An improved HPLC method for determination of nifuratel in human plasma and its application to pharmacokinetics studies

A rapid, simple and sensitive high-performance liquid chromatography (HPLC) method was established for the quantification of nifuratel in human plasma and applied to a study of its pharmacokinetics. A test and a reference formulation were investigated and compared, and the study group consisted of 24 healthy male volunteers. The analytical technique was based on a single extraction of the drug from the plasma with chloroform, using ornidazole as internal standard (IS). The chromatographic system consisted of a 5-μm 4.6 mmX250 mm C18 analytical column and the mobile phase consisted of methanol and purified water (45∶55, v/v). Nifuratel and ornidazole concentrations were detected by ultraviolet (UV) absorbance at a wavelength of 254 nm. The lower limit of detection and quantification was 0.5 ng·ml−1, and the calibration curves were linear over a concentration range of 0.5–160 ng·ml1 nifuratel in the plasma. The results showed that the area under the plasma concentration-time curve (AUC), time to maximum observed plasma concentration (Tmax), maximum concentration reached in the concentration profile (Cmax), and elimination half-life (t1/2) between the test tablets and the reference tablets demonstrated no significant difference (P>0.05). The relative bioavailability amounted to 103.13% ± 8.73%.