Comparative pharmacokinetics of piroxicam in male and female West African Dwarf goats

Piroxicam is an anti-inflammatory, analgesic and antipyretic drug. It is presently used for postoperative pain management in ruminants. However, female animals have been reported to be more sensitive to piroxicam. Hence its pharmacokinetic parameters were investigated in West African Dwarf (WAD) goats. Ten goats divided into two groups, each comprised five females and five males were administered piroxicam at predetermined dose of 5 mg/kg body weight via thigh muscle. The blood samples were collected into EDTA bottles before the treatment and thereafter at 0.08, 0.16, 0.25, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 24, 48, 72, 96, 120, 144, 168, and 192 h for analysis of piroxicam using a spectrophotometric method at 330 nm wavelength. Concentration maximum (Cmax = 543.2 ± 64.4 μg/ml), absorption rate constant (α = 1.2 ± 0.4 h), and elimination rate constant (β = 0.4 ± 0.2 h of the male WAD goats were significantly higher (p < 0.05) in comparison with Cmax (376.9 ± 61.2 μg/ml), α (0.8 ± 0.3 h) and β (0.3 ± 0.1 h) of the female WAD goats, respectively. The absorption half life (t1/2α = 1.6 ± 0.6 h), elimination half life (t1/2β = 5.2 ± 2.3 h), body clearance (Clb = 1.1 ± 0.2 L/kg/h), mean residence time (MRT = 7.8 ± 3.5 h) and mean absorption time (MAT = 1.8 ± 0.4 h) of the female WAD goats were significantly higher (p < 0.05) in comparison with t1/2α (0.9 ± 0.3 h), t1/2β (2.5 ± 0.6 h), Clb (0.4 ± 0.1L/kg/h), MRT (0.9 ± 0.6 h) and MAT (1.3 ± 0.5 h) of the male goats respectively. The percentage protein binding capacity in the species was 81.9%. But three out of five female goats were paralyzed. Hence female WAD goats may be more sensitive to piroxicam than male WAD goats