ITRACONAZOLE PLASMA AND TISSUE CONCENTRATIONS IN THE SPINY LIZARD (SCELOPORUS SP) FOLLOWING ONCE-DAILY DOSING

Mycotic infections in reptiles present as primary diseases and as seco ndary problems in healing wounds and immunocompromised animals. A tria zole antimycotic drug, itraconazole is orally active and well distribu ted and is effective against many common fungal pathogens in humans. T o assess plasma and tissue concentrations after oral dosing in reptile s, a 23.5-mg/kg (mean) itraconazole dose was administered orally with a standard food bolus once daily for 3 days to 10 groups of three or f our spiny lizards (Sceloporus sp.). On days 0, 1, 2, 3, 4, 6, 9, 12, a nd 18, group samples of blood, liver, and muscle were collected. Micro biologic assay of itraconazole concentrations was performed on these p ooled samples. Values from an elimination graph of the concentrations of area under the curve (377.21 mu g.hr/ml) and terminal elimination h alf-life (48.3 hr) were obtained for itraconazole in spiny lizard plas ma. Peak itraconazole concentration of 2.48 mu g/ml was obtained in tw o half-lives and would be expected to achieve steady state at approxim ately 3.1 mu g/ml plasma concentration in 10 days. Peak liver concentr ation of 4.27 mu g/ml was attained in 89.95 hr. Muscle concentration d id not exceed 0.63 mu g/ml and declined by 97.3 hr. With this dosing r egimen, itraconazole plasma and liver concentrations would persist wit hin reported minimum inhibitory concentrations for many fungal pathoge ns for 6 days beyond the peak concentration.