High-performance liquid chromatographic assay of codeine in acetaminophen with codeine dosage forms.

An accurate, rapid, and specific high-performance liquid chromatographic (HPLC) assay was developed for codeine in acetaminophen with codeine combination products. The internal standard (chlorpheniramine maleate), codeine, acetaminophen, and several other test compounds or impurities were well separated. A complete analysis took < 10 min. The relative standard deviations of the retention time, precision, and accuracy were 0.5, 0.4, and 0.5%, respectively. An excellent linear correlation was obtained between the HPLC and GLC methods.