Preparation And Evaluation Of Gefitinib Liposome Entrapped Cyclodextrin Complex

ObjectiveGefitinib is a new type of non-small cell lung cancer drugs. As a kind of selective epidermal growth factor tyrosine kinase inhibitors, gefitinib can reduce the activity of tyrosine kinase and block information transfer between selective epidermal growth factor in tumor cells. At present, gefitinib has been listed only as a tablet, and there exist problems of oral absorption slowly, widely distributed in the body, degree of gastrointestinal side increased with the drug dose. Liposomes have attracted considerable attention as a novel drug delivery because of its good biological compatibility and potential to be modified. However, traditional liposomes have disadvantages in easy elimination by reticuloendothelial system and low encapsulation efficiency of hydrophobic drugs, which could reduce the drug efficiency.For reasons above all, the liposomes were prepared by thin film method with freeze-thawing steps. Gefitinib was chosen as a model drug, and gefitinib-in-cycbdextrins-in-liposome was prepared. Furthermore, we use D-mannose and octadecylamine to formed the prescription of gefitinib liposomes so that it could increase the drug assemble in lung, decrease the dose and the rate of adverse reaction, increase the therapeutic index for lung. In this experiment, we also evaluate the targeting of gefitinib-in-cycbdextrins-in-liposome by pharmacokinetics in rat and tissue distribution in mice.MethodsAfter reading the relevant literature, we established HPLC analysis method of gefitinib in liposomes suspension, rat plasma and mice tissue. We also made a systematic study on methodology on the analysis method.We used the thin film method with freeze-thawing steps to make the liposomes of gefitinib in lung modified by D-mannose after combining related literature with the results of preliminary experiment. We investigated a numbers of factors of formulation and technology process which had great influence the encapsulation efficiency. The encapsulation efficiency was taken as criterion to optimize the quality rate. On these basis, seven factors and there levels orthogonal design was chosen to optimize the formula and prepration methods of gefitinib liposomes modified by D-mannose. According to analysis of range to range to finalize gefitinib liposomes best prepration methods and formula.We made a preliminary evaluation of stability and quality. Evaluation of stability included storage temperature of liposomes preparation and leakage rate. Evaluation of quality section included appearance, pH value, morphological structures, size distribution, surface potentials, entrapment efficiency we cumulative release in vitro of liposome.In the end, the studies of pharmacokinetics in rat and tissue distribution in mice of gefitinib liposomes were made by compared with the gefitinib solution made in lab.ResultsAfter reading the relevant literature, the concentration of gefitinib in mice and rat was detemined by HPLC. The results of systematic study on methodology on the chromatographic conditions showed that the method had good specialization, linear relationship, precision and recovery.The encapsulation efficiency was taken as criterion to optimize the quality rate. Through the orthogonal formulation and the test of technology process, we got the best technology process as follows:the ratio of soybean lecithin and cholesterol was 3:1; the ratio of gefitinib and soybean lecithin was 120; the ratio of octadecylamine and soybean lecithin was 1:15, the temperature of the preparation was 35℃, hydration medium was purified water which had Hydroxypropyl-β-Cyclodextrin (100 mg·mL-1) and D-mannose(1.5 mg·mL-1), the temperature of hydration was 25 ℃, stored in 4℃ after repetitive freeze-thawing for three times.The liposomes made in lab was yellowish suspension which mean pH value was 6.5, mean particle size was 320.4 nm, meam surface potential was+34.29 mV, mean entrapment efficiency was 51.02%. In vitro release test, the percent of cumulative of gefitinib liposomes modified by D-mannose was less than gefitinib solution after 48 h in PBS (with 30% methanol in it).The pharmacokinetics study was took in SD rats with the reference of gefitinib solution, the AUC, MRT, T1/2P of gefitinib liposomes group were 8.384 μ·gh·mL-1,8.410 h,6.145 h respectively.The tissue distribution study were took in mice with the reference of solution of gefitinib liposomes and the main pharmacokinetics parameters as followed:ConclusionUnder all experiment conditions, gefitinib liposomes has stable entrapment efficiency, a satisfactory stability andeven distribution in size, which can be stablility stored in 4℃ for 30 days without precipitation. The release study shows sustained release behavior in vitro.The study in rats suggests that the gefitinib liposomes can increase the drug concentration in plasma and prolongate the circulation.The study in mice shows that the gefitinib liposomes can make drug fouce to the lung.