Sensitive, simple and rapid spectrofluorimetric and spectrophotometric   methods were developed for the determination of Irbesartan (IRB) and Bisoprolol hemifumarate (BPH) in their tablets dosage form. Both methodologies are based on charge transfer reaction between the studied drugs and 7-Chloro-4-nitrobenzen-2-oxa-1, 3-diazole NBD-Cl. The developed orange products were measured in the appropriate solvent fluorometrically at 534 and 538 nm after excitation at 465 and 470 nm for IRB and BPH, respectively. The fluorescence–concentration plots were rectilinear over the range of 2.5–8 μg/mL for IRB and 6–16 μg/mL for BPH with lower detection limits of 0.18 and 0.39 μg/mL and a lower quantification limit of 0.55 and 1.17 μg/mL for IRB and BPH, respectively. The spectrophotometric method is based on measuring the orange colored products which were developed upon charge transfer complex formation between the studied drugs and (NBD-Cl) in organic media. This showed absorption maxima at 476 nm and 479 nm for IRB and BPH, respectively. The absorbance–concentration plots were rectilinear over the range of 20–90 μg/mL for IRB and 40–160 μg/mL for BPH with lower detection limits of 1.37 and 3.98 μg/mL and lower quantification limits of 4.17 and 12.06 μg/mL for IRB and BPH, respectively. Both methods were successfully applied to the analysis of the two selected drugs. The current study showed that the results were in good agreement with the reference methods.

A novel stability-indicating HPLC method was developed and validated for quantitative determination of sotalol-HCl in bulk powder and in tablets. Isocratic HPLC method, using a C 18 reversed phase column with mobile phase of 80 mM potassium dihydrogen phosphate and acetonitrile (90:10, V/V) was investigated to separate the drug from its stress degradation products. The flow rate was 0.8 mL/min, column oven temperature was ambient and detection was performed at 227 nm. Sotalol-HCl was subjected to the stress conditions of hydrolysis (acid and base), oxidation and photolysis. Stress degraded samples were analyzed by the developed procedure. The analyte was well separated from its degradants. The described method showed excellent linearity over a range of 5-100 g/mL. The determination coefficient (R 2 ) for sotalol-HCl was 0.9999. Limits of detection and quantification were 1.8 g/mL and 5 g/mL, respectively. Degradation of sotalol-HCl was observed in acid and in 30% H 2 O 2 conditions only. The drug was found to be stable in the other stress conditions attempted. The percentage recovery of sotalol-HCl ranged from 98.92 to 99.65% in tablets. The developed method was validated with respect to the linearity, accuracy (recovery), precision, specificity and robustness. The forced degradation studies proved stability indicating power of the method.

This study represents simple atomic absorption spectroscopic and spectrophotometric methods for determination of pioglitazone hydrochloride (PGZ-HCl) and carvedilol (CRV) based on formation of ion-pair associates between drugs and inorganic complex, bismuth(III) tetraiodide (Method A) and between drugs and organic acidic dyes, fast green and orange G (Method B). Method A is based on formation of ion-pair associate between drugs and bismuth(III) tetraiodide in acidic medium to form orange-red ion-pair associates, which can be quantitatively determined by two different procedures. The formed ion-pair associate is extracted by methylene chloride, dissolved in acetone, dried, and then decomposed by hydrochloric acid, and bismuth content is determined by direct atomic absorption spectrometric technique (Procedure 1) or extracted by methylene chloride, dissolved in acetone, and quantified spectrophotometrically at 490 nm (Procedure 2). Method B is based on formation of ion-pair associate between drugs and either fast green dye or orange G dye in acidic medium to form ion-pair associates. The formed ion-pair associate is extracted by methylene chloride and quantified spectrophotometrically at 630 nm (for fast green dye method) or 498 nm (for orange G dye method). Optimal experimental conditions have been studied. Both methods are applied for determination of the drugs in tablets without interference.

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Objectives: In the current study a simple and precise four conductometric methods were introduced for determination of Losartan Potassium (LK) in pure form and tablets. Methods: Method A is based on titration of LK using phosphotungstic acid, method B is based on titration of LK using bromocresol purple dye, method C is based on titration of LK using mercury (II) chloride, and method D is based on titration of LK using cupric chloride. Results: LK was found to be linear in the concentration range of 3–20 mg/mL for all methods except for method C, the concentration range was 1–12 mg/mL. The obtained percentage recoveries for the four methods ranged from 99.69% to 100.53%; the relative standard deviation values were not exceeding two for all methods. Conclusion: The suggested methods were successfully applied for the determination of LK in tablets, with results in close agreement at 95% confidence level with those obtained using the reference spectrophotometric method.