SULPHONAMIDES 



143 



qntrycide 



CI, 



Single doses of 1 mg. per kg. were effective in curing infections with Trypanosoma 

 congolense, etc., and the drug is also prophylactic. If cattle can be reared in tsetse-fly 

 belt areas of Central Africa the effect on the world's meat supply may be remarkable. 

 (Curd and Davey, 1949.) 



SULPHONAMIDES, ACTION OF DRUGS 



In view of the trypanocidal action of certain organic arsenical compounds 

 containing the peptide linkage CO.NH, it was decided to synthesise and test the 

 sulphur analogues containing the sulphonamide group, — SOg-NH (Hewitt and King, 

 1926 ; Hewitt, King and Murch, 1926). Two of the compounds investigated were 

 3^-amino-benzoyl-4-amino-2 hydroxyphenyl arsonic acid and the sulphur analogue 

 3^-amino benzene sulphoryl-4-amino-2-hydroxy-phenylarsonic acid :— 



NHa O H 



( VcO-NH-/ VsOgHs 



NH2 OH 



/ \-S02-Nh/ VsOgH; 



Therapeutic results against Trypanosoma equiperdum were disappointing, the 

 sulphur analogue being four times as toxic as the peptide, and the investigation of 

 sulphur analogues was abandoned. In Germany, however, work on these was evidently 

 continuing since we had an intimation from workers there that patent rights were 

 involved and in 1932, Prontosil was patented. Domagk in 1935, showed that this 

 red dye was effective against streptococcal infections in animals, and Colebrook and 

 Kenny established its value in puerperal septicaemia. Patients frequently developed 

 a rosy pink colour when treated with Prontosil Rubrum. As a result of the work of 

 Trefouel, Buttle, Colebrook, Fuller, Hare and their colleagues it was estabUshed that 

 Prontosil was broken down in the body and the active compound was p-amino- 

 benzenesulphonamide. 



