Simultaneous determination of caffeine and non-steroidal anti-inflammatory drugs in pharmaceutical formulations and blood plasma by reversed-phase HPLC from linear gradient elution.

A reversed-phase HPLC procedure based on methanol-water gradient elution for determining caffeine and non-steroidal anti-inflammatory drugs with UV absorbance detection is proposed. Chromatographic operational conditions were selected by considering the peak resolution and the retention times of the first and last eluted compounds. The method was suitably validated and successfully applied to the determination of: caffeine, indoprofen, ketoprofen, naproxen, fenbufen and ibuprofen in blood plasma samples and several analgesic/antiphlogistic pharmaceutical formulations.