Читать книгу Uric Acid in Chronic Kidney Disease - Группа авторов - Страница 12

Uric acid is a heterocyclic compound (2,6,8-trihydroxypurine [C₅H₄N₄O₃]) and its diprotic acid characteristics include 2 dissociable protons with pKa₁ ≈5.4 and pKa₂ ≈10.3. At physiological human pH, the breakdown of uric acid occurs in 99%, forming acid urate ion in the extracellular fluid, mainly in its circulating form [1, 2].

In a constant neutral blood pH, the index between urate ion and uric acid remains stable and the average concentration of urate levels is close to the solubility limit (6.8 mg/dL). Both terms refer to the total uric acid value (dissociated and undissociated forms) [2]. Even though uric acid excretion happens through the kidneys, the urinary point of neutrality on the pH scale ranges from 4.6 to 8.0 but varies much more in lower urinary pH, increasing in greater proportion its undissociated form because of its poor solubility in aqueous solution [2].