Simultaneous assay of hydrocodone bitartrate and acetaminophen in a tablet formulation

A reversed-phase pressurized liquid chromatographic procedure is presented for the simultaneous quantitation of hydrocodone bitartrate and acetaminophen in a tablet formulation. The separation method was based on an octadecylsilane column with a buffered (pH 4.5) methanol-water mobile phase. Measurement was with a UV spectrophotometer set at 283 nm, compared to external standards. Assays for the active ingredients in tablet samples averaged 99.7% of the label claim for hydrocodone bitartrate and 100.3% for acetaminophen. The respective relative standard deviations of the retention time and precision were 2.2 and 1.75% for hydrocodone and 3.3 and 0.95% for acetaminophen. The range of interest studied was 0.035 to 0.065 mg/ml for hydrocodone bitartrate and 3.50 to 6.50 mg/ml for acetaminophen. The assay method was also compared to colorimetric and USP procedures for the active ingredients. The method was suitable for control, content uniformity, and stability-indicating use.