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

Abstract

A bioavailability and pharmacokinetics study of doxycycline was carried out on 30 healthy ostriches after a single intravenous (IV), intramuscular (IM) and oral dose of 15 mg/kg body weight. The plasma doxycycline concentration was determined by HPLC/UV at 0 (pretreatment), 0.08, 0.25, 0.5 1, 2, 4, 6, 8, 12, 24 and 48 h after administration. The plasma concentration-time curves were examined using non-compartmental methods based on the statistical moment theory for only the higher dose. After IV administration, the elimination half-life (t1/2β), mean residence time (MRT), volume of distribution at the steady-state (Vss), volume of distribution (Vdarea) and total body clearance (ClB) were 7.67 ± 0.62 h, 6.68 ± 0.86 h, 0.86 ± 0.16 l/kg, 1.67 ± 0.52 l/kg and 2.51 ± 0.63 ml/min/kg, respectively. After IM and oral dosing, the mean peak plasma concentrations (Cmax) were 1.34 ± 0.33 and 0.30 ± 0.04 µg/ml, respectively, which were achieved at a post-administration time (tmax) of 0.75 ± 0.18, 3.03 ± 0.48 h, respectively. The t1/2β, Vdarea and ClB after IM administration were 25.02 ± 3.98 h, 23.99 ± 3.4 l/kg and 12.14 ± 1.71 ml/min/kg, respectively and 19.25 ± 2.53 h, 61.49 ± 7 l/kg and 40.19 ± 3.79 ml/min/kg after oral administration, respectively. The absolute bioavailability (F) of doxycycline was 5.03 and 17.52% after oral and IM administration, respectively. These results show that the dose data from other animals particularly mammals cannot be extrapolated to ostriches. Therefore, based on these results along with those reported in the literature, further studies on the pharmacokinetic/pharmacodynamic, in vitro minimum inhibitory concentration values and clinical applications of doxycycline in ostriches are required.

Pharmacokinetics of doxycycline after a single intravenous, oral or intramuscular dose in Muscovy ducks (Cairina moschata)

“…Therefore, the present study could be further refined to determine the influence of age on the pharmacokinetics of doxycycline in ducks after different routes of administration. The Vss of doxycycline reported here was 0.590.89 ml/kg, consistent with that in 12-week-old turkeys (0.530.17 l/kg, Santos et al, 1997), higher than in chickens (0.110.01 l/kg, Anadon et al, 1994), but lower than in ostriches (0.860.16 l/kg, Abu-Basha et al, 2006), and in 3 d, 3-, and 6-week-old turkeys (1. 770.22, 2.140.24, and 0.650.35 l/kg, respectively, Santos et al, 1997).…”

“…In the present study, the volume of distribution (Vz) of doxycycline in ducks after IV administration was 1.760.33 l/kg, in accordance with that in ostriches (1.67±0.52 l/kg, Abu-Basha et al, 2006), but higher than that reported in chickens (0.280.02 l/kg, Anadon et al, 1994). Santos et al (1997) reported that the Vz of doxycycline in 3 d, 3-, 6-and 12-week-old turkeys were 2.83±0.19, 4.10±0.40, 1.26±0.51 and 0.85±0.02 l/kg, respectively, which indicated that the V z of doxycycline in turkeys decreased with increasing age.…”

“…Following IV administration, the terminal half-life (t 1/2λz ) was 21.211.47 h, which was longer than reported in chickens (4.750.21 h, Anadon et al, 1994), ostriches (7.67±0.62 h, Abu-Basha et al, 2006), and turkeys (7. 90-10.79 h, Santos et al, 1997).…”

“…Such differences are relatively common and frequently related to inter-species variation, assay methods used, time between blood samplings, health status and age of the animals. The Cl of doxycycline in ducks was 57.519.50 ml/h/ kg, which was close to that in 12-week-old turkeys (60 ml/h/kg, Santos et al, 1997), higher than in broiler chickens (40 ml/h/kg, Anadon et al, 1994), but lower than in ostriches (150.6 ml/h/kg, Abu-Basha et al, 2006). Santos et al (1997) reported A c c e p t e d M a n u s c r i p t that age influenced Cl in turkeys, and 3-week-old turkeys had the highest Cl of 270 ml/h/ kg, while Mycoplasma gallisepticum infection increased doxycycline's Cl in chickens (Ismail and El-Kattan, 2004).…”

Comparative Study of Three Different Brands of Doxycycline Capsules Available in Karachi

“…Bacteria [1]. It is a bacterioststic agent having a broad spectrum activity against Gram-positive and Gram-negative anaerobic and aerobic bacteria, Mycoplasmas, Chlamydiae, Rickettsiae, and some Protozoa [2]. Doxycycline was firstly invented and clinically developed by Pfizer Inc., New York in the early 1960s and marketed under the trade name Vibramycin [3] [4].…”