Partial least-squares regression for the quantitation of pharmaceutical dosages in control analyses

A spectrophotometric method for the simultaneous determination of the active principle and a flavouring agent in syrups containing additional excipients is proposed. The calibration matrix must include all the variability expected in the samples and this is achieved using laboratory-made mixtures and production samples in order to ensure correct results. The optimum number of principal components for the regression model was selected by using various procedures. The proposed method was used to quantify samples from different production batches. The results are compared with those provided by HPLC.