Liquid chromatographic determination of methocarbamol in injection and tablet dosage forms: collaborative study

A reverse phase liquid chromatographic method was developed for determining methocarbamol in injection and tablet dosage forms. The injections require dilution only; the tablets require a filtration step before introduction into the chromatograph. Response for methocarbamol was linear over the range 0-18 micrograms, using an ultraviolet detector at 274 nm. Recoveries by the author ranged from 96.1 to 101.9% for authentic injection formulations and 98.0 to 101.0% for authentic tablet formulations. A collaborative study of the method by 6 laboratories resulted in standard deviations of 1.70 and 2.22 for injection and tablet dosage forms, respectively. The method has been adopted official first action.