Quantitative analysis of beta-adrenergic blocking agents by NMR spectroscopy.

The quantitative analysis by (1)H NMR of labetalol, oxprenolol and four other beta-adrenergic blocking agents is described. The method depends on the integration of selected resonances of the analyte and an internal reference which do not overlap. Procedures for the extraction of the analyte from tablets are given and corrections due to the NMR features of excipients outlined in some cases. The NMR method is reasonably precise and rapid, and the assay results compare favourably with those obtained by a UV procedure.