Separation of non-steroidal anti-inflammatory agents using supercritical fluid chromatography

Supercritical fluid chromatography (SFC) was investigated for the separation of non-steroidal anti-inflammatory agents (NSAIs). Three different stationary phases (SB-methyl-100, SB-biphenyl-30, and SB-cyanopropyl-50) were compared for the separation of the compounds. Baseline separation of a flufenamic acid, mefenamic acid, fenbufen and indomethacin mixture was achieved on the SB-biphenyl-30 column using a pressure gradient. A mixture containing flufenamic acid, mefenamic acid, acetylsalicylic acid, ketoprofen and fenbufen and another mixture containing ibuprofen, fenoprofen, naproxen, ketoprofen and tolmetin were well separated on the SB-cyanopropyl-50 column using pressure gradients. Typical analysis time for a mixture of NSAIs on the biphenyl or cyanopropyl column was approximately 20-25 min. Application of the method using the biphenyl column to the determination of NSAIs present in selected commercial dosage forms was demonstrated.