Impurities in drugs V: Meprobamate.

ABSTRACT

One lot of meprobamate raw material and 28 lots of tablets were examined for impurities by TLC. All lots contained di-(2-methyl-2-propyl-3-carbamoyloxypropyl) carbonate (V) at levels that ranged between 0.1 and 1.0% of the total drug content. Nine lots also contained low levels of a second impurity (approximately 0.1%), and one of these lots contained a third impurity (approximately 0.1%), neither of which was identified. Estimates of the unidentified impurities were based on the assumption of a TLC response with furfural-hydrochloric acid spray equivalent to that of meprobamate. Compound V was identified by mass spectrometry and PMR and IR spectroscopy and by comparison of the TLC Rf value to that of a synthesized sample of V.