Glaphenine-containing gallstones.

Glaphenine is an analgesic drug derived from anthranilic acid. We report the analytical procedures for stone analysis in three cases of common bile duct stones containing glaphenic acid, which developed in arthrosic patients treated for 13.7 +/- 5 years with glaphenine. Stone analysis was performed by infrared spectroscopy, high performance thin layer chromatography, scanning electron microscopy and energy dispersive X-ray analysis. Mechanisms of lithogenesis are discussed. These observations emphasize the possibility of radiolucent gallstones mainly composed of drug compounds.