ANTIBIOTICS 



201 



application of many of these substances is still in doubt as 

 their use is often accompanied by damage to the kidney 

 tubules ; whether this is caused by toxic impurities or whether 

 it is a corollary of the excretion of peptide substances is not 

 yet known. 



4. AuREOMYCiN, Chloromycetin: These substances are 

 organic bases formed by species of Streptomyces and have a 

 wide range of antibacterial activities. Their discovery is of 

 great importance for several reasons: first, they are more 

 stable than other antibiotics that can be used chemothera- 

 peutically; second, they are the first substances to be effective 

 against rickettsial and virus diseases ; and third, the structure 

 of Chloromycetin is relatively simple and the active substance 

 has been synthesised. The synthesis is not difficult and 

 Chloromycetin will probably be the first antibiotic which can 

 be produced more cheaply by chemical synthesis than by 

 biological production. 



NO; 



HCOH 



HC NH- 



I 



^' 



CHCZ, 



Chloromycetin 



SuLPHONAMiDES : various derivatives of jo-amino-benzene- 

 sulphonamide are used with considerable success against 

 Gram-positive organisms, while some Gram-negative organ- 

 isms are susceptible to the action of the more active 

 derivatives such as sulphadiazine or sulphathiazole. Success- 

 ful derivatives are those in which the sulphonamido-N group 

 contains a substituent such as pyridine, pyrimidine, thiazole, 

 etc. ; the pyrimidine and thiazole derivatives have a relatively 

 high solubility in blood-plasma and can be used for disinfection 



