Ecofriendly colorimetric set-up coupled with mathematical filtration strategy for simultaneous determination of ipratropium and fenoterol in their novel anti-asthmatic metered dose inhaler.

Ipratropium bromide (IPR) and fenoterol hydrobromide (FEN) are well-known medications for treating asthma and chronic obstructive pulmonary disease (COPD). A simple, feasible, efficient, and cost-effective colorimetric assay has been established for determination of the newly introduced co-formulated metered dose inhaler (Atrovent(®) comp HFA). The developed method is based on the properly optimized reaction of drugs under study with the charge transfer reagent 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), resulting in orange-colored complexes measured at 464.3 and 514.0 nm for IPR and FEN, respectively. Smoothly applicable and easily manipulated resolution method, Vierordt's method, based on straightforward mathematical equations that do not need complicated software was implemented for the simultaneous determination of IPR and FEN. The proposed methodology can be applied in routine analysis enabling fast and economical determination of the combined dosage form without the need for previous separation steps. The validity of the proposed colorimetric method was thoroughly assured as per ICH guidelines with acceptable accuracy and precision. The linearity ranges for IPR and FEN were 5.0-55.0 µg/mL and 10.0-40.0 µg/mL, respectively. Using cutting-edge software metric tools, namely the analytical greenness (AGREE), and complementary green analytical procedure index (ComplexGAPI), the greenness profile of the suggested method was clearly evaluated. The method also conformed well to the recently published blueness (BAGI tool) and whiteness (RGB12 tool) concepts.