Application of first derivative spectrophotometry to the determination of loperamide hydrochloride in dosage forms and in presence of its degradation products

A simple, specific and accurate derivative spectrophotometric method was developed for the determination of loperamide hydrochloride in pure and dosage forms as well as in presence of its degradation products. The method depends on measuring the first derivative spectral response of the cited drug at 226 nm, where the corresponding degradation products exhibited no contribution. Reliability of the method was proved using synthetic mixture of the drug with its corresponding degradation products. Also, different pharmaceutical dosage forms of the cited drug were assayed by the proposed method. The results were of comparable accuracy and reproducibility with those of the reported methods

Spectrophotometric determination of azidoamphenicol in pure form and in combination with other drugs

Two sensitive and simple spectrophotometric methods have been developed for the determination of azidoamphenicol. The first method depended simply on measuring the UV absorbance of the pure drug in methanol at 273 nm. The second method was based on the formation of a yellow Schiff's base [lambda max = 393 nm] between azidoamphenicol and 10% w/v vanillin in methanol, after reduction of NO2 group with zinc dust and sulfuric acid. Analysis of Beer's plot showed good regression in the concentration range of 5-30 and 2-8 mug/ml for the UV and Schiff's base method, respectively. Schiff's base method has been applied for the analysis of the studied drug in pure form and in Baycuten cream in the presence of clotrimazole and dexamethasone acetate. High percentage recoveries resulted from the analysis of laboratory synthetic mixture, prepared in the same ratio as the commercial cream. This indicated the absence of interference from other combined drugs and the selectivity of Schiff's base method

Quantitation of floctafenine by high pressure liquid chromatography [HPLC] and spectrophotometric methods

Two methods for the quantitative determination of floctafenine are described. The first, a spectrophotometric procedure, is based on the formation of a red Schiff-base between floctafenine and p- dimethylaminocinnamaldehyde [p-DAC] after reduction with zinc powder and hydrochloric acid in ethanol acidic medium at room temperature. At the maximum absorption of 541 nm, Beer-Lambert's Law was adhered to over the 1-9 mug/ml range [epsilon max 3.99 x 10 4 l/mol/cm]. The second method involved the application of HPLC, C-18 column, with a mobile phase consisting of 82.5: 17.5 methanol: water at a flow rate of 1 ml/min. Samples dissolved in methanol were estimated by the measurement of peak height using UV detection at 254 nm. The results obtained with the two proposed methods revealed their successful application for the quantitative estimation of floctafenine in bulk drug and as tablets with good accuracy and precision