Absorption, distribution, metabolism, and excretion of bacteria-derived hyaluronic acid in rats and rabbits.

The feasibility of using bacteria-derived hyaluronate solution as a viscous aid for anterior chamber surgery was examined by studying the pharmacokinetic behavior and metabolic fate of 14C-labelled material, following administration to rats and rabbits. Intravenously-administered HA disappeared rapidly from the blood of rabbits and rats with a mean t1/2 of 5.3 and 3.7 min, respectively. The labelled material has concomittantly accumulated in the liver, where it was digested to oligomeric sugar subunits; these were further utilized metabolically either for energy generation or for incorporation into new high molecular weight species. Metabolic cage studies has indicated that most of the 14C-HA label administered intravenously to rats was excreted as CO2 via the respiration within 24h, while a smaller portion was excreted in the urine. The disposition of viscous 14C-HA administered into the anterior eye chamber of rabbits was slow and followed first-order kinetics with a t1/2 of 10.5h. No degradation occurred in the aqueous humour. Low blood levels of 14C-labeled material were found during 72h after intra-ocular administration. The results indicate that the absorption, distribution, metabolism and excretion of bacteria-derived HA is similar to those of the currently used ophthalmic surgery HA aids extracted from rooster combs.