The disposition of theophylline in camels after intravenous administration.
The pharmacokinetics of theophylline were determined after an intravenous (i.v.) dose of 2.36 mg/kg in six camels and 4.72 mg/kg body weight in three camels. The data obtained (median and range) for the low and high dose, respectively, were as follows: the distribution half-lives (t1/2 alpha) were 1.37 (0.64-3.25) and 2.66 (0.83-3.5) h, the elimination half-lives (t1/2 beta) were 11.8 (8.25-14.9) and 10.4 (10.0-13.5) h, the steady state volumes of distribution (Vss) were 0.88 (0.62-1.54) and 0.76 (0.63-0.76) L/kg, volumes of the central compartment (Vc) were 0.41 (0.35-0.63) and 0.51 (0.36-0.52) L/kg, total body clearances (Clt) were 62.3 (39.4-97.0) and 50.2 (47.7-67.4) mL/h.kg body weight and renal clearance (Vr) for the low dose was 0.6 (0.42-0.96) mL/h.kg body weight. There was no significant difference in the pharmacokinetic parameters between the two doses. Theophylline protein binding at a concentration of 5 micrograms/mL was 32.2 +/- 3.3%. Caffeine was identified as a theophylline metabolite but its concentration in serum and urine was small. Based on the pharmacokinetic values obtained in this study, a dosage of 7.5 mg/kg body weight administered by i.v. injection at 12 h intervals can be recommended. This dosing regimen should achieve an average steady state serum concentration of 10 micrograms/mL with peak serum concentration not exceeding 15 micrograms/mL.
Wasfi
I A
IA
Camelracing Laboratory, Abu Dhabi, United Arab Emirates. iawasfi@emirates.net.ae
Elghazali
M
M
Boni
N S
NS
Hadi
A A
AA
Alhadrami
G A
GA
Almuhrami
A M
AM
Alkatheeri
N A
NA
Barezaiq
I M
IM
Agha
B A
BA
Wajid
S A
SA
D000818:Animals; D019540:Area Under Curve; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D002162:Camelus / Q000378:metabolism*; D005260:Female; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D013806:Theophylline / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
D001993:Bronchodilator Agents; D013806:Theophylline