Kinetic spectrophotometric methods for the determination of dothiepin hydrochloride in bulk and in drug formulation

Abstract

Two simple and sensitive kinetic methods for the determination of dothiepin hydrochloride are described. The first method is based on kinetic investigation of the oxidation reaction of the drug with alkaline potassium permanganate at room temperature for a fixed time of 25 min. The absorbance of the colored manganate ions is measured at 610 nm. The second method is based on the reaction of dothiepin hydrochloride with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in the presence of 0.1 mol L(-1) sodium bicarbonate. Spectrophotometric measurement was achieved by recording the absorbance at 470 nm for a fixed time of 60 min. All variables affecting the development of the color were investigated and the conditions were optimized. Plots of absorbance against concentration in both procedures were rectilinear over the ranges 4-24 and 50-250 microg mL(-1), with mean recoveries 99.33+/-0.42 and 99.88+/-0.53, respectively. The proposed methods were successfully applied for the determination of dothiepin hydrochloride in bulk powder and in capsule dosage form. The results obtained were found to agree statistically with those given by the non-aqueous B.P. method. Furthermore the methods were validated according to USP guidelines and also assessed by applying the standard addition technique. The determination of dothiepin hydrochloride by the fixed concentration method is feasible with the calibration equations obtained, but the fixed time method proves to be more applicable.

Spectrofluorimetric and Spectrophotometric Stability-Indicating Methods for Determination of Some Oxicams Using 7-Chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl)

“…NBD derivatives are usually determined fluorimetrically, 29,30) however, photometric detection has also occasionally been used. 31,32) The aim of this study was to optimize the reaction between the alkaline hydrolytic products of the three studied drugs and NBD-Cl.…”

Application of 4-chloro-7-nitrobenzofurazan for the analysis of propafenone and diltiazem hydrochlorides using kinetic spectrophotometric and spectrofluorimetric methods

“…NBD-Cl was also applied for the kinetic determination of clindamycin phosphate [56], tramadol hydrochloride [57], dothiepin hydrochloride [58], trimetazidinedihydrochloride [59], befunolol hydrochloride [60], isoxsuprine [61], ciprofloxacin hydrochloride, norfloxacin [62], acetylcysteine, carbocisteine [63], fluvastatin [64], betahistinedihydrochloride and etilefrine hydrochloride [65]. In this work, spectrophotometric, spectrofluorimetric methods were developed for the determination of propafenone HCl and diltiazem HCl using NBD-Cl accompanied with kinetic study.…”

Extractive Colorimetric Method for the Determination of Dothiepin Hydrochloride and Risperidone in Pure and in Dosage Forms

“…Several methods have been reported for its determination, including derivative, 2) extractive colorimetric ion pair complex formation, 3) kinetic spectrophotometry using alkaline potassium permanganate or 4-chloro-7-nitrobenzofurazon, 4) charge transfer, and ion-associate complex formation. 5,6) Other techniques such as HPLC, 7,8) GC, 9) voltammetry, 10) and RIA 11) were also reported for dothiepin analyses.…”