Zwcens and Frankcna: Simultaneous delermination of dimcthadione and trimethadione

A simple infrared-spectrometric method for the Simultaneous determination of dimethadione and trimethadione in plasma is described. The method is based on the absorption band of the carbonyl group for trimethadione at the wavenumber of 1740 cm" and for dimethadione at the wavenumber of 1770 cirT. The accuracy and precison of the method are excellent; at a dimethadione and trimethadione concentration of 0.5 mmol · 1 the coefficient of Variation for the determination of both compounds is <1%, which is better than that for the ultraviolet spectrometric or gas-liquid Chromatographie methods. The method can be used for the determination of the ratio trimethadione/dimethadione in the clinical setting äs a sensitive check of the patient's adherence to therapy. It can also be used for the determination of dimethadione äs an indicator for the mean body intracellular pH.