Ligustrazine-Loaded Stealth Liposomes: Cellular Uptake in Murine Phagocyte Cell Model and Pharmacokinetics in Rats

The objective of the present work involves preparation, characterization, cellular uptake and pharmacokinetics of ligustrazine-loaded stealth liposomes (LTSL). LTSL had an average particle size of 112.2 +/- 2.4 nm with a zeta potential of -21 +/- 1.1 mV, and encapsulation efficiency of 83.5 +/- 2.1%. In vitro release study showed a sustained release of ligustrazine (LT) from LTSL in accordance with the Higuchi equation. Phagocytosis tests showed significant differences between LTSL and LTL (ligustrazine-loaded liposomes) and demonstrated that LTSL could decrease opsonization with serum proteins and uptake with phagocyte cells. Pharmacokinetic test indicated that areas under the plasma level-time curve (AUC) of LTSL was 15-fold higher than that of free LT, half-life of LTSL was prolonged by 7.5 folds than that of free LT. Compare to free LT, clearance (CL) of LTSL was decreased notably. LTSL had longer circulating time in blood with mean residence time (MRT) of 5.286 h compared to free LT. LTSL could be a good formulation of LT for clinical application.