The Chemical Laboratory

CRYSTALLINE SULFATHIAZOLE  Chemical and pharmacologie data on the compound 2-(P>-aminobenzenesulfonamido)-thiazole, for which the nonproprietary name sulfathiazole has been adopted by the Council on Pharmacy and Chemistry, were published by Fosbinder and Walter² in August 1939. Intense interest in sulfanilamide and its derivatives on the part of the medical profession prompted commercial production of sulfathiazole in quantities sufficient for thorough clinical evaluation. In June 1940, specimens of commercial sulfathiazole were presented to the A. M. A. Chemical Laboratory for examination at the request of the Council on Pharmacy and Chemistry. Preliminary investigation of the submitted brands of sulfathiazole by Dr. E. W. Schoeffel, a former member of the Laboratory staff, led to the discovery of a peculiarity in the melting characteristics of this compound. This information was transmitted to Dr. Theodore G. Klumpp, Chief, Drug Division, U. S. Food and Drug Administration, who instigated an investigation mentioned later. The melting points were determined by two methods: (a) the method given in the U. S. P. XI and (b) a method which involves observation of small quantities of material on an electrically heated stage under a microscope. Each method is susceptible of standardization against National Bureau of Standards calibrated thermometers.The first of two specimens of sulfathiazole supplied by the Maltbie Chemical Company was found to melt at about 178 C.; the second was found to contain some crystals which melted at about 178 C, together with a bulk of material which melted at about 202 C. This information was in contrast to melting point data found for portions of specimens of sulfathiazole submitted by the Calco Chemical Division American Cyanamid Company,