Spectrophotometric determination of ethionamide in pharmaceuticals using Folin–Ciocalteu reagent and iron(III)-ferricyanide as chromogenic agents

Abstract

Two simple and sensitive spectrophotometric methods are described for the determination of ethionamide (ETM) in pure drug and tablets. The first method is based on the reduction of Folin-Ciocalteu (F-C) reagent by ETM in sodium carbonate medium to form a blue coloured complex, which was measured at 760 nm (Molybdenum-tungsten blue method). In the second method (Prussian blue method), iron(III) was reduced to iron(II) by ETM in HCl medium, in which iron(II) was complexed with ferricyanide, and the resulting Prussian blue was also measured at 760 nm. The absorbance measured in each case was related to the ETM concentration. The experimental conditions were carefully studied and optimised. Beer's law was obeyed in concentration ranges of 1-40 g/ml and 0.2-4.0 g/ml with the Molybdenum-tungsten blue method and the Prussian blue method, respectively, with corresponding molar absorptivity values of 5.72 × 10 3 and 3.18 × 10 4 l/(mol•cm). The limits of detection (LOD) and quantification (LOQ) were 0.09 and 0.27 g/ml for the Molybdenum-tungsten blue method and 0.01 and 0.04 g/ml for the Prussian blue method. Within-day and between-day relative standard deviations (%RSD) at three different concentration levels were <3%, and the respective relative errors (%RE) were ≤2%, implying good accuracy and precision of the methods. The proposed methods were successfully applied to the determination of ETM in bulk powder and tablets, and the results demonstrated that the methods were as accurate and precise as the official method.

Spectrophotometric/Titrimetric Drug Analysis

“…However, these methods require the drug to be present in the base or acid forms for complexation. For example, typical, some methods based on extractive spectrophotometric are used for the determination of some formulations after selecting the optimum conditions by preliminary experiments, such as pH, buffer, and solvent; at the wavelength of maximum absorption; (a) bromocresol purple used for terbinafine [21,24], nifedipine [50], sulfadimidine, sulfaguanidine, sulfametrole, sulfaquinoxaline, and sulfamethoxazole [51], hydroxyzine dihydrochloride [52], lercanidipine [53], oxomemazine hydrochloride [54], and atorvastatin [55].…”

“…If we follow the international refereed journals that are concerned with publishing scientific research in the field of drug analysis, we will find that the majority of published research has used the spectrophotometric technique in analysis, directly or indirectly. To name a few, in the estimation of some anti-infective agents in pharmaceuticals, we will find that most of the published research about it used spectroscopic methods [21][22][23][24][25][26][27][28][29][30]. We also find that browsing through the majority of pharmaceutical analysis books finds that all of them give more space in that books to talk about spectrophotometric techniques and their various applications, especially in the field of drug analysis.…”

Design of imprinting matrix for dual template sensing via electropolymerized polythiophene films

“…Both AnP and ETH have been individually detected via many chemical analysis methods such as spectrophotometric methods, gas liquid chromatography (GLC), high-performance liquid chromatography (HPLC) and fluorometry. [25][26][27][28][29][30][31] However, compared with these methods, the electrochemical methods are of low cost, facile, rapid methodology, real time results, sensitive and environment friendly. [32][33][34] Furthermore, molecular imprinting is advantageous due to high selectivity, negligible matrix effect, high adsorption performance, good stability, and reusability.…”

“…Both AnP and ETH have been individually detected via many chemical analysis methods such as spectrophotometric methods, gas liquid chromatography (GLC), high‐performance liquid chromatography (HPLC) and fluorometry 25‐31 . However, compared with these methods, the electrochemical methods are of low cost, facile, rapid methodology, real time results, sensitive and environment friendly 32‐34 .…”

Graphene oxide-based electrochemical activation of ethionamide towards enhanced biological activity

“…8 Considering the above mentioned side effects, researchers have developed various analytical tools for the determination and quantication of ETO from various formulations and even real samples. [9][10][11][12][13][14][15] For example, Sujitkumar et al reported a UV-Vis spectrophotometric method for ETO estimation from bulk and tablets. 10 Madni et al gave an account of an HPLC method for the determination of ETO from serum.…”