Differential pulse voltammetric determination of methylprednisolone in pharmaceuticals and human biological fluids

Electrochemical behaviour of methylprednisolone (MP) at the fullerene-C60-modified glassy carbon electrode has been investigated using differential pulse voltammetry. The experimental results suggest that the modified electrode exhibits electrocatalytic effect on the oxidation of MP resulting in a marked enhancement of the peak current response. Under the selected conditions, the oxidation peak current was linearly dependent on the concentration of MP in the range 5.0 nM–1.0 μM with a sensitivity of 0.0107 μA μM−1. The detection limit was estimated to be 5.6 nM. The electrode showed good sensitivity, selectivity, stability and reproducibility. In addition, the developed method was satisfactorily applied to the determination of MP in pharmaceutical formulations and human serum and urine samples without any necessity for sample treatment or time-consuming extraction steps prior to the analysis. GC–MS method was used to cross-validate the results obtained for the quantitative estimation of MP in biological fluids and the results showed ∼2% deviation to those obtained using the proposed method.