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Three smart spectrophotometric methods were developed for the simultaneous estimation of chlorpheniramine maleate and naphazoline hydrochloride, a binary mixture with overlapping spectra, without preliminary separation. These methods include area under the curve (AUC), graphical absorbance ratio (Q-analysis) and isosbestic point spectrophotometry. A comparative study among the methods was done showing the advantages and the disadvantages of each method. Beer’s law is obeyed over the concentration range of 5- 35 and 5-40 μg/ml for chlorpheniramine maleate and naphazoline hydrochloride,respectively (for area under the curve), and 5-40 μg/ml for each drug (for Q-analysis and isosbestic point). All the proposed methods were extensively validated according to the ICH guidelines and the obtained accuracy, precision and repeatability were found to be within the acceptable limits. The selectivity of the proposed methods was tested using laboratory prepared mixtures and assessed by applying the standard ad... more...

A simple, fast, and low-cost method was developed and validated for the separation and determination of neostigmine metilsulfate (Neo), naphazoline hydrochloride (Nap), chlorphenamine maleate (Chl), pyridoxine hydrochloride (Pyr), and dipotassium glycyrrhizinate (Dip) by capillary electrophoresis (CE) for the first time. The separation was achieved in 7 min with 10 mM borate of pH 10.0, ultraviolet detection at 205 nm, and 25 kV applied voltage. The proposed method demonstrates good linearity with r2 between 0.9995 and 0.9998. The repeatability was in the range of 0.23–1.96% with migration time and 0.81–3.46% with peak area for the five components. The limits of detection were 0.10, 0.02, 0.08, 0.17, and 2.44 µg mL−1 for Neo, Nap, Chl, Pyr, and Dip, respectively. The method was successfully applied to the quantitation of the five components in a commercial eye drops with recoveries in the range of 99.01–101.26%. Furthermore, a comparison of the results obtained by CE was made with those obtained by high-p... more...

Procedures were developed for the simultaneous determination of pharmaceuticals in two-component commercial formulations by first-order derivative UV spectrophotometry. Phenylephrine hydro chloride and carbinoxamine maleate in capsules and diphenhydramine hydrochloride and naphazolixehydro hydrocloride in nasal gelly were succesfully assayed. A simple sensitive method in the usual range for the binary preparations has been developed. Average recoveries of the four compounds in the formulations under study were 100.04 ± 1.28% 101.50 ± 2.27 %, 101.59 % 1.24 % and 100.49 ± 2.59 %. more...

A second (D2) derivative spectrophotometric technique has been applied for the determination of diphenhydramine hydrochloride in mixture with naphazoline hydrochloride and in presence of Methylene blue. Diphenhydramine hydrochloride has been extracted with chloroform and D2-value was measured at 255 nm. Naphazoline hydrochloride in the mixture has been determined by direct measurement of its D2 at 273 nm. Methylene blue could be determined in the mixture by direct absorbance measurement at 663 nm. As illustrate example, commercial eye drops was analysed for these two drugs in presence of methylene blue in pharmaceutical preparation. The results obtained were of high accuracy and good reproducibility. more...