SALVARSAN AND NEOSALVARSAN IN TREATMENT OF SYPHILIS 795 



In experimental syphilis of rabbits the minimal dose necessary to 

 produce a complete cure was found to be between 0.01 and 0.015 gram 

 per kilogram. The tolerated dose by intravenous injection is 0.1 gram; 

 the curative dose of salvarsan in syphilis of rabbits is, therefore, only 

 from one-seventh to one-tenth of the tolerated dose. 



Properties of Neosalvarsan. This is an orange-yellow powder 

 possessing a peculiar odor. It is very unstable in the air and is readily 

 soluble in water, yielding a yellow solution that is neutral to litmus. Its 

 structure is somewhat more complex than that of salvarsan, being a 

 condensation-product of the latter and hydraldit (formaldehyd sulph- 

 oxylate of sodium), the reaction taking place according to the follow- 

 ing equation: 



As As As 



NH 2 | ] = [ I NH 2 + HO.CH.O.SO Na = NH 2 



01 



AS AS 



o-o 



OH OH 



As 



JNH. 



CH 2 O.SO Na+H 2 



While neosalvarsan is less toxic than salvarsan, and although it is 

 much more easily administered and largely free from irritative effects, 

 recent clinical reports would tend to show that its spirocheticidal prop- 

 erties are somewhat less than those of salvarsan. 



Methods of Preparing Salvarsan for Administration. Soon after 

 the introduction of the drug several methods of preparation and adminis- 

 tration were suggested. Many of the disadvantages attached to sal- 

 varsan treatment, and many of the bad results and complications re- 

 ported, are to be attributed to defective methods of preparation and 

 administration of the drug. 



Because of the marked stability of salvarsan and neosalvarsan, the 

 following points must be borne in mind: 



1. The ampule containing the drug must be intact. 



2. The powder must be of a yellow and not of a gray or brownish color. 

 Each ampule must be carefully examined before the contents are 



administered. 



3. The drug should be prepared for injection just prior to administra- 

 tion. 



