High-performance liquid chromatographic assay of antiinflammatory drugs incorporated in gel ointments. Separation and stability testing

High-performance liquid chromatographic determinations of gabexate mesilate (FOY), prostaglandin E1 (PGE1), PGE1-alpha-cyclodextrin (PGE1-CD), prednisolone (PD) and butyl flufenamate (BF) incorporated in gel ointment were investigated. The gel ointment is composed of a carboxy vinyl polymer (1.3%, w/w) and a large amount of an aqueous organic solvent. A methanol extraction system offered simultaneous advantages of the removal of the polymer and the recovery of active ingredients from the gel phase. The recoveries of the drugs were 100%. The stabilities of PGE1, PGE1-CD, FOY, PD and BF incorporated in gel ointment, stored at 5, 25 and 40 degrees C for up to 90 days, were investigated.