OBJECTIVETo compare the pharmacokinetic characteristics of brucine following intravenous administration of liposomes, containing total alkaloids from seed of Strychnos nux-vomica, to rats with different phospholipids composition.

METHODLiposomes containing the total alkaloids were prepared by the method of ammonium sulfate transmembrane gradients and stealth liposome technique. The contents of total alkaloids and brucine in liposomes were determined and compared after free drug being removed. After intravenous administration of total alkaloids solution or liposomes with different composition, plasma samples were drawn at predetermined time points and the concentrations of brucine were determined by a validated method of HPLC. Pharmacokinetic analysis was performed by 3P97 program.

RESULTThe ratios of brucine to total alkaloids in liposomes hardly varied with phospholipids composition. Compared with SPC liposome, AUC of brucine was increased 13.3-fold and apparent volume of distribution was decreased to only 3.6% following intravenous administration of HSPC liposome. In addition, besides that AUC of brucine was slightly increased, most pharmacokinetic parameters were not significantly changed after administration of the novel liposome compared with those of SPC liposome.

CONCLUSIONPhospholipids composition has a significant influence on the pharmacokinetics of brucine after intravenous administration of liposomes containing total alkaloids from seed of S. nux-vomica.