OBJECTIVETo prepare sinomenine hydrochloride delayed-onset sustained-release tablets.

METHODThe tablets containing sinomenine hydrochloride were prepared by dry-compression coating technique with the ratio of HPMC in core tablet and the ratio of HPMC in coating film as the influence factors and the lag-time and release rate as the evaluation parameters. Experiments were done on the central composite design, the data were simulated by using multi-linear equation and second-order polynomial equation. The possibly optimal formulation was predicted by response surface method. The dissolution date (lag-time and release rate) of the tablets prepared under the optimum condition were compared with the predicted. The drug released mechanism of the tablet were studied by Model-fitted of drug released within 6-15 h with zero-order, Higuchi and Peppas equation, respectively.

RESULTThe lag-time and release rate were simulated using second-order polynomial equation, regression coefficients of the two parameters were 0.9901 and 0.9876, respectively. Bias between the observed and predicted values of lag-time and release rate were -3.15% and -0.34%, respectively. The lag-time of the tablet prepared under the optimum condition in vitro was about 6 h, then drug released from the tablet within 6-15 h was found to conform to zero-order kinetics and was controlled by bulk erosion mechanism.

CONCLUSIONSinomenine hydrochloride delayed-onset sustained-release tablets release drug slowly after lag time. The models developed in this study are proved to be highly predictable.