NMR spectroscopic analysis of 2-mercapto-5-methyl-1,3,4-thiadiazole in cefazolin.
A rapid, sensitive, and accurate method for the quantitative analysis of 2-mercapto-5-methyl-1,3,4-thiadiazole in cefazolin is presented. The method utilizes NMR spectroscopy and is based on the difference in the chemical shift of the methyl protons on free thiadiazole and the thiadiazole moiety of cefazolin.
NMR analysis of pharmaceuticals. 8. Determination of trimethadione in various dosage forms.
An NMR procedure is described for the determination of trimethadione in its various pharmaceutical dosage forms. The method is both accurate and precise, with a standard deviation of ±0.3%. The NMR results of synthetic mixtures and commercial preparations were compared to those obtained by USP XVIII and NF XIII procedures. The NMR technique offers the advantages of speed, simplicity, and specificity.
Kinetics of Base-Catalyzed Hydrolysis of Trimethadione
An infrared method is reported for determination of intact trimethadione (3,5,5- trimethyl-2,4-oxazolidinedione) in presence of products of hydrolysis. Kinetics have been determined for hydroxide ion-catalyzed hydrolysis of trimethadione and a mechanism is proposed in which there exists a rapid equilibrium between a cyclic and an acyclic structure. The rate of hydrolysis of trimethadione at pH 10 and 30° is 105 to 106 times that for acyclic compounds of similar structure.