200 THE ANTIBIOTICS 



neamine. By paper chromatography catenulin may be distinguished 

 from neomycin A and B and the streptomycins. 



Biological activity: Active against various mycobacteria; shows cross re- 

 sistance with neomycin. 



Toxicity: LD B o (mice), intravenous, 125 mg/kg. Neurotoxicity in cats. 



Utilization. Probably same as neomycin. 



Reference. Davisson, J. W., Antibiotics & Chemotherapy, 2, 1952, 460- 

 462; Szybalski, W., Bact. Proc, 1952, 40. 



Chloramphenicol 



Produced by: Streplomyces venezuelae, S. omiyaensis. 



Synonym: Chloromycetin. 



Method of extraction: Extraction of acidified culture filtrates with ethyl 



acetate, concentration in vacuo, extraction with ether, chromatography 



over aluminum oxide. Can also be synthesized chemically. 

 Chemical and physical properties: Neutral stable substance containing 



nonionic chlorine, m.p. 149.7-150.7°C; [a]l 5 - 25.5° in ethyl acetate. 



Very soluble in methanol, ethanol, butanol, propylene glycol, and 



acetone. Slightly soluble in water. CiiHi8N 2 6 Cl2. 

 Biological activity: Active against gram-positive bacteria, gram-negative 



bacteria, and rickettsiae. 

 Toxicity: LD 50 (mice), intravenous, 150 mg/kg. 



Utilization: Treatment of infections caused by rickettsiae and bacteria. 

 Reference: Ehrlich, J., Bartz, Q. R., Smith, R. M., Joslyn, D. A., and 



Burkholder, P. R., Science, 106, 1947, 417. 



Chlortetracycline 



Produced by: Streptomyces aureofaciens. 



Synonyms: Duomycin, aureomycin. 



Method of extraction: No data. 



Chemical and physical properties: Weak base containing nonionic chlorine. 

 Very closely related to oxytetracycline. m.p. 168-169°C; [a]f — 275° 

 in methanol. Very soluble in cellosolve, dioxane, and alkaline water. 

 Slightly soluble in methanol, ethanol, butanol, acetone, ethyl acetate, 

 benzene, and water. Insoluble in ether and petroleum ether. 

 C22H23N2O8CI. 



Biological activity: Active against gram-positive bacteria, gram-negative 

 bacteria, and rickettsiae. Growth-promoting action in pigs and chicks. 



Toxicity: LD 6 o (mice), intravenous, 102-134 mg/kg; subcutaneous, <600 

 mg/kg; oral, <3000 mg/kg. 



Utilization: Treatment of bacterial and rickettsial infections. Feed supple- 

 ments. 



