Green method by diffuse reflectance infrared spectroscopy and spectral region selection for the quantification of sulphamethoxazole and trimethoprim in pharmaceutical formulations

Abstract

An alternative method for the quantifi cation of sulphametoxazole (SMZ) and trimethoprim (TMP) using diffuse refl ectance infrared Fourier-transform spectroscopy (DRIFTS) and partial least square regression (PLS) was developed. Interval Partial Least Square (iPLS) and Synergy Partial Least Square (siPLS) were applied to select a spectral range that provided the lowest prediction error in comparison to the full-spectrum model. Fifteen commercial tablet formulations and forty-nine synthetic samples were used. The ranges of concentration considered were 400 to 900 mg g -1 SMZ and 80 to 240 mg g -1 TMP. Spectral data were recorded between 600 and 4000 cm -1 with a 4 cm -1 resolution by Diffuse Refl ectance Infrared Fourier Transform Spectroscopy (DRIFTS). The proposed procedure was compared to high performance liquid chromatography (HPLC). The results obtained from the root mean square error of prediction (RMSEP), during the validation of the models for samples of sulphamethoxazole (SMZ) and trimethoprim (TMP) using siPLS, demonstrate that this approach is a valid technique for use in quantitative analysis of pharmaceutical formulations. The selected interval algorithm allowed building regression models with minor errors when compared to the full spectrum PLS model. A RMSEP of 13.03 mg g -1 for SMZ and 4.88 mg g -1 for TMP was obtained after the selection the best spectral regions by siPLS.

Quercetin-Crosslinked Chitosan Films for Controlled Release of Antimicrobial Drugs

“…The main TMP peaks are assigned as follows: at 3,469 and 3,317 cm −1 to N–H stretching vibration, from 1,653 to 1,631 cm −1 to amine bending, from 1,458 cm −1 to C=C aromatic stretching, at 1,235 and 1,124 cm −1 to C–N and C–O stretching, respectively, and at 830 cm −1 to C–H bending from the substituted aromatic ring ( Ungurean et al, 2013 ; Da Silva et al, 2016 ). The TMP peaks are visible on the CS/TMP film, without a clear difference, except a broadening of the area of H bonding in 3,200–3,600 cm −1 , which may be due to the formation of additional hydrogen bonds as reported by Acharya et al (2021) , whereas on films with quercetin, TMP peaks are less evident, and some band shifts are observed, in particular the band at 1,660 cm −1 .…”

Chemometrics in analytical chemistry – an overview of applications from 2014 to 2018

“…Support vector regression (SVR) model was more accurate when compared to PLSR model with values for RMSEP between 0.18 -0.27 g mL -1 while the values for PLSR were RMSEP from 0.27 to 0.30 g mL -1 14 . The synergy PLS (siPLS) model combined with FTIR showed the best results compared to the full spectrum PLS model for the quantification of active ingredient pharmaceutical in tablets which values highlight by authors was RMSECV of 15.28 mg g -1 and R 2 of 0.99 for sulphamethoxazole and RMSECV of 7.52 mg g -1 and correlation of 0.98 for trimethoprim 15 . Cantor et al 16 evaluated the ability of different analytical techniques such X ray diffraction, FTIR, Raman and NIR to detect melamine levels in gelatin (pharmaceutical component).…”

Simultaneous determination of valsartan, amlodipine besylate and hydrochlorothiazide in tablets by near infrared

“…Most recently applications have been published showing that spectral region selection using suitable algorithms such as interval partial least squares (iPLS) and synergical partial least squares (siPLS) can significantly improve the performance of PLS regression techniques (Xiaobo et al, 2010;Shi et al, 2012;Piantavini et al, 2015;Silva, Flores and Parisotto, 2016). Moreover, spectral region selection containing relevant chemical information is especially important for spectra with strong band overlapping such as pharmaceutical formulations (containing active substance, impurities and excipients) (Silva et al, 2009;Piantavini et al, 2014).…”

“…Moreover, spectral region selection containing relevant chemical information is especially important for spectra with strong band overlapping such as pharmaceutical formulations (containing active substance, impurities and excipients) (Silva et al, 2009;Piantavini et al, 2014). Recent papers in the literature describe assay methods for tablets containing triple combination of valsartan (VAL), hydrochlorothiazide (HCT) and amlodipine besylate (AML) by HPLC and ultraviolet spectroscopy (UV) (Shaalan et al, 2013;Darwish et al, 2014).…”