Erythromycin in the udder - Results of pharmacokinetic study on bioavailability

Concentration of Erythromycin in the milk was investigated following a sing le intracisternal administration with ERYTROTIL (Sanofi-Ceva GmbH, Dusseldo rf). A 6-ml-injector with 300 mg Erythromycin was used. Samples of 10 mi we re manually milked within three to 24 hours post administration. A specific ally developed extraction technique was employed for sample preparation. Er ythromycin concentrations were determined by means of a specifically develo ped and validated HPLC-method (High Pressure Liquid Chromatography). Therap eutically effective concentrations of Erythromycin in the milk were determi ned over a period of 24 hours. The dosage used in this studie and a repeate d administration every 24 hours guarantee a long lasting therapeutic concen tration of Erythromycin in the milk.