Factorial design of experiment for stability studies in the development of a tablet formulation

The stability of chlorpromazine hydrochloride in some hypothetical tablet formulations was evaluated through a fractional factorial design of the type N = 2(6-3). The factors studied were the type of filler (X1), lubricant (X2), binder (X3), disintegrant (X4), the absence or presence of light ( X5 ) and/or humidity ( X6 ). Statistical analysis of the stability data allowed the derivation of a regression equation which determined the magnitude and direction of change of each factor level to optimize drug stability. The significance of the factors could be arranged in the following order: X5 greater than X2 greater than X3 greater than X6 greater than X1. The effects of X4 and the two-factor interaction X2X3 were found to be insignificant. The best multi-component excipient mixture was evaluated on the basis of the information deduced from the factorial design.