Abstract Simple, precise, accurate and specific spectrophotometric methods are progressed and validated for concurrent analysis of Furosemide (FUR) and Spironolactone (SPR) in their combined dosage form depend on spectral analysis procedures. Furosemide (FUR) in the binary mixture could be analyzed at its λmax 274 nm using its recovered zero order absorption spectrum using constant multiplication method (CM). Spironolactone (SPR) in the mixture could be analyzed at its λmax 238 nm by ratio subtraction method (RS). Concurrent determination for FUR and SPR in their mixture could be applied by amplitude modulation method (AM), absorbance subtraction method (AS) and ratio difference (RD). Linearity ranges of FUR and SPR were (2.0µg/mL-22.0 µg/mL) and (3.0µg/mL-30.0 µg/mL), respectively. Specificity of the proposed spectrophotometric methods was examined by analyzing the prepared mixtures in laboratory and was applied successfully for pharmaceutical dosage form analysis which have the cited drugs without additives contribution. The proposed spectrophotometric methods were also validated as per as the guidelines of ICH. Statistical comparison was performed between the obtained results with those from the official methods of the cited drugs, using one-way ANOVA, F-test and student t-test. The results are exhibiting insignificant difference concerning precision and accuracy.

Simple, specific, accurate and precise spectrophotometric methods were developed and validated for simultaneous estimation of Ciprofloxacin hydrochloride (CIP) and Hydrocortisone (HYD) in their pure form and pharmaceutical dosage form. Two new spectrophotometric methods were applied: extended ratio subtraction (EXRSM) and ratio difference (RDSM) methods. The results were compared to three well-established methods: Mean centering of ratio spectra method (MCR), Isoabsorpative point spectrophotometric method (IsoM) and Absorbance ratio method (ARM). The linearity range for the spectrophotometric methods was found to be (2-14 μg/mL) and (1-14 μg/mL) for CIP and HYD respectively. The selectivity of the developed methods was investigated by analyzing laboratory prepared mixtures of the two drugs and their combined dosage form. The results obtained from the proposed methods were statistically compared using one-way analysis of variance (ANOVA) where no significant difference was observed between the new (EXRSM and RDSM) and the well-established methods which prove their validity for the analysis of this binary mixture. The methods were validated as per ICH guidelines regarding accuracy, precision, repeatability and robustness; which were found to be within the acceptable limits. The new methods were simple, sensitive and don't need a special program, so they could be easily applied as alternative methods to LC methods in quality control laboratories lacking the required facilities for those techniques.