Disposition kinetics of doxycycline in chickens naturally infected with Mycoplasma gallisepticum

Abstract

1. The pharmacokinetic properties of doxycycline were determined in healthy chickens and chickens naturally infected with Mycoplasma gallisepticum after a single intravenous (i.v.) and oral administration of the drug at 20 mg/kg body weight. Tissue residues of the tested drug after an oral dose of 20 mg/kg given twice daily for 5 consecutive days were also estimated in diseased chickens. 2. The plasma concentrations of doxycycline following single i.v. and oral administration were higher in healthy chickens than in diseased ones. Following i.v. injection, the elimination half-life (t1/2beta), distribution half-life and mean residence time (MRT) were longer in healthy chickens than in diseased birds. The values of total body clearance (ClB) and volume of distribution (Vdss) were larger in healthy chickens than in diseased birds. 3. After single oral administration, the absorption half-life (tl/2ab) and the elimination half-life were longer in normal birds than in diseased ones. The maximum plasma concentration of the drug was higher in normal chickens than in diseased ones. 4. Following repeated oral administration, the concentration of doxycycline in all tissues except muscle was higher than the corresponding concentrations in plasma. Concentrations of doxycycline in different tissues were in the following order: kidney > liver > lung > muscle. The drug was detected in liver and kidney in substantial concentrations on d 5 post administration of the last dose whereas, on d 7, its concentration in all tissues was below the lower limit of the sensitivity of the assay method used. Because of the low sensitivity of the microbiological assay method used in this study, a safe withdrawal time for doxycycline in diseased birds could not be estimated for the meanwhile.

Pharmacokinetics and bioavailability of doxycycline in ostriches (Struthio camelus) at two different dose rates

“…These results are in agreement with those reported for goats [2] and pigs [25] but lower than those reported for healthy East African dwarf goats [23]. The mean plasma concentration detected in ostrich plasma after the IM administration of doxycycline (15 mg/kg body weight) was higher than the MICs for Mycoplasma gallisepticum (0.2 µg/ml) [15], Mycoplasma Pneumoniae (< 0.5 µg/ml) [33], Bacteroides fragilis (0.016-0.032) [21], Staphylococcus aureus (0.25 µg/ml) [8], Streptococcus pneumoniae (< 0.4 µg/ml) [4], Streptococcus zooepidemicus (< 1.0 µg/ml) [8], Chlamydia psittaci (0.05-0.2 µg/ml) [9] and porcine bacterial respiratory tract pathogens ( Pasteurella multocida , Bordetella bronchiseotica , Actinobacillus pleyropneumoniae and Mycoplasma hyopneumoniae ) (0.016-2 µg/ml) [7,24]. However, the doxycycline plasma concentration was lower than the MICs for E. coli (1-4 µg/ml), Pseudomonas aeruginosa (> 64 µg/ml) [22] and Enterococcus fecalis (8-32 µg/ml) [14].…”

“…After the oral administration of doxycycline at a dose of 15 mg/kg body weight, the t 1/2β (19.25 h) was different from those reported in pigs [5,25], chickens [15], horses [12], and calves [20]. The Vd area was higher and the Cl B was lower than those reported in pigs [5].…”

Residues of sulfadiazine and doxycycline in broiler liver and muscle tissue due to cross-contamination of feed

“…This difference may be due to differences in oral administration and the duration of the administration, a dose of 15 mg kg À1 was provided orally twice daily over 5 successive days. Doxycycline had higher residue concentrations in the liver compared to muscle, as reflected by the feed/tissue transfer ratios, which has also been described previously (Atef et al 2002;Ismail and El-Kattan 2004). Doxycycline is known to be well absorbed from the gastro-intestinal tract (Yoshimura et al 1991), to have a high volume of distribution with the highest detected levels in liver and kidney (EMEA 1996) and to have high tissue binding (Santos et al 1997).…”

Pharmacokinetics, tissue residues and efficacy of D-Tylo50/25® (tylosin-doxycycline combination) in broiler chickens

“…[18][19][20] Doxycycline was eliminated with half-life (t 1/2β ) equal to 7.62 h. The long t 1/2β is a clear characteristic of doxycycline in different species, which range from 4.2 to 16.6 h. 18,19,21 High volume of distribution (5.51 L/kg) and a low total body clearance (0.57 L/kg/h) indicates that doxycycline is rapidly absorbed, widely distributed and slowly eliminated in body of chickens as reported by. [18][19][20] Following oral administration, of doxycycline, elimination half-life (t 1/2el ) was 8.97 h. This value varies with age of chickens between 10 and 12 h. 22,23 However, these values are notably different from the t 1/2el values of 3.64 to 4.75 h reported in chickens. 4,18,24 The oral bioavailability of doxycycline in this study was 94.30%, indicated a good absorption from GIT.…”