SELECTIVE IMPROVEMENTS IN MULTIQUALITY PRODUCTS ASSISTED BY ROTATED PRINCIPAL COMPONENTS

Selective improvements in pharmaceutical multiquality products have be en assisted by rotated principal components. Orthogonal and oblique ro tations of principal components have been applied to evaluate data fro m two production process studies. The purpose of the presented methods is to locate the process variables (X's) that can be used to vary som e quality parameters (Y's), with as minimal influence on other Y's as possible, followed by explicit illustrations of such X-Y relations. Tw o procedures involving varimax rotation are used for this purpose. One , evaluate the loadings from varimax performed on all variables (X's a nd Y's). Two, varimax performed on Y's only, followed by linear regres sion of the varimax Y-scores on X's (VMLR or VPLS) to evaluate the eff ect of X's on certain Y-groups. The VMLR and VPLS were generally found to be more robust methods compared with varimax only. The information derived from the rotation analysis was used to adjust the relevant X- variables in linear regression models developed to estimate precise Y' s. (C) 1998 Elsevier Science B.V. All rights reserved.