title: Controlled release of oxytetracycline in sheep.
abstract: A novel biodegradable injectable formulation of oxytetracycline (OTC) was administered subcutaneously to sheep at a dose of 40 mg/kg. Blood samples were collected from the jugular vein at predetermined time intervals. The concentration of OTC in plasma was analyzed by an HPLC method. The concentrations of OTC in plasma were maintained at or above 0.5 microg/ml (minimum inhibitory concentration) for approximately 6 days. The pharmacokinetic parameters of OTC in sheep were also determined by monitoring the plasma concentration of OTC after a single intravenous injection of a commercially available OTC formulation at 10 mg/kg body weight. The in vivo release profiles of OTC from the biodegradable injectable formulations in sheep were determined from the plasma concentration time profiles by the deconvolution method using PCDCON software. The in vitro release of OTC from the biodegradable injectable formulation was tested in phosphate buffer (pH 7.4), containing 0.686% w/v of sodium sulfite as antioxidant. The correlation between the in vitro and in vivo release of OTC from the injectable formulation was also evaluated. The results of the in vivo evaluation of the formulation in sheep indicated that a controlled release biodegradable injectable dosage form of OTC for food animals is feasible.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee, Memphis, TN 38163, USA.
authors.forename: Yichun
authors.initials: Y
authors.lastname: Sun
authors.forename: Yingxu
authors.initials: Y
authors.lastname: Peng
authors.forename: Napasinee
authors.initials: N
authors.lastname: Aksornkoae
authors.forename: James R
authors.initials: JR
authors.lastname: Johnson
authors.forename: J Gregg
authors.initials: JG
authors.lastname: Boring
authors.forename: Daniel
authors.initials: D
authors.lastname: Scruggs
authors.forename: Robert C
authors.initials: RC
authors.lastname: Cooper
authors.forename: S Casey
authors.initials: SC
authors.lastname: Laizure
authors.forename: Atul J
authors.initials: AJ
authors.lastname: Shukla
mesh_terms: D000818:Animals; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000493:pharmacokinetics; D005260:Female; D010118:Oxytetracycline / Q000008:administration & dosage* / Q000097:blood* / Q000493:pharmacokinetics; D012756:Sheep; D040521:Subcutaneous Tissue / Q000187:drug effects / Q000378:metabolism
chemical_list: D003692:Delayed-Action Preparations; D010118:Oxytetracycline