In the past few decades the analytical community has been focused on eliminating or reducing the usage of hazardous chemicals and solvents, in different analytical methodologies, that have been ascertained to be extremely dangerous to human health and environment. In this context, environmentally friendly, green, or clean practices have been implemented in different research areas. This study presents a greener alternative of conventional RP-HPLC methods for the simultaneous determination and quantitative analysis of a pharmaceutical ternary mixture composed of telmisartan, hydrochlorothiazide, and amlodipine besylate, using an ecofriendly mobile phase and short run time with the least amount of waste production. This solvent-replacement approach was feasible without compromising method performance criteria, such as separation efficiency, peak symmetry, and chromatographic retention. The greenness profile of the proposed method was assessed and compared with reported conventional methods using the analytical Eco-Scale as an assessment tool. The proposed method was found to be greener in terms of usage of hazardous chemicals and solvents, energy consumption, and production of waste. The proposed method can be safely used for the routine analysis of the studied pharmaceutical ternary mixture with a minimal detrimental impact on human health and the environment.

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& Two accurate and sensitive stability-indicating methods for the determination of rosuvastatin calcium in the presence of its acid degradation products are presented. The first method utilizes quantitative spectrodensitometric evaluation thin-layer chromatography (TLC) of rosuvastatin calcium in the presence of its acid degradation products, using ethyl acetate=methanol=ammonia (7:3:0.01, by volume) as a mobile phase. Chromatograms are scanned at 245 nm. This method analyzes rosuvastatin calcium in a concentration range of 0.6-3.4 lg=band with mean percentage recovery of 99.78 AE 1.42. The second method is a high-performance liquid chromatography (HPLC) method for the simultaneous determination of rosuvastatin calcium in the presence of its acid degradation products. The mobile phase consists of water=acetonitrile=methanol (40:40:20, by volume). The standard curve of rosuvastatin calcium shows a good linearity over a concentration range of 10-60 lg mL À1 with mean percentage recovery of 100.22 AE 0.86. These methods were successfully applied to the determination of rosuvastatin calcium in bulk powder, laboratory-prepared mixtures containing different percentages of the acid degradation products, and pharmaceutical dosage forms. The validity of results was assessed by applying standard addition technique. The results obtained were found to agree statistically with those obtained by a reported method, showing no significant difference with respect to accuracy and precision.

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Two accurate and sensitive chromatographic methods have been developed and validated for simultaneous determination of cinnarizine (CIN) and dimenhydrinate (DIM). The first method uses simultaneous quantitative thin layer chromatography (TLC) spectrodensitometric evaluation of them, using ethyl acetate:methylene chloride (8 : 2 by volume) as a mobile phase. Chromatograms are scanned at 254 nm. This method analyzes CIN in a concentration range of 0.5-6 µg per band with mean percentage recovery of 99.78 ± 1.001 and DIM in a concentration range of 1-6 µg per band with mean percentage recovery of 99.87 ± 1.319. The second method is high-performance liquid chromatography using methanol:acetonitrile:water [85 : 10 : 5, by volume +0.5% tri ethyl amine (TEA)] as a mobile phase. The linearity was found to be in the range of 10-60 and 5-60 µg mL(-1) for CIN and DIM, respectively. The methods were successfully applied to the simultaneous determination of CIN and DIM in bulk powder, laboratory-prepared mixtures and pharmaceutical dosage forms. The validity of results was assessed by applying standard addition techniques. The results obtained are found to agree statistically with those obtained by a reported method, showing no significant difference with respect to accuracy and precision.

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Application and validation of eco-friendly TLC-densitometric method for simultaneous determination of co-formulated antihypertensive agents.