Development and in vivo evaluation of baicalin-loaded W/O nanoemulsion for lymphatic absorption

Background: Lymphatic formations that effectively eradicate the virus in the lymphatic system will be therapeutically advantagous in hepatitis B virus (HBV) infection. Lipid-based formulation is often used to deliver drug via the lymphatic system. Baicalin nanoemulsion may be a promising drug delivery system for improved treatment of HBV infection. Objective: This study aimed to prepare, characterize, and evaluate a lipid-based nanoemulsion containing baicalin for lymphatic system absorption. Method: The presence of a nanoemulsion region was studied by pseudoternary phase diagrams. The physicochemical properties of a baicalin-loaded nanoemulsion were investigated. The oral bioavailability of the baicalin-loaded nanoemulsion was compared to that of a baicalin suspension. A chylomicron flow blocking model was used to examine the extent of lymphatic uptake. The lymph node distribution of baicalin was measured to investigate the lymphatic transport ability of the nanoemulsion compared to the suspension. Results: Compared to the baicalin suspension, the AUC_0-t and C_max values of the baicalin nanoemulsion were increased by 10.5-fold and 3.12-fold, respectively. Compared with the saline-treated rats that were orally administered the baicalin nanoemulsion, the AUC_0-t and C_max values of the nanoemulsion for the rats pretreated with cycloheximide were reduced from 23.076 ± 1.244 mg/L h to 9.236 ± 0.940 mg/L h and from 3.010 ± 0.119 mg/L to 1.567 ± 0.220 mg/L, respectively. In comparing baicalin in W/O nanoemulsion with suspension, the C_max value was found to be 11.5-fold higher in the lymph nodes of the rats treated with the nanoemulsion. Conclusion: The results indicated that a baicalin-loaded W/O nanoemulsion may be a promising drug delivery system for the treatment of chronic hepatitis B.