Full text loading...
Chapter 47 : Primycin
Primycin is a product obtained from fermentation of Thermomonospora galeriensis, and is a complex of macrocyclic antibiotics comprising 20 compounds. This molecular complex is stable, and the molecules are linked to one another by hydrogen bonds. Primycin is insoluble in water, moderately soluble in methanol and 1,2-propanediol, and freely soluble in warm N-methylpyrroli-done, and it forms a stable gel that can contain up to 30% primycin (Ebrimycin). This gel forms the basis of the various pharmaceutical preparations. The molecular mass is on the order of 1,000 Da for each of the components, and the pK is 11. The median lethal dose in the mouse is greater than 3,000 mg/kg of body weight orally and 56 mg/kg intraperitoneally. No skin lesions have been observed after chronic cutaneous applications (90 days) in rabbits. Primycin possesses good in vitro antibacterial activity against Staphylococcus aureus and coagulase-negative staphylococci, but its activity against Streptococcus pyogenes and enterococci is moderate. After oral administration of 10 mg of primycin per kg to rats, no antibacterial activity was measured in the plasma (microbiological method using Bacillus subtilis) between 30 and 360 min after administration. The results were the same when primycin was administered at a dosage of 5 mg/kg for 7 days. No antibiotic activity was detected in the serum after application of 250 mg/kg.