ABSTRACT
A highly sensitive and selective HPLC-MS/MS method is presented for the quantitative determination of tiloronoxim and its metabolite tilorone in human blood. An aliquot of 200 microl human blood was extracted with a mixture of chloroform/ethyl ether (1/2, v/v), using metoprolol as the internal standard (the IS). Separation was achieved on an Xterra MS C18 column (50 mm x 2.1 mm, 5 microm) with a gradient mobile phase of methanol/water containing 15 mM ammonium bicarbonate (pH 10.5). Detection was performed using positive MRM mode on a TurboIonSpray source. The mass transitions monitored were m/z 426.3-->100.0, m/z 411.3-->100.0 and m/z 268.3-->116.1 for tiloronoxim, tilorone and the IS, respectively. The method was fully validated using total error theory, which is based on beta-expectation tolerance intervals and include trueness and intermediate precision. The method was found to be accurate over a concentration range of 1-100 ng/ml for both compounds. The measurement uncertainty based on beta-expectation tolerance intervals was assessed at each concentration level of the validation standards. This method was successively applied to a pharmacokinetic study of tiloronoxim in healthy volunteers.
Subject(s)
Antiviral Agents/blood , Antiviral Agents/pharmacokinetics , Chromatography, High Pressure Liquid/methods , Mass Spectrometry/methods , Oximes/blood , Oximes/pharmacokinetics , Tilorone/analogs & derivatives , Uncertainty , Antiviral Agents/administration & dosage , Drug Stability , Humans , Limit of Detection , Oximes/administration & dosage , Regression Analysis , Reproducibility of Results , Tilorone/administration & dosage , Tilorone/blood , Tilorone/pharmacokinetics , Time FactorsABSTRACT
1. The hepatic disposition of tilorone HCl, an antiviral and antitumour agent, was studied in male Wistar rats after intraduodenal administration. 2. A concentrative transfer into the liver occurred, the liver/portal blood concentration ratio being 120 or higher. The relationship between dose and hepatic concentration was linear. 3. Biliary excretion of tilorone was low and dose-related; whole blood concentration was also dose-related. 4. Neither hepatic concentration nor biliary excretion exhibited saturation over the dosage studied (6--174 mg/kg). The hepatic 'depot' of tilorone lacked the characteristics of a true 'first-pass' effect.
