To obtain information about the nature and extent of contamination with phenobarbital of certain specimens of tablets sulfathiazole-Winthrop, it was considered desirable to subject some of the tablets to chemical examination. Through the courtesy of the Winthrop Chemical Company, Inc., a number of samples were obtained from the specific lots of tablets, MP series, in which contamination was believed to have occurred. Samples were provided from every container in which these tablets were stored in the factory under "quarantine." In addition, two samples of the tablets from lot MP 029 were obtained from the Food and Drug Administration. A method of examining these tablets to detect and determine phenobarbital was devised, and the results of the examination are here reported. For comparison, specimens of sulfathiazole-Winthrop from lots known to be uncontaminated, and a specimen of tablets of luminal-Winthrop, a brand of phenobarbital, were examined concurrently.
Sulfathiazole-Winthrop is marketed in the