Liquid chromatographic determination of acetaminophen in multicomponent analgesic tablets

A simple, rapid LC method is presented for the separation and determination of acetaminophen in analgesic preparations containing up to 6 additional active components. The method uses a C18 reverse phase column, methanol-0.75% acetic acid (1 + 3) mobile phase, and photometric detection in the ultraviolet region. Acetaminophen was effectively separated from chlorpheniramine maleate, phenylephrine hydrochloride, caffeine, salicylamide, aspirin, and phenacetin, as well as from salicylic acid, a degradation product of aspirin. Typical chromatograms of the separation of acetaminophen from the above compounds in synthetic mixture and in commercial multicomponent analgesic preparations are presented, along with reproducibility and recovery data.