OBJECTIVETo establish the analytical method for the release kinetic (RK) of Aconitum Brachypodum gel based on the nonlinear mixed effect model (NLMEM), in order to rationally evaluate the drug release process and explain the release mechanism.

METHODThe zero-order kinetic model containing for non-corroded drug system with the random effect was taken as the base model. The fixed effect and random effect factors impacting the drug release were analyzed by PROC NLMIXED of SAS to establish the final typical model. Subsequently, 10 training subsets were randomly extracted from the primary data to respectively their RK models, calculate the corresponding predicted root-mean-square error and average relative error, and evaluate the model stability and prediction accuracy.

RESULTThe burst effect F0 had a very significant effect on the RK model. Among the component factors, carbopol 940 showed an obvious effect on the inherence release speed constant k0 and the concentration gradient change constant a, with different variations on the basis of dosage range. The random effect factors of k0 and a had a significant impact. The final RK model was proved to be stable, effective and reliable in the cross validation.

CONCLUSIONThe drug release kinetic analysis method could be used to rationally evaluate the drug release process and explain the release mechanisms.