Effect of lysate vaccine on pharmacokinetics of enrofloxacin and tylosin in sheep

Abstract

In the present work, the effect of vaccination with lysate vaccine on the disposition kinetics of enrofloxacin and tylosin following intravenous and intramuscular injection in rams was studied. Bioavailability of both drugs were calculated in non vaccinated and vaccinated rams after a single intramuscular dose. 6.1. Enrofloxacin:

Following a single intravenous injection of 2.5 mg enrofloxacin/kg b.wt. in non vaccinated and vaccinated rams, the drug could be detected therapeutically for 24 hours with values equal to 0.33 ug/ml in non vaccinated rams and 0.5 ).lg/ml in vaccinated rams. The serum concentration time curve of enrofloxacin following intravenous injection showed that the drug obeyed a three compartments open model. The phannacokinetic parameters of enrofloxacin after a single intravenous injection in vaccinated rams revealed some significant J variations than in non vaccinated rams. These variations represented by higher distribution phase (a = 1.2 h-1 ) in vaccinated than in non

vaccinated rams (a = 1.2 h-1 ), while distribution half life (tos(uJ) decreased in vaccinated (0.46 h) than in non vaccinated rams (0.61 h). The volume of distribution of control compartment (V 1 ) was decreased significantly in vaccinated rams (0.127 Llkg) than in non vaccinated ones (0.206 Llkg) whereas the total body distribution calculated by extrapolation (V2 ), area (V3) and steady state ( Vctss) methods revealed significant decrease in vaccinated in comparison to those in non vaccinated rams. These variations in distribution of enrofloxacin between non vaccinated and vaccinated rams might be attributed to the