Elimination Of Tilmicosin In Lactating Ewes
Abstract: Summary:
Tilmicosin was injected subcutaneously to lactating ewes once at a dose of 10 mg kg' b.wt. to determine its plasma, milk, urine arid ruminal juice concentrations. Tilmicosin could be detected in all those fluids 30 minutes after injection. Milk and urine concen¬trations were higher than those of plasma and ruminal juice. The drug was detectable in milk, urine and plasma for 9, 4 and 3 days after injection, respectively. No amount of tilmicosin could be detected in ruminal juice 12 hours following administration. The mean peak concentration of tilmicosin in plasma and milk (Cm„») were 1.29 and 9.5 ug ml' and were obtained at (Tm„) 5.235 and 15.093 hours, respectively. The drug was slo¬wly eliminated from plasma and milk as indicated by its long half-life (t1/2J of 15.4 and 26.2 hours, respectively.
The mean binding of tilmicosin to plasma and milk proteins in vitro was 16.8 % and 26.8 %, respectively. The drug was not bound to ruminal juice at any extent. The rate of tilmicosin renal clearance revealed that it was correspondingly increased with higher blood concentrations. While creatinine clearance showed no significant change after tilmicosin administration. The ratio (fractional clearance) between tilmicosin renal clea¬rance to creatinine clearance was less than one indicating that the glomerular filtration is the main pathway of elimination through kidneys.
The rate of ruminal gas fermentation in ewes was inhibited after subcutaneous injection of tilmicosin at a dose of 10 mg kg-' b.wt. The tested samples taken at different time in¬tervals from the rumen of ewes showed a subsequent reduction in the rate of fermen¬tation as compared to control samples. The reduction was correspondingly increased with the increase of tilmicosin concentration in ruminal juice and returned to normal thereafter.
Keywords: tilmicosin, pharmacokinetics, milk, excretion, ruminal juice, ewes.

Keywords: tilmicosin, pharmacokinetics, milk, excretion, ruminal juice, ewes
Publication year 1999
Pages 291-294
Availability location معهد بحوث التناسليات الحيوانبة الهرم
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Organization Name
Author(s) from ARC
External authors (outside ARC)
    عاطف محمد كلية الطب-قسم الادواية البيطرية جامعة القاهرة
    خالد ابو السعود كلية الطب البيطرى-قسم الادواية البيطرية جامعة القاهرة
    ناهد الخولى معهد صحة الحيوان
Agris Categories Veterinary science and hygiene - General aspects
Proposed Agrovoc tilmicosin, pharmacokinetics,;
Publication Type Researsh & Applied Activities
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