Optimized preparation of Silymarin Dropping Pill by a central composite design-response surface method / 中草药

ABSTRACT

Objective Using solid dispersion technique to prepare Silymarin Dropping Pill to accelerate dissolution and to improve bioavailability. A central composite design-response surface method was employed to select the optimum formulations. Methods Independent variables were Poloxamer 188 content and silymarin content, while dependent variables were disintegrating time and percent of silymarin dissoluted at a definite time. Linear, two and three order quadratic models were used to estimate the relationship between independent and dependent variables. Response surfaces were delineated according to best-fit mathematic models and optimum formulations were selected there from. Prediction was carried out through comparing the observed and predicted values. Results Three order quadratic equation was the best-fitted mathematic models to describe the relationship between dependent and independent variables, with a regression coefficient of 0.998. Bias between observed and predicted values of disintegrating time and dissolution percentage of optimum formulation dropping pill were negligible, indicating the high predictability of the fit models. Percent dissolution of Silymarin Dropping Pill at 60 min was 19 times as that of conventional tablets. Conclusion Dissolution speed of silymarin can be effectively improved through incorporating into dropping pills. It shows that the optimum mathematic model is highly predictive. The central composite design-response surface method can be fairly used in formulation screening.