Spectrophotometric determination of acrivastine in urine and capsules

Three sensitive and accurate spectrophotometric methods are presented for the determination of the antihistaminic acrivastine (ACR) in capsules and urine. The first method utilizes the reaction of 2-nitrophenylhydrazine hydrochloride in presence of dicyclohexylcarbodiimide and pyridine. The violet colour of the resulting acid hydrazide is measured at 550 nm. The second method is based on alkaline oxidation of the drug with potassium permanganate and subsequent measurement of the formed manganate ion at 608 nm. The third method uses derivative spectrophotometry for the determination of ACR. The last method is extended to the in vitro determination of the drug in urine. All methods gave a relative standard deviation of less than 2%.     

Densitometric Kinetic Stability Studies of Some Plant Extracts Using Different Regression Methods

JPC – Journal of Planar Chromatography – Modern TLC -     

Spectrophotometric Determination of Ternary Mixtures by the Derivative Ratio Spectrum-Zero Crossing Method

Abstract

A new spectrophotometric method is introduced for the assay of ternary mixtures with overlapping spectra. The method is based on the use of the first derivative of the ratio spectra and measurements of zero-crossing wavelengths. The ratio spectra were obtained by dividing the absorption spectrum of the mixture by that of one of the components. The concentration of the other components are then determined from their respective calibration graphs treated similarly. The method has been applied for the resolution of two ternary mixtures, namely, dipyridamole, aspirin and salicylic acid (I) and dipyridamole, oxazepam and 2-amino-5-chlorobenzophenone (II). Salicylic acid and benzo-phenone derivative are the degradation products of aspirin and oxazepam, respectively. The proposed method was applied for the assay of these combinations in synthetic mixtures and in commercial dosage forms. The results obtained were precise and accurate.