The effect of experimental fascioliasis on the pharmacokinetics of antipyrine and sulphadimidine in desert sheep

Healthy adult male desert sheep were experimentally infected with Fasciola gigantica, to investigate the influence of experimental fasciolasis on the pharmacokinetics of antipyrine and sulphadimidine. Each animal received 500 metacercariae orally. The experimental infection was confirmed histologically, by detection of Fasciola eggs in faeces and by measuring the activities of the enzymes sorbitol dehydrogenase (SD), glutamate dehydrogenase (GD) and aspartate aminotransferase (AST) in plasma during the course of the disease. Changes in the pharmacokinetics of antipyrine and sulphadimidine were reported in the experimentally infected animals. Significant prolongation of antipyrine half life was observed 16 weeks after infection. The half-life of sulphadimidine was also significantly prolonged 5, 9 and 16 weeks after infection. Clearance of the sulphonamide was decreased significantly 5 and 9 weeks after infection and it regained its pre-infection value 16 weeks after infection

The effect of water deprivation on the pharmacokinetics of antipyrine and sulphadimidine following intravenous administration in Nubian goats

The effect of water deprivation on the pharmacokinetic parameters of antipyrine and sulphadimidine in the Nubian goat was studied. Water deprivation, to a level of dehydration at which the animals lost an average of 7.5% body weight, resulted in a significant reduction in antipyrine clearance (p < 0.05), and a consequently increased AUC value (p < 0.05). No effect was observed on the distribution parameters of the drug. In dehydrated animals which had lost an average of 10% or 12.5% of their body weight owing to water deprivation, significant changes were found in the distribution and elimination pharmacokinetic parameters of antipyrine and sulphadimidine. The volume of distribution was significantly decreased, resulting n elevated plasma levels for the two drags compared to normally watered animals. Significant decreases in clearance and subsequent prolongation of the elimination half-lives were observed during these periods of water deprivation. These changes in the disposition kinetics of the two drugs may be attributed to the loss of total body water and extracellular fluids and changes in the liver and kidney functions taking place during dehydration

Comparative pharmacokinetics of ampicillin trihydrate, gentamicin sulphate and oxytetracycline hydrochloride in Nubian goats and desert sheep

In this investigation the pharmacokinetics of three commonly used antibiotics, ampicillin trihydrate (10 mg/kg), gentamicin sulphate (3 mg/kg) and oxytetracycline hydrochloride (5 mg/kg), given intravenously, were each studied in five Nubian goats and five desert sheep. The pharmacokinetic parameters were described by a two-compartment open model. The results indicated that there were significant differences between the two species in some kinetic parameters of ampicillin and oxytetracycline but not gentamicin. Ampicillin elimination half life (t1/2β) in goats (1.20 h) was shorter than that in sheep (2.48 h), and its clearance (Cl) significantly higher in goats (2921mL/h·kg) compared to sheep (262 mL/h·kg) (P < 0.01). Ampicillin volume of distribution (Vdarea) was found to be significantly larger in goats (5673 mL/kg) than in sheep (992 mL/kg) (P < 0.01). For oxytetracycline, the t1/2β in goats (3.89 h) was significantly shorter than that in sheep (6.30 h) and the Cl value in goats (437 mL/h·kg) was significantly higher than in sheep (281 mL/h·kg). The results suggest that when treating sheep and goats, the pharmacokinetic differences between the two species must be considered in order to optimize the therapeutic doses of ampicillin and oxytetracycline

Effect of dehydration on the pharmacokinetics of oxytetracycline hydrochloride administered intravenously in goats (Capra hircus)

1. The effects of various levels of dehydration induced by water deprivation were studied in six Nubian goats on the pharmacokinetics of oxytetracycline after intravenous administration (5 mg/kg). 2. In goats that had lost an average of 7.6% body weight after 2 days of water deprivation, the elimination rate constant of the drug was significantly decreased (P<0.01) and the total body clearance was significantly slower (P<0.001). No statistically significant changes were observed in the pharmacokinetic parameters describing the distribution of the drug at this dehydration level. 3. Water deprivation for 3 or 4 days resulted in a level of dehydration at which the goats lost an average of 10.3% or 12.7% of their body weight, respectively; significant changes were observed in the pharmacokinetic distribution and elimination parameters of oxytetracycline. The volume of distribution at steady state was significantly decreased (P<0.01). Significantly slower total body clearance (P<0.001) and subsequent prolongation of the elimination half-life were found at these dehydration levels. 4. The alterations caused by dehydration on the disposition kinetics of the drug should be considered for better definition of dosage regimens for sick, dehydrated animals

Pharmacokinetics of ampicillin trihydrate following intravenous administration to water deprived Nubian goats

The present study reports the effect of water deprivation in the Nubian goat on the pharmacokinetics of ampicillin trihydrate following intravenous administration at a dose rate of 10 mg kg-1. Water deprivation for two days, which resulted in about 7.5 per cent loss in bodyweight, produced no significant effects on the pharmacokinetic parameters of the drug. In dehydrated goats that had lost an average of 9.8 per cent of their initial bodyweights, within three days of water deprivation, ampicillin showed significantly slower clearance values (P < 0.001), without affecting significantly the pharmacokinetic parameters describing the distribution of the drug. After four days of water deprivation a dehydration level at which goats lost an average of 12.6 per cent bodyweight was reached, which resulted in significant alterations in the distribution and elimination pharmacokinetic parameters of ampicillin. The volume of the central compartment (Vc) and the volume of distribution at steady state (Vdss) were significantly decreased (P < 0.01) leading to significant elevation in plasma concentrations of the drug (P < 0.01) compared with the normally hydrated animals. In water deprived goats, significantly slower clearance of the drug (P < 0.001) and reduced elimination rate constant (P < 0.01) with the subsequent increases in the half-life time were also observed. Dosage intervals between the usual doses of ampicillin can be increased in dehydrated goats and concentrations which were high enough to kill susceptible microorganisms could still be achieved