Spectrophotometric approach for deconvolving overlapped spectra of antihypertensive drug mixtures using UV detection: an eco-friendly method

Abstract

This study presented four simple, environmentally friendly, chemometric methods for the determination of Amlodipine besylate and Telmisartan, When analyzed together, these drugs exhibit spectral overlapping; therefore, by adopting spectral manipulation, drugs are quantified simultaneously. The methods are namely the first derivative spectrophotometric method, the ratio difference method, the first derivative ratio method and the amplitude factor method. The methods showed detection limits ranging from 0.1211 to 0.4304 µg/mL and 0.0773 to 0.5640 µg/mL for Amlodipine besylate and Telmisartan, respectively, with good adherence to International Council for Harmonization standards. The methods were compared with the reported HPLC method using the student t-test and F-test, where the results showed no significant difference. For this method, a green solvent such as propylene glycol is selected through the Green solvent selection tool with a greenness score of 7.8 and the sustainability of the solvent is evaluated using spider diagram. Methods were assessed for their eco-friendliness and sustainability using novel tools such as Blue Applicability Grade Index, Green Analytical Procedure Index and RGB model with respect to White and Green analytical chemistry principles. Using Greenness tools for this UV-spectroscopy method improves both safety and effectiveness compared to expensive and laborious HPLC techniques. Hence, this study suggests employing easy and renewable UV spectrophotometric technologies for traditional analysis.

Keywords: Amlodipine besylate; Spectral overlap; Sustainable method; Telmisartan; UV spectroscopy.

Fig. 1

Spectral overlap of Amlodipine besylate and Telmisartan in 10:8 ratio

Fig. 2

a) D¹ spectra of TEL (2–12 µg/mL) and AMLB in propylene glycol b) D¹ of AMLB (5–30 µg/mL) and TEL in propylene glycol c) RD spectra of AMLB using TEL (6 µg/mL) in propylene glycol d) RD spectra of TEL using AMLB (15 µg/mL) in propylene glycol

Fig. 3

a) DD¹ spectrum of TEL (2–12 µg/mL) b) DD¹ of AMLB (2–12 µg/mL) c) AMLB derivative spectrum ranges from 5–30 µg/mL with no influence from TEL d) TEL derivative spectra at 237 nm in the range of 2–12 µg/mL where both AMLB and TEL show absorbance

Fig. 4

a) Picture displaying the results for Propylene glycol using Green solvent selection tool b) Primary spider diagram for propylene glycol c) Secondary spider diagram of propylene glycol

Fig. 5

a) BAGI pictogram depicting the result of proposed method b) GAPI result for the proposed method c) Whiteness assessment result using RGB model