Electrochemical investigation and liquid chromatographic analysis of triamcinolone acetonide in pharmaceutical formulations

Abstract

Electrochemical reduction of triamcinolone acetonide on pencil graphite electrode surface was firstly investigated by cyclic voltammetry (CV). The dependence of cathodic peak current and peak potential on different pH medium and scan rate were investigated. The adsorption controlled nature of the peak was achieved. During pH optimization, 0.067 M Phosphate (pH 4.50 to pH 7.50), 0.2 M Acetate (pH 3.50 to 5.50) and 0.04 M Britton Robinson (BR; pH 2.00 to 12.00) buffers were employed as supporting electrolytes. Scan rate optimization was investigated in the range 25-1000 mVs-1 (vs. Ag/AgCl). Maximum peak current was observed in the 0.04 M BR buffer (pH 3.50). Peak current increases and shifts to more cathodic values with the increasing scan rate. Curve of logarithm of peak current (log I) versus logarithm of scan rate (log v) showed linear regression with the equation log(Ip/μA) = 0.8395 log(v/mVs-1)-0.8386 and correlation coefficient (R2: 0.9761). This indicated that slope of the logv-logI curve is close to 1.0 and the cathodic electrode reaction was adsorption controlled, as desirable. The linear range was 1×10-7-5×10-5 M, sensitivity was 1,3347 µA M-1, Limit of detection (LOD) and Limit of quantification (LOQ) were 3.18×10-8 M and 1.00×10-7 M, respectively. HPLC-PDA analysis were performed with H2O:MeOH (28:72, v/v) as mobile phases A and B at a flow rate of 1mL/min at 242nm. Method validation studies were conducted in accordance with ICH Q2(R1) guideline and corresponding results were summarized in tables. HPLC-PDA method displayed linearity in 0.1-50µg/mL (2.3×10-7-1.15×10-4 M) concentration range with LOD and LOQ values as 3.992×10-8 and 1.29×10-7M, respectively.