Diffusion characteristics of chitosan-entrapped microsomal UDP-glucuronyl transferase gel beads.

Rabbit hepatic microsomal UDP-glucuronyl transferase (EC 2.4.1.17) was immobilized by entrapment in chitosan which is an ionotropic gelation agent and the resulting preparation was used as a biocatalyst for the glucuronidation of 1-naphthol in order to study the drug metabolism in vitro and obtaining artificial liver support (detoxification). In this study, depending on the porous structure of the chitosan/UDPGT gel beads, mainly the diffusion characteristics of 1-naphthol from chitosan gel beads in well stirred solutions were investigated, and the values of the effective diffusion coefficients (Dc) indicate that UDP-glucuronyl transferase in chitosan beads has no additional diffusion barrier. Using the data, the capacity of the chitosan-gel as an immobilization matrix for microsomal UDP-glucuronyl transferase is discussed from the point of view of diffusion characteristics.