TITLE:
Pharmacokinetics and Efficacy of Tilmicosin in the Treatment of Pasteurella haemolytica Bronchopneumonia in Calves
AUTHORS:
Ahmed M. Soliman, Amer Ramadan Ali Ayad
KEYWORDS:
Tilmicosin, Disposition Kinetics, Calves, Healthy, Diseased, Bronchial Secretion
JOURNAL NAME:
Pharmacology & Pharmacy,
Vol.5 No.5,
May
22,
2014
ABSTRACT:
Tilmicosin was administered intravenously and
subcutaneously at a dose rate of 10 mg/kg bwt to determine its concentration in
blood and bronchial secretion as well as its kinetic behavior in healthy and Pasteurella
haemolytica type A1-infected calves. Sever acute bronchopneumonia was
induced in 10 calves by inoculating them intra-tracheally with P.
haemolytica type A1. The calves were treated with tilmicosin; 5 of these
received the drug intravenously and the other 5 were injected subcutaneously. After
a slow intravenous injection, the serum concentration-time curve indicated a
two compartment open model with a mean elimination half-lives (t1/2bs) of 22.09 and 22.14 hours before and after infection, respectively. The
mean residence time (MRT) corrected for a bolus injection was 2.25 and 2.20
hours and the mean MRTinf was 25.27 and 25.46 hours in healthy and P.
haemolytica-infected calves, respectively. After subcutaneous injection, the drug was
eliminated more slowly (before and after infection) from serum and bronchial
secretions, with t1/2bs of (24.60 and 25.85 hours) and (33.74 and 31.78
hours), respectively. The apparent volume of distribution (Vd(area))
of tilmicosin was more than 1 litre·kg-1. The peak serum and bronchial
secretions of tilmicosin concentration were (1.33 and 1.36 mg·ml-1) and (1.40 and 1.70 mg·ml-1) attained at (7.21 and 7.15 hours)
and 7.11 and 7.10 hours) after subcutaneous injection, respectively. Tilmicosin
was good secreted into bronchial secretions having AUCbronchial secretion/
AUCserum ratio of approximately 1:1.24 and 1:1.22 in healthy and P.
haemolytica-