Simultaneous Determination of Multi-Component Dosage Forms Using Benchtop NMR Spectroscopy: Application to Phenytoin-phenobarbital combination Tablet

The use of nuclear magnetic resonance (NMR) spectroscopy, as a tool for the determination of pharmaceutical molecules in bulk drugs and their dosage forms is growing. New advancements of benchtop NMR spectrometers with cryogen-free magnets have made this technique more appealing and accessible. Herein, we developed a method using benchtop NMR spectrometer for the quantification of phenytoin (PhT) and phenobarbital (PhB) in bulk and combination dosage form and the results were compared to those obtained by HPLC, as a well-characterized procedure.Three signals atδ 0.79, 7.30, and 8.57 ppm were used for the quantification of PhB and PhT mixture through qNMR. Considering the 3 to 5 ratio of hydrogens of the methyl group to the hydrogens of the phenyl group of PhB and determining the share of PhB from the integral of the aromatic region signal, the share of PhT could be calculated and used to calculate its amount. This method is simple, low cost, relatively fast, and non-inferior to HPLC in terms of figures of merit.
Source: Iranian Journal of Pharmaceutical Research - Category: Drugs & Pharmacology Source Type: research