4.3 - CAPREOMYCIN

Abstract

Capreomycin is a peptide antibiotic produced by a new species of streptomycete, Streptomyces capreoulus. The product is prepared as the disulfate, and is an amorphous, white to slightly yellowish, odorless powder, soluble in water but insoluble in the common organic solvents. The powder has excellent shelf life, and aqueous solutions are stable at room temperature over the pH range of 3–9 for more than 24 h. The photometric assay has a range of 25–80 micrograms per tube and is used for the assay of purified antibiotic. The plate method has a range of 2–20 micrograms per milliliter, and is used either for estimating levels of antibiotic in serum and urine or for assay of purified antibiotic. There are quantitative differences in the microbiological activities of the capreomycins. Adoption of the photometric assay as a control method is based on the above correlative activities, the ease and speed of operation, accuracy, and the avoidance of slow growing or pathogenic mycobacteria. A cylinder plate method employing Bacillus subtilis is used primarily for the assay of capreomycin in biological materials. The choice of the organism is based mainly on its sensitivity. The plate method is used as an alternate assay for purified antibiotic. Results obtained by the plate method are in good statistical agreement with those by the photometric method for samples within the percentage composition range of components in commercial capreomycin sulfate.