Preparation And Quality Of Irinotecan Long-circulating Nanoliposomes And Study Of Its In Vitro Antitumor Activity

Purpose:To optimize the formation of irinotecan loaded long circulation lipsome, and investigate its standards. To conduct detailed research on its antitumor activities on colorectal cancer cells SW480, liver cells HepG2, breast cancer cells MCF-7of ree irinotecan, blank long cycle of liposome, irinotecan-based long cycle of liposome. We used fluorescent dyes to investigate the effects for the morphology of MCF-7cell.Methods:(1) Preparation of the irinotecan loaded long circulation lipsomeAccroding to the entrapment efficient and particle size, we choosed four kinds of preparation methods to determine the best preparation method. At last, we used the ethanol injection-ammonium sulfate gradient method to prepare the lipsome. Then adopted the single factor prescription for the identification of factors affecting irinotecan liposome, to confirm the best prescription.(2) Characterization of irinotecan loaded long circulation lipsomeOn the basis of the best prescription, we evaluated the particle size, zeta potential, shape, entrapment efficient, release in vitro, stability, et al.(3) Anti-cancer activity of irinotecan loaded long circulation lipsomeWe choosed the human rectal cancer cell SW480, lung cancer cell HepG2, and breast cancer cell MCF-7as model cells. The influences of growth inbition of different concentrations of CPT-11, CPT-11-loaded lipsomes, and blank lipsomes. At the same time, we investigated the effects of CPT-11, CPT-11-loaded lipsomes, and blank lipsomes on the cell morphometry of MCF-7. Results:(1) Preparation of the irinotecan loaded long circulation lipsomeWe choosed the ethanol injection-ammonium sulfate gradient method to prepare the lipsome. It had small particle size and uniform size distribution. The encapsulation rate was high. The best preparation was: spholipids400mg, to make its concentration100mg/mL, cholesterol80mg, PEG400040mg, F-6880mg, were dropped into ammonium sulfate by the concentration of0.2mol/L of13mL. The volum of ammonium sulfate against the volume of ethanol was3:1. The lecithin against irinotecan, PEG4000, and F-68was10:1,10:1, and5:1. On the condition of55℃water bath and N2, the mixed solution was mixed20min. We got the blank long cycle liposomes. The blank liposome was dialysised against saline to remove the ammonium sulfate in the external water phase, formed inside and outside ammonium sulfate gradient. The irinotecan solution was dropped into the liposome. Adjusted the foreign phase pH value, incubated10min at55℃. We got the irinotecan-loaded long cycle nano-liposomes.(2) Characterization of irinotecan loaded long circulation lipsomeAccording to the best the best prescription, the average size of irinotecan loaded long circulation lipsome was about110nm, zeta potential was about-15mV, and the encapdulation efficiency was about92%, and the lipsomes were spherical in shape. The drug release of irinotecan loaded long circulation lipsome was in accrod with weibull equation, lnln[100/(100-Q)]=0.3845lnt-1.2134, R2=0.9747.(3) Anti-cancer activity of irinotecan loaded long circulation lipsome Both the CPT-11and CPT-11loaded long circulation lipsome killed SW480, HepG2, MCF-7were in a concentration and time dependent manner in vitro. While at the same concentration, drug-loaded lipsome had more potent killing function than that of free CPT-11. According to fluorescent microscopy, CPT-11loaded lipsome induced MCF-7cell changed their morphometry.Conclusions:We used the ethanol injection-ammonium sulfate gradient method to prepare the lipsome. It could protect the lactone, so it prolonged the circulation time, and enhanced the anti-cancer activity. The study enriched research content of irinotecan lipsome, so it had a broad application aspects.