Study on the preparation and drug release in vitro of ocular N-trimethyl chitosaN-coated insulin nanoliposomes-in situ gels

Objective To prepare ocular insulin(INS)-loaded cationic nanoliposomes-in situ gels(ISG)and investigate their related characteristics and drug release profiles in vitro.Methods Insulin nanoliposomes(INSL) were prepared by the reverse evaporation method,then coated by N-trimethyl chitosan(TMC60).The optimal amount of poloxamer407 was selected according to the gelation temperature.A novel membraneless model was used to study the drug release in vitro.Results The mean diameter of INSL-ISG before TMC60 coating was(92.36±0.20) nm with the Zeta potential of(-19.50±0.30) mV.The mean diameter of INSL-ISG after TMC60 coating was(93.93±0.19) nm with the Zeta potential of(13.23±0.15) mV.The optimal concentration of poloxamer407 in the formula was 25% with the gelation temperature of 23.9 ℃ and 34 ℃ before and after simulation tear dilution.Both the drug release in vitro and gel dissolution profiles of TMC60-INSL-ISG exhibited the characteristics of zero order kinetics.Conclusion TMC60-INSL-ISG showed the advantages of cationic liposomes and in situ gels,and could delay the drug release in vitro,which provided the basis for the further study on the cornea residence time promotion.