Determination of diltiazem based on the reduction of Cu(II)–BCA complexes in micellar medium

Abstract

A simple method was developed for determining microquantities of diltiazem, based on the reduction of copper(II) in buffered solution (pH 7.0) and the use of a micellar medium containing 4,4'-dicarboxy-2,2'-biquinoline acid. The copper(I) produced reacts with 4,4'-dicarboxy-2,2'-biquinoline acid and the complexes formed are spectrophotometrically measured at 558 nm. A typical calibration graph shows good linearity (r = 0.993) from 20 to 100 mg mL -1 of diltiazem. The limit of detection and relative standard deviation were calculated as 12 mg mL -1 (99% confidence level) and 3.5% (40 mg mL -1 ; n = 6), respectively, with a mean recovery value of 96.5% found in pharmaceutical dosages. A straightforward and effective way to recycle the reagents is addressed. The hazardous aspects of the Cu(I)-BCA reaction are presented as well.Résumé : On a développé une méthode simple pour déterminer des microquantités de diltiazem basée sur la réduction du cuivre(II), dans une solution tamponnée (pH de 7,0) et un milieu micellaire contenant de la 4,4'dicarboxy-2,2'-biquinoléine. Le cuivre(I) qui est produit réagit avec l'acide 4,4'-dicarboxy-2,2'-biquinoléine et les complexes qui se forment peuvent être mesurés d'une façon spectrophotométrique à 558 nm. Un graphique de calibration typique présente une bonne linéarité (r = 0 093) pour des concentrations allant de 20 à 100 mg mL -1 de diltiazem. On a calculé que la limite de détection et la déviation standard relative sont respectivement égales à 12 mg mL -1 (niveau de confiance de 99 %) et de 3,5 % (40 mg mL -1 ; n = 6) avec une valeur moyenne de récupération de 96,5 % des dosages présents dans des formulations pharmaceutiques. On présente les risques associés à l'utilisation de la réaction Cu(I)/ABC ainsi qu'une méthode simple et efficace de recycler les réactifs utilisés.

An Overview of Analytical Determination of Diltiazem, Cimetidine, Ranitidine, and Famotidine by UV Spectrophotometry and HPLC Technique

“…Assay was performed by the firstand second-order method with the application of "peakzero" and "peak-peak" techniques with excellent correlation coefficient ( 2 < 0.9999). Sabino et al [34] presented a very sensitive determination of diltiazem by the reduction of Cu(II) in buffer (pH 7) and micellar medium be full of 4,4dicarboxy-2,2 biquinoline acid. Cu(I) produced as a result of reduction of Cu(II) reacts with 4,4-dicarboxy-2,2 biquinoline acid-formed complexes which was quantitatively detected at 558 nm.…”

Sistema de análises em fluxo polivalente para a determinação espectrofotométrica de fármacos

“…Apesar de resultados distintos terem sido obtidos para cada fármaco, a melhor resposta, considerando o sinal analítico e a reprodutibilidade, foi obtida em pH 7,0, no qual o sistema tampão apresenta sua maior capacidade tamponante. Este pH coincide com o empregado em estudos anteriores, [13][14][15][16][17] exceto no caso da determinação de proteínas. 12 O comprimento do reator afeta tanto o tempo de residência, quanto a dispersão da amostra.…”

Metal-to-Ligand Charge-Transfer-based Visual Detection of Alkaline Phosphatase Activity

“…The LOD of ALP is 1.27 mU mL -1 and the dynamic range is 0 -200 mU mL -1 . 27 This method is simple and efficient with high selectivity and interference immunity. Hence, the MLCTbased method of ALP activity has great potential and wide application to study.…”