Solution-mediated phase transformation of uric acid dihydrate

摘要: Various crystalline phases of uric acid are frequently identified components human kidney stones, including anhydrous (UA) and dihydrate (UAD). Herein we report a quantitative study the solution-mediated phase transformation metastable UAD to UA as function pH well in model urine solution. Using combination X-ray diffraction, thermal analysis, optical microscopy techniques, was found go completion within 48 hours at 37 °C buffered solutions with between 4.0–6.5 no evidence for intermediate phases. In > 6.8, different monosodium urate monohydrate becomes dominant. artificial solution, occurs on slightly faster timescale results smaller crystals. Seeding saturation experiments indicate that rate-limiting step overall is dissolution UAD. The kinetics these processes suggest interconversions various solid state forms relevant under physiologic conditions which lead stone formation.