Biological availability of chlortetracyclinium chloride in sheep after administration of Vubivet C prm.a.u.v. in milk or water

The standard chlortetracyclinium chloride biological availability and other pharmacokinetic parameters were observed in adult sheep of the Slovak meri no breed after administration of Vubivet C prm. in milk and in water. Both groups were given chlortetracyclinium chloride in Vubivet C prm. a.u.v. pre paration (Biotika, Slovenska Lzupca, Slovak Republic) in a single dose of 2 0 mg/kg live weight accounting for 6.66 g of preparation per 10 kg live wei ght. The preparation was administered per os in 2 % suspension by probe. Ch lortetracyclinium chloride concentrations in blood serum were determined ch romatographically after 1, 3, 6, 12 and 24 hour, according to Sokol and Mat isova (1994) with liquid chromotograph. After administration of Vubivet C p rm. in milk, significantly lower serum concentrations of chlortetetracyclin ium chloride (p.05) were detected at 1, 3, 6 and 12 hours as compared with the comparison standard in water. The ratio between the total area under th e curve of chlortetracyclinium chloride concentration in the blood serum af ter Vubivet C prm. administration in milk and water indicated tl,at biologi cal availability of Vubivet C prm. administered in milk is 33.79 % lower th an in water. When the preparation was applied in water the biological half- time of chlortetracyclinium chloride was 8.64 hr and 8.82 hr when applied i n milk. If antimicrobial therapy of sucklings fed milk is necessary with th is preparation, or other peroral preparations on the basis of classical tet racyclines, we recommend them to be administered in water or other liquid. After application or before administration (at an interval of 2-3 hours) mi lk or milky feed mixture may be given. The above mentioned recommendation i s supported by the finding that serum concentrations of chlortetracyclinium chloride after administration in milk are higher than the MIC but the obta ined values would most likely not be effective in medium susceptible strain s.