Voltammetric determination of praziquantel in tablets and biological fluids

A simple method is described for the determination of praziquantel (CAS 552 68-74-1) in Its pure form, tablet formulations and biological fluids. The p roposed method depends upon the polarographic activity of praziquantel at t he dropping mercury electrode (DME) in Britton Robinson buffers, whereby a well-defined catholic wave Is produced over the pH range 7-12. The wave was characterized as being irreversible diffusion-controlled with limited adso rption properties. The diffusion current constant (Id) was 0.56 +/- 0.004 ( n = 11). The current-concentration relationship was found to be rectilinear over the range 8-48, 3.2-38.4 and 0.48-20 mug . ml(-1) using direct curren t (DCt), differential pulse polarographic (DPP) and alternating current (AC (t)) odes, respectively, with minimum detection limit (S/N = 2) of 0.32 mug . - ml(-1) (1.02 X 10(-6) mol/l and 0.02 mug . ml(-1) (6.4 X 10(-8) mol/l) for DPP and AC, modes respectively. The average percent recovery was favou rably compared to a reference method with a satisfactory standard deviation . The proposed method was applied to spiked human urine and plasma. The per centage recoveries were 99.33 +/- 0.79 and 98.23 +/- 0.53, respectively.