Proposal of open field test as a model of varenicline pharmacokinetic study in rats

Abstract

Varenicline is a medication used for smoking treatment that acts as a partial agonist for nicotinic cholinergic receptors α4β2 and α3β4 and as a total agonist of receptor α7 in the central nervous system. Pharmacokinetic is important information for medications that acts in the central nervous system. This kind of assay is commonly done by expensive and complex analytical techniques. Therefore, the aim of this study was to evaluate the possibility of using the open field test as a pharmacokinetic model for varenicline in male rats exposed to a single dose of varenicline. Male rats received a single dose orally (gavage) of three different concentrations of varenicline: 0.03 (therapeutic dose for humans), 0.1 and 0.3 mg/kg or water (control group). The open field observations were recorded 30 min, 1, 2, 4, 6, 24, 48, 72 h and 7 days after the administration of varenicline or water. The results showed alterations in locomotion and rearing frequencies, as well as in immobility time observed in open field, which is consistent with this drug’s plasma peak. Consequently, this behavioral test apparently can be considerate as a model for pharmacokinetic evaluation of varenicline.