Simultaneous Spectrophotometric Quantification of Metamizole Sodium, Pitofenone Hydrochloride, and Fenpiverinium Bromide in a Pharmaceutical Product Using Multivariate Calibration Methods

Abstract

A spectrophotometric method was developed for the simultaneous determination of metamizole sodium, pitofenone hydrochloride, and fenpiverinium bromide in the ternary synthetic mixtures and pharmaceutical products. Partial least squares (PLS-1 and PLS-2 methods) combined with ultraviolet-visible spectrophotometry was applied for the quantitative determination of pharmaceuticals. The linear dynamic ranges for determination of the content of metamizole sodium, pitofenone hydrochloride, and fenpiverinium bromide were between 1 and 50 mg/L, 1 and 15 mg/L, and 60 and 1000 mg/L, respectively. The predicted residual sum of squares (PRESS) and root mean square error (RMSE) statistical parameters for the proposed PLS models were calculated to characterize the prediction abilities of the regression models. The results indicate that the highest prediction error was obtained for fenpiverinium bromide content in both regression models, probably due to its low molar extinction coefficient. This procedure was successfully applied in the control laboratory in the pharmaceutical industry for the rapid estimation of the content of drugs in a pharmaceutical product to avoid expensive and complex chromatography procedures.