204 THE ANTIBIOTICS 



tion to dryness; suspension of solid in water, extraction with ether to 

 remove impurities; adjustment of pH of water portion to 4.5 with 

 formation of an active precipitate. 



Chemical and physical properties: High molecular weight acid containing 

 3.7 per cent N. Soluble in alcohols and methyl cellosolve. Insoluble 

 in water, ether, chloroform, benzene, ethyl acetate, and other fat 

 solvents. Stable at 100°C for 30 minutes. 



Biological activity. Active against bacteria and fungi. More active against 

 yeast-like fungi (0.5-2.5 mcg/ml) than against filamentous fungi 

 (12-25 mcg/ml). More active against gram-positive bacteria than 

 against gram-negative bacteria. 



Toxicity: No clear data available. Mice killed by injections of 1 gm/kg, 

 not by 0.5 gm/kg. 



Utilization: No information. 



Reference: Gottlieb, D., Bhattacharyya, P. K., Carter, H. E., and Ander- 

 son, H. W., Phytopathology, 41, 1951, 393-400. 



Erythromycin 



Produced by: Streptomyces erythreus. 



Synonyms: Ilotycin, Erythrocin. 



Method of extraction: From the alkaline broth with benzene, ethyl acetate, 

 carbon tetrachloride, etc. 



Chemical and physical properties: Basic compound soluble in water (2 

 mg/ml), very soluble in alcohols and acetone, chloroform, and ethyl 

 acetate. Moderately soluble in ether, ethylene dichloride, and amyl 

 acetate. Molecular weight 725. [a]l 5 — 78° in alcohol. Maximum light 

 absorption at 280 m/i. The acid degradation of erythromycin yields 

 two bases, dimethyl amine and a second base having the following 

 empirical formula CgHnNOs • HC1 . 



Biological activity: Active against gram-positive bacteria, including coryne- 

 bacteria; not active against gram-negative bacteria, except Neisseria, 

 Hemophilus, and Brucella; active against mycobacteria, rickettsiae, 

 and large viruses; active against certain protozoa. Development of 

 resistance slow. 



Toxicity: LDw (mice), oral, about 4000 mg/kg; subcutaneous, 1800 mg/kg. 



Utilization: Can be used in certain cases to replace penicillin, chlortetra- 

 cycline, oxy tetracycline, or chloramphenicol. 



Reference: McGuire, J. M., Antibiotics & Chemotherapy, 2, 1952, 281; 

 Heilman, F. R., Herrell, W. E., Wellman, W. H., and Geraci, J. E., 

 Proc. Staff Meetings, Mayo Clinic, 27, 1952, 285; Haight, T. H., and 

 Finland, M., New Engl. J. Med., 247, 1952, 227. 



