Studies On The PVP-coated β-elemene Liposomes

β-elemene is a sesquiterpene ingredient extracted from one of the traditional Chinese herbal medicine Curcuma wenyujin Chen et C. Ling. Recent studies have shown that β-elemene possesses specific cytotoxicity. As a broad-spectrum anti-tumor agent, β-elemene exhibits pharmacological effects including anti-tumor, antibacterial, antivirus, improving immunity, inhibiting platelet aggregation and improving microcirculation, etc. PVP (pyrrolidone) is one kind of amphipathic macromolecule material, which could be used as protectant in liposomes. PVP has the potential of prolonging resident time in vivo. PVP-coated β-elemene liposomes were prepared to improve oral bio-availability.To investigate the envelop efficiency of β-elemene liposomes coated by pyrrolidone, GC analysis method was developed. Linear equation was y =1.384 p-0.0047 (r =1.000) in the concentration between 0.1250 and 8.018 g . L^-1. Minicolumn centrifugation method was selected to detect envelop efficiency after comparing of others. Precision and accuracy answered for the requirement.The orthogonal test showed that the optimal composition contained 1% PVP-k30, 0.5%β-elemene, 6% phospholipid and 1% cholesterol. Particle size and envelop efficiency was satisfied with 30 r . min^-1 agitating on 50 ℃.Diameter of PVP-coated β-elemene liposome was 162nm on average compared that the β-elemene liposome was 147 nm. Result of TEM confirmed the envelop structure.Stability of β-elemene crude drug and preparation was investigated separately. β-elemene crude drug was steady in all four organic solvents, preparation was steady in acceleration test on 4℃. While in condition of illumination and high temperature β-elemene liposomes degraded apparently. Therefore PVP-coated β-elemene liposomes should be conserved in low temperature and avoid of light.The pharmacokinetics of PVP-coated β-elemene liposomes were studied compared with conventional liposomes and elemene emulsion. The concentration in plasma handled by statistical moment method and 3P87 showed no obvious disparity. The bioavailability of PVP coated β-elemene liposomes was 140. 2 ± 7. 5% compared with conventional liposomes.