An accurate procedure for the analysis of azithromycin in ferret feces using solid phase extraction and HPLC

Azithromycin has become one of the most widely prescribed macrolide antibiotics due to the pharmacokinetic profile and broad spectrum of activity. A method for determining the level of azithromycin in ferret feces involving drying, methylene chloride extraction, solid phase extraction (SPE) clean-up, and HPLC analysis was developed. The method was linear from 0.8 to 3.2 mg/mL with a mean recovery of 97% (0.6% RSD for 50 mg spiked simulated feces). The analysis was developed to quantitate approximately 50 mg of azithromycin in approximately 0.6g of dried feces. The HPLC method uses a pH 7.5 phosphate buffered mobile phase with a conventional C-18 column and UV detection at 205 nm. The HPLC system is robust and column life is at least 1 month (similar to 200 injections).