Simultaneous spectrophotometric determination of pyrantel pamoate and febantel in pharmaceutical preparations using partial least-squares regression

The multivariate spectroscopic determination of the combination of pyrantel pamoate (PP) and febantel (FB) in pharmaceutical preparations was carried out by partial least-squares regression. The UV absorbance spectra of standard mixtures of PP and FB were measured at concentrations ranging from 5.76–11.52 and 6–12 μg/mL, respectively, in a diluent solution of methanol and acetonitrile. The best model was selected with variable selection (280–320, 380–400 nm), 2 latent variables and mean centered. External validation was performed using 13 different mixtures, which provided prediction errors lower than 1%. The method was validated in accordance with international and Brazilian guidelines. This method was successfully employed to quantify the drug content in two different pharmaceutical formulations (solid — capsules, liquid — oral suspensions) with good prediction capacity. Furthermore, its advantages include the use of simple and accessible reagents and equipment, and a low operating cost.