N-hydroxy-N'-(4-n-butyl-2-methylphenyl)formamidine (
HET0016) is a potent inhibitor of
20-hydroxyeicosatetraenoic acid (20-HETE) formation by specific
cytochrome P450 isoforms. Previous studies have demonstrated that administration of
HET0016 inhibits brain formation of
20-HETE and reduces brain damage in a rat model of thromboembolic
stroke. Delineation of the dose, concentration, and
neuroprotective effect relationship of
HET0016 has been hampered by the relative insolubility of
HET0016 in aqueous solutions and the lack of information concerning the mechanism and duration of
HET0016 inhibition of brain
20-HETE formation. Therefore, it was the purpose of this study to develop a water-soluble formulation of
HET0016 suitable for intravenous (i.v.) administration and to determine the time course and mechanism of brain
20-HETE inhibition after in vivo dosing. In this study we report that
HET0016 is a noncompetitive inhibitor of rat brain
20-HETE formation, which demonstrates a tissue concentration range for brain inhibition. In addition, we demonstrate that complexation of
HET0016 with
hydroxypropyl-beta-cyclodextrin results in increased aqueous solubility of
HET0016 from 34.2 +/- 31.2 to 452.7 +/- 63.3 microg/ml. Administration of the complex as a single
HET0016 i.v. dose (1 mg/kg) rapidly reduced rat brain
20-HETE concentrations from 289 to 91 pmol/g. Collectively, these data demonstrate that the i.v. formulation of
HET0016 rapidly penetrates the rat brain and significantly inhibits
20-HETE tissue concentrations. These results will enable future studies to determine biopharmaceutics of
HET0016 for inhibition of
20-HETE after
cerebral ischemia.