Validation of Liquid Chromatographic Method of Assay for Acetaminophen, Butalbital and Caffeine in Solid Dosage Forms

The validation of a liquid chromatographic procedure for the determination of acetaminophen, butalbital and caffeine in solid dosage forms is described. The dosage content of tablets or capsules is diluted and chromatographed on a Radialpak Cyanopropylsilane Cartridge with a mobile phase of water-acetonitrile-1M dibutylamine phosphate (90+9+1, V/V) with detection at 215 nm. The calibration curve is linear with correlation coefficients of 0.999 for each component. Recoveries of spiked excipient blend averaged 99.5% for acetaminophen, 102.5% for butalbital and 101.0% for caffeine. The method met USP requirements for system suitability with proper resolution between two adjacent peaks. The relative standard deviation (RSD) of peak response of each component (obtained by chromatographing six replicates of standard solution) is less than 2.0% and the tailing factor of each component is not greater than 1.5. The method can be used for composite, content uniformity and dissolution assay of acetaminophen, butalbital and caffeine in tablet and capsule formulations.