVE To develop the formulation of silymarin self-microemulsifying capsules and study its pharmacokinetics in rats.METHODS The formulation was screened by investigating solubility of silymarin in different mediums and constructing pseudo-ternary phase diagram.The dissolution profile and the morphology of microemulsion after emulsification were determined.The silybrin concentrations in rat plasma were determined by RP-HPLC after oral administration of silymarin self-microemulsifying capsules and raw material.The pharmacokinetic parameters were calculated by software program DAS ver1.0.RESULTS The formulation consisted of octyl and decyl glycerate,cremophor RH40 and transcutol P.The average droplet size was 18.8 nm after dilution.A more than 80% dissolution profile was obtained in 10 min.Pharmacokinetic parameters of the formulation and raw material were as follows:tmax(1.0±0.00) and(1.80±0.45)h;ρmax(14.62±2.42) and(5.75±1.23) mg·L-1;AUC(83.60±11.03) and(36.00±5.90) mg·h·L-1;respectively.CONCLUSION The formulation of silymarin self-microemulsifying drug capsules can increase drug dissolution in vitro and absorption in vivo significantly.