Abstract

Electrochemical behaviour of dexamethasone at the fullerene-C₆₀-modified pyrolytic graphite electrode (PGE) has been investigated using Osteryoung square wave voltammetry (SWV). Compared to a bare PGE and fullerene-C₆₀-modified glassy carbon electrode (GCE), the fullerene-C₆₀-modified edge plane PGE exhibited an apparent shift of the peak potential to less negative potentials with a marked enhancement in the current response of dexamethasone. The peak potential was linearly dependent on pH with dE_p/dpH as 59 mV/pH. Calibration plot having good linearity with a correlation coefficient 0.9983 is obtained in the concentration range of 0.05–100 μM and the sensitivity of the method has been found to be 0.685 μA μM⁻¹. The detection limit is estimated to be 5.5 × 10⁻⁸ M. The electrode showed good sensitivity, stability and reproducibility. The practical analytical utility of the method is illustrated by quantitative determination of dexamethasone in several commercially available pharmaceutical formulations and human blood plasma of patients being treated with dexamethasone. HPLC method was used to compare the results obtained for the quantitative estimation of dexamethasone in biological fluids.

Keywords: Fullerene-C₆₀-modified pyrolytic graphite electrode; Dexamethasone; Blood plasma; Doping; Square wave voltammetry

Article Outline

1. Introduction

2. Materials and methods

2.1. Apparatus

2.2. Reagents

2.3. Procedure

2.4. Fabrication of fullerene-C₆₀-modified pyrolytic graphite electrode and glassy carbon electrode

3. Results and discussion

3.1. Voltammetric reduction of dexamethasone

3.2. Effect of Osteryoung square wave parameters

3.3. Effect of pH

3.4. Concentration study

3.5. Stability and reproducibility of the modified electrode

3.6. Analysis of commercial samples

3.7. Real sample analysis

3.8. Methods comparison

4. Conclusions

Acknowledgements

References