Green Spectrophotometric Resolution Platforms of Spectrally Overlapping Signals of Antihypertensive Ternary Pharmaceutical Formulation: Application to Content Uniformity Testing

Hypertension is one of the leading causes of death globally and a major risk factor for different cardiovascular outcomes. This led to continuous discovery of new drugs and on-going update of drug combinations. In the present work, sustainable eco-friendly spectrophotometric methods were developed and validated for the estimation of amiloride hydrochloride (AML), hydrochlorothiazide (HCT) and timolol maleate (TIM) in their ternary pharmaceutical formulation. The proposed methods are inspired based on the unique spectral characteristics of this mixture including spectral extension of AML over both HCT and TIM spectra. AML exhibits UV maximum at 362.0 nm that permits its direct estimation by zero order spectrophotometric method without any interference in a linear range of 2.0-20 mu g/mL. While for the estimation of HCT and TIM, two methods were applied. The first method is dual wavelength in ratio spectra, while the second one is ratio subtraction in conjunction with the first derivative of ratio spectra method. The two methods were found linear over the concentration range of 2.0-25 mu g/mL for HCT and 5-80 mu g/mL for TIM. The suggested methods were successfully adopted for the evaluation of the studied drugs in their marketed dosage form and further implemented for content uniformity evaluation. Additionally, method greenness profile was assessed using different assessment metrics.