Simultaneous Achiral/Chiral HPLC Separation of Ketoprofen, Ibuprofen, Flurbiprofen, and Naproxen

Abstract

An HPLC method that separates four Non-Steroidal Anti-Inflammatory Drugs (Ketoprofen, Naproxen, Ibuprofen, and Flurbiprofen) and three of the four pairs of enantiomers in one run is reported. The NSAID samples were prepared with 1 mg/mL of Ketoprofen, Naproxen, Ibuprofen and Flurbiprofen, and 0.5 mg/mL thiourea as a t0 marker in a sample solvent consisting of 1: 1 acetonitrile and 0.2% formic acid. The separation of the enantiomers of the NSAIDs was investigated using a chiral column in two different lengths (5-cm, 10-cm) packed with Amylose tris(3,5-dimethylphenylcarbamate) coated on silica gel and using a tandem column that consists of a biphenyl column connected by a zero dead volume connector to a 5-cm chiral column packed with amylose tris(3,5-dimethylphenylcarbamate) coated on silica gel. Both isocratic and step-gradient methods were investigated, and the results of the different methods were compared to determine the benefits and drawbacks of each approach, with an emphasis on the resolution and analysis time.