Salamide

Captopril and hydroChlorothiazide pure samples were kindly supplied from (Pharco Pharmaceuticals Co. Alexandria, Egypt). Their purity was verified using the reported HPLC method [10 (link)] and the results were 99.83% and 99.91%, respectively. Chlorothiazide and salamide standards were purchased from (Sigma-Aldrich Chemie GmbH, Germany) and their purity was labeled 99.90% and 99.87%, respectively. Based on the literature survey, captopril disulphide was prepared from the supplied sample of captopril via oxidative degradation using an iodine solution [4 ].

HPLC grade solvents were used, and water was double distilled. Orthophosphoric acid, hydrochloric acid, sodium tetraborate decahydrate and ammonia solution (25%) were all obtained from Sigma Aldrich (Steinheim, Germany). Ethyl acetate and ethanol were purchased from Fisher scientific (UK).
Pure amiloride hydrochloride, with purity of 99.81 ± 1.51%, according to the official method [13 ], was purchased from Sigma Pharmaceuticals Industries (El Monofeya, Egypt). Pure hydrochlorothiazide was obtained from October Pharma (Cairo, Egypt) and according to the official method [13 ], its purity was found to be 100.24 ± 1.42%. Timolol Maleate was purchased from Orchidia Pharmaceutical Industries (Obour City, Egypt) with 99.93 ± 1.12% purity according to the official method [16 ]. Hydrochlorothiazide impurities; salamide and chlorthiazide, were acquired from Sigma Aldrich Chemie (Steinheim, Germany). According to supplier certificate of analysis, their purities were reported to be 99.70 and 99.60%, respectively. Moducren^® Tablets were manufactured by GERDA (Paris, France), Batch No. AJC 066, with labelled claim of 2.5 mg AML, 25 mg HCT and 10 mg TIM per tablet and were purchased from the French local market.