Document resource
Background and Aims To study the pharmacokinetic and pharmacodynamic effects of bupivacaine polylactic acid microspheres in rabbits.Methods The sixteen rabbits were divided randomly into two groups(n=8). One group was single-injected with bupivacaine solution 5 mg/kg subcutaneously, the other group was single-implanted with bupivacaine polylactic acid microspheres 5 mg/kg subcutaneously. A high performance liquid chromatographic method was developed to determine bupivacaine plasma concentration. A rabbit model for evaluation of regional anesthesia was presented on the pharmacodynamic study.Results The HPLC revealed that plasma concentration of bupivacaine reached peak time quickly, Cmax=2.4664µg/ml,then the plama concentration of bupivacaine came down sharply in group A. The plasma concentration of bupivacaine in group B was lower, and concentration-time curve was gently. It showed that peak time delayed and MRT prolonged, Cmax=0.7781µg/ml (P<0.05). The pharmacodynamic study showed that the time of regional sensory blockade in microspheres group was prolonged compared to the injection group (P<0.05).Conclusions Bupivacaine polylactic acid microspheres have sustained-release effect in rabbits, it can provide theory basis for the super long-acting local anesthetics.