Determination of the Antiviral Drug Oseltamivir (Tamiflu) by Adsorptive Stripping Voltammetry

This paper describes a stripping method for the determination of oseltamivir (Tamiflu) at the submicromolar concentration level. This method is based on controlled adsorptive accumulation of oseltamivir at the thin-film mercury electrode followed by a linear cyclic scan voltammetry measurement of the surface species. Optimum experimental conditions consist of a NaOH solution (pH 7-8) as supporting electrolyte, an accumulation potential of -0.40 V, and a scan rate of 100 mV s-1. The response of oseltamivir is linear over the concentration range from 0.0 - 0.5 ppm using lower accumulation time. When there was an accumulation time of 15 minutes, the detection limit was found to be 1.66 ppb (5.3 x 10-9 mol L-1). More convenient methods to measure the oseltamivir in the presence of the didanosine, acyclovir, nevirapine, nelfinavir, efavirenz, lamivudine and zidovudine were also investigated in this experiment. The utility of the method is demonstrated by the presence of oseltamivir together with hypoxanthine, ATP or DNA.