Pharmacokinetic data on doxycycline and its distribution in different biological fluids in female goats

✍ Scribed by V. K. Jha; C. Jayachandran; M. K. Singh; S. D. Singh

• Book ID: 104742634
• Publisher: Springer Netherlands
• Year: 1989
• Tongue: English
• Weight: 372 KB
• Volume: 13
• Category: Article
• ISSN: 0165-7380
• DOI: 10.1007/bf00366847

✦ Synopsis

A pharmacokinetic study of doxycycline after intravenous administration at 5 mg/kg body weight in goats revealed that a concentration of 50.5 &ml was maintained for 5 min-2 h, 4-12 h, 2-12 h and 5 min->4I? h in plasma, interstitial fluid, milk and urine respectively. The low tl/za of 0.73 f 0.11 h and high ti/@ of 16.63 f 158 h show that the drug is rapidly distributed but slowly eliminated from the body. The tissue:plasma concentration of 4.86 z 1.06 during the elimination phase [Bz/(K21-fl)] indicates a high expected tissue concentration, which is supported by similarly increased drug concentration in interstitial fluid and milk The high V~UU of 9.78 2 0.86 L/kg observed denotes that, apart from its wide distribution, the drug may be stored in fat depots as it is known to be highly lipophilic. As the drug maintained a therapeutic concentration for a shorter time in plasma, and the calculated dose rate for maintaining a minimal plasma concentration of 05-1.5 &ml is relatively high, it may not be of much use in treating septicaemia in this species. Since the observed tissue:plasma concentration was higher and a therapeutic concentration was maintained in interstitial fluid and milk for longer, the drug can be used for other systemic infections at a lower dose rate than that required for treating septicaemia. As the drug maintained a very high concentration in urine, it may be of particular value in treating urinary tract infections caused by sensitive microorganisms.