Rapid spot test analysis for the detection of urotropine in pharmaceuticalpreparations

The widespread falsification and/or adulteration of commercially available pharmaceutical preparations call for reliable methods of drug identificatio n, preferably through selective and rapid sorting color tests that could be undertaken with minimum equipment remote from laboratory facilities. The p resent work deals with a convenient adaptation and refinement of a spot tes t devised by Feigl (1966) for urotropine, based on the hydrolytic cleavage of that substance in the presence of sulfuric acid, splitting out formaldeh yde which is identified by its color reaction with chromotropic acid. A sim ple emergency kit was developed for the quick, efficient, inexpensive and e asy performance of urotropine tests by semiskilled personnel even in the dr ugstore laboratory (or office) as well as in a mobile screening operation. It is shown that when the reagents are added according to the recommended s equence a self-heating system is generated, increasing substantially the re actions' rates and the test sensitivity as well. The identification limit f ound was 25 mug of urotropine, for both solid and liquid samples. The possi ble interference of 84 substances/materials was investigated. Interference was noted only for methylene blue, acriflavine, Ponceau Red, Bordeaux Red ( these dyes are often included in urotropine dosage forms), pyramidone, dipy rone, quinine and tetracycline. A simple procedure for removing most of the interferences is described. Data for 8 commercial dosage forms and results obtained from their analysis are presented.