OBJECTIVE To investigate the possibility of poly(ε caprolactone block D,L lactide) nanoparticles (PCLA NP) as a
new kind of drug carrier.METHOD INS PCLA NP was prepared by double emulsification solvent evaporation method. Its morphology was examined by transmission electron microscope. HPLC method was established for INS in INS PCLA NP, the encapsulation ratio of INS on INS PCLA NP was estimated, and the influence factors to size and encapsulation ratio were investigated. The in vitro INS release behaviour from nanoparticles was determined. An “antibody capture” procedure was devised for testing encapsulation mechanism. The diabetic rats model was established and to evaluate the hypoglycemic effects after subcutaneous administration of INS PCLA NP. The pharmacological bioavailability (PBA) was calculated from the area above the curve (AAC).RESULTS The mean diameter of INS PCLA NP was 167.3 nm, while the encapsulation ratio of INS reached to 37.79%. It was demonstrated that the most (about 53%) encapsulated INS was on the surface of the nanoparticles, it could be measured by “antibody capture” experiment. INS release from INS PCLA NP appeared to consist of two components with an initial rapid release followed by a slower exponential stage. After subcutaneous administration of INS PCLA NP 12u·kg -1 , the hypoglycemic effect was significant. The pharmacological bioavailability of INS PCLA NP was 74.76%.CONCLUSION PCLA NP might be a potential new drug carrier.