Pharmacokinetics of oxytetracycline in the American horseshoe crab, Limulus polyphemus

The American horseshoe crab, Limulus polyphemus, is regularly cultured and maintained in research laboratories and public aquaria. Rising concerns over the health of these captive animals makes the diagnosis and treatment of pathological conditions in L. polyphemus essential. This study investigated the kinetics of oxytetracyline following either intravascular or oral dosing. Oxytetracylcine is a broad-spectrum antibiotic used in the treatment of various bacterial diseases of aquatic animals. A noncompartmental model was developed to describe the pharmacokinetics of oxytetracycline (OTC) in the horseshoe crab. The following parameters were determined for a single intravascular bolus of 25 mg/kg OTC: AUC = 9524.60 mu g.h/mL, MRT = 443.65 h, Cl-b = 0.044 mL/min/kg, V-d(ss) = 1.164 L/kg, t(1/2) = 128.3 h, C-max = 55.90 mu g/mL, C-ave = 27.39 mu g/mL. Following a single oral bolus of 25 mg/kg, these parameters were calculated: AUC = 5861.81 mu g.h/mL, MRT = 395.89 h, Cl-b = 0.071 mL/min/kg, V-d(ss) = 1.688 L/kg, t(1/2) = 210.0 h, C-max = 7.83 mu g/mL, C-ave = 2.89 mu g/mL, F = 61.56%.