Pharmacokinetics of demeclocycline and doxycycline after intramuscular administration in goat

Abstract

Pharmacokinetic study of demeclocycline and doxycycline was carried out separately for each drug after a single i/m
dose of 5 mg/kg in 6 healthy goats. Peak plasma concentrations of 2.35+-0.17 and 1.47±0.17 ug/ml were attained at 6 and 1 hr while therapeutic concentration of >- 0.5 ug/ml maintained from 30 min to 36 hr and 15 min to 2 hr for demeclocycline and doxycycline, respectively. The absorption half life (ty₂ Ka), of doxycycline was observed of demeclocycline and doxycycline. Significantly higher values of Vd_area and CI_B were obtained for doxycycline as compared to demeclocycline. The calculated loading dose (0*) and maintenance dose (D_O) were significantly higher for doxycycline for maintaining MIC of 0.5 and 1.0 ug/ml at the dosage interval of 12 and 24 hr as compared to demeclocycline.