Studies on the formulation and preparation of carboxymethyl chitosan-coated vinpocetine nanoliposomes and their drug release properties in vitro

OBJECTIVE To study the optimal formulation, preparation and drug release in vitro of the carboxymethyl chitosan (CMC)-coated vinpocetine (VIN) nanoliposomes.METHODS VIN liposomes were prepared by the film dispersion method. CMCs with different substitution were used to coat the liposomes followed by extruding through high pressure homogenizer. Orthogonal design was applied and the encapsulation efficiency was chosen as index to screen the optimal formulation. The zeta potential, mean size and size distribution were determined by Zetersizer. Dialysis in vitro was employed to study the drug release from the CMC-coated nanoliposomes.RESULTS The optimal formulation of the CMC-coated VIN nanoliposomes was as follows: the ratio of VIN and (egg lecithin+cholesterol) was 1∶20; the ratio of cholesterol and egg lecithin was 1∶6; weight percentage of mannitol in the formulation was 50%; the substituted degree of CMC was 50%. The optimal nanoliposomes had promising appearance and coating layer. The encapsulation efficiency was (72.2±2.4)%, while the zeta potencial and mean size was (-11.6±2.1)mV and (94.8±5.9)nm, respectively(n=3).The drug release in vitro was accorded with the Higuchi equation: Q=-0.352 20+0.206 28t1/2,r=0.992 5.CONCLUSION The CMC-coated VIN nanoliposomes had promising encapsulation efficiency, nanometeric sizes and significant sustained-release property in vitro.