Pharmacokinetics Of Sulphadimidine In Non-Starved And Starved Male Turkeys

Measurement of drug concentrations in the blood and urine are performed to determine the need for adjustment of the dosage or schedule of administration. Since sulphadimidine is used in the treatment of infectious diseases caused by Gram positive and negative bacteria and coccidia which can cause anorexia leading to starvation in turkeys, there is need to study pharmacokinetics of sulphadimidine in non-starved and starved costlier male turkeys. Twenty male turkeys of 12 weeks old and weighing 1.77±0.03kg were divided into two groups of ten each. One group was administered a single intramuscular dose of 100mg/kg body weight of sulphadimidine. The other group was kept off-feed for 48hours before administration of 100mg/kg body weight intramuscular sulphadimidine. The findings revealed that the concentration maximum (Cmax=103.06±2.80 µg/ml), time of maximum drug concentration (Tmax=1.40±0.10 hr), absorption rate constant (α=0.61±0.10 hr-1), absorption half-life (t1/2α=1.60±0.36 hr), elimination rate constant (β= 0.095±0.01 hr-1), elimination half-life (t1/2β=7.62±0.51 hr), body clearance (Clb=0.12±0.010 L/kg/hr), mean residence time (MRT=10.96±0.74 hr), area under the curve from zero to 96hours (AUC0-96=1.60±0.10 mg/L/hr), area under the curve from zero to infinity (AUC0-∞=1.61±0.10mg/L/hr), area under moment curve (AUMC=17.76±1.80 mg/L), and volume of distribution of central compartment(Vc= 1.72±0.05 L/kg) were significantly lower (p<0.05) in non-starved turkeys in comaparism with the Cmax(131.38±9.74µg/ml), Tmax(1.85±0.08 hr), α(0.33±0.04 hr-1), t1/2α(2.45±0.31 hr), β(0.062±0.01 hr-1), t1/2β(12.76±1.52 hr), Clb(0.071±0.00 L/kg/hr), MRT(18.18±2.09 hr), AUC0-96(2.65±0.20 mg/L/hr), AUC0-∞(2.70±0.21mg/L/hr), AUMC(50.72±8.37 mg/l), and Vc(1.43±0.11 L/kg) of the starved turkeys. In conclusion, 100mg/kg body weight of intramuscular sulphadimidine needs adjustment in starved male turkeys and may likely be accumulated in tissues over a relatively long period of time.

Fig.1: Mean serum concentration-time curve of sulphadimidine (100mg/kg) following a single intramuscular administration to non starved and starved male turkeys (n=10).