Voltammetric quantification of anti-hepatitis drug Adefovir in biological matrix and pharmaceutical formulation

Electrochemical reduction behavior of Adefovir was studied using Hanging Mercury Drop Electrode (HMDE) in Britton-Robinson (BR) buffer solution. Voltammetric study showed one well-defined reduction peak in the potential range -1.2 to -1.4 V (vs. Ag/AgCl) due to reduction of C=N bond of the imidazole ring. Solid-phase extraction and protein-precipitation techniques were employed for extraction of Adefovir from human plasma. The proposed method allows quantification of Adefovir in human plasma over the concentration range 0.50-5.00 μg/mL with the detection limit 0.17 μg/mL, whereas in pharmaceutical formulation 0.25-2.25 μg/mL with the detection limit 0.08 μg/mL.