Determination Of Bacitracin Research Articles

Competitive enzyme-linked immunosorbent assay for the determination of zinc bacitracin in animal feedingstuffs.

Traditionally, bioassay has been the chosen technique for the determination of bacitracin compounds in animal feedingstuffs. However, detection and determination of this antibiotic have given problems when it is present at low levels. A competitive enzyme-linked immunosorbent assay (ELISA) by which it is possible to detect both bacitracin and zinc bacitracin at levels as low as 1 mg kg-1 in animal feeds is described. The ELISA technique has been used in this laboratory to monitor samples from a drug stability storage trial for the presence of zinc bacitracin. In addition, individual polypeptide components of zinc bacitracin have been separated by high-performance liquid chromatography. Fractions were collected and tested by the ELISA technique to assess the response between individual components and the primary antibody. The response was compared with known microbiological activity.

蛍光検出器付き高速液体クロマトグラフィーによる豚および鶏肉中のバシトラシンの定量

蛍光検出器付き高速液体クロマトグラフィーによる豚および鶏肉中のバシトラシンの定量

Pyridine Extraction Method for Determination of Bacitracin in Feeds: Collaborative Evaluation

Seventeen laboratories evaluated the pyridine extraction method and neomycin-sensitized agar for the determination of zinc and MD bacitracin in swine and broiler rations at 10 and 100 g/ton. The method was also applied to the analysis of 2 premixes labeled 50 g/lb (MD bacitracin) and 40 g/lb (zinc bacitracin). Bacitracin activity was determined on each of 2 days with 2 dilutions on each day. No significant difference was found between dilutions within a day or between days for each sample. The type of bacitracin or type of feed did not significantly affect results. The difference in results between MD and zinc bacitracin in premixes approached significance. The large coefficients of variation for premixes (ca 13%) and complete feeds (ca 15--30%) indicate operational problems. The main difficulty was evaporation of pyridine. Some laboratories were not able to evaporate it completely, whereas others lost bacitracin activity, probably due to high temperature of drying. The pyridine extraction method as in 42.200 and 42.204 should be discontinued.

Determination of bacitracin by differential pulse polarography

Differential pulse polarograms of pharmaceutical-grade bacitracin exhibit a well-defined double wave at the dropping mercury electrode over the entire pH range 1–8. The current is diffusion-controlled and proportional to the concentration as well as to the biological activity of the sample. The concentration of bacitracin and of zinc—bacitracin can be determined by pulse polarography with a standard deviation less than 2%. The biologically inactive oxidation product (bacitracin F) is reduced at less negative potentials and can easily be determined in the presence of the biologically active components of bacitracin.

Determination of bacitracin in animal feeds that contain copper.

A modification of the method involving the use of acidified methanol for the analysis of animal feeds that contain bacitracin and copper sulphate as additives has been developed. Because of the interference of copper in the bacitracin assay, the copper is precipitated by the addition of 3 to 4 mol of sulphide ions per mole of copper. The method has been used for feed samples that contain 5 to 20 p.p.m. of bacitracin and 100 to 300 p.p.m. of copper

An improved method for the determination of bacitracin in animal feeds.

The determination of small amounts of bacitracin in animal feeds has been studied. It was expected that by using acidified methanol as the only organic solvent in the extraction procedure and phosphate buffer, undesired proteins would not be dissolved and the use of the toxic solvent pyridine might be avoided. Bacitracin could then be determined in the final extract by using microbiological methods, in which methanol interferes less than pyridine. The method reported here has been used for feed mixtures with various zinc bacitracin contents in the range from 5 to 350 p.p.m.