Sustainable eco-friendly ratio-based spectrophotometric and HPTLC-densitometric methods for simultaneous analysis of co-formulated anti-migraine drugs with overlapped spectra

Considering the green chemistry perspective and improving the environmental impact of quality control labs; two direct techniques with less hazardous solvents, less waste production and less energy consumption were developed for simultaneous analysis of Aspirin and Metoclopramide in bulk powder and pharmaceutical formulation. The ratio between the two drugs in their co-formulated preparation is very challenging; (90: 1, Aspirin: Metoclopramide). The first technique is spectrophotometry using simple mathematical operations; ratio difference and derivative ratio–zero crossing. The second technique is high-performance thin-layer chromatography (HPTLC) -densitometry which used a mobile phase consisting of cyclo-hexane: methanol: methylene chloride in a ratio of (1:4:1, v/v/v). The greenest solvents which give acceptable resolution were chosen. Following the International Conference on Harmonization (ICH) guidelines, the methods were found to be accurate, precise, and selective. Those methods were statistically compared to the reported spectrophotometric method and the results proved that there is no significant difference in accuracy and precision. Furthermore, the developed methods were assessed using the Analytical Eco-scale, Green Analytical Procedure Index (GAPI) and the Analytical Greenness calculator (AGREE), which gave a full image about their greenness profile. The spectrophotometry was found to be an excellent green technique compared to HPTLC with was considered an acceptable green one. The developed HPTLC-densitometric method was used for the first time for the analysis of this binary mixture. The two proposed spectrophotometric methos have advantages over the published methods as they used easy manipulation steps and are applied on the market pharmaceutical formulation. Owing to the advantages of the developed techniques; being green, do not require expensive sophisticated equipment or large volume of solvents; they could be used for routine analysis in quality control aspects. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13065-023-01020-2.