BIOL 166 |
| A novel reaction system was developed for the production of metabolites of compounds poorly soluble in water using mammalian liver microsomes as reaction catalyst. The system is based on the use of hydrophobic polymeric resin serving as a reservoir for the hydrophobic parent compound and its metabolites. The utility of the extractive biotransformation approach was demonstrated for the production of a low yielding hydroxylated metabolite of antibiotic rifalazil, 32-hydroxy-rifalazil, using mouse liver microsomes. In order to address the problem of the very low solubility of rifalazil in the predominantly aqueous microsomal catalytic system, a variety of strategies we've developed for the enhanced delivery of hydrophobic substrates were tested, including the addition of mild detergents, polyvinylpyrrolidone, glycerol, bovine serum albumin, and hydrophobic polymeric resins. The latter strategy (extractive biotransformation) was identified as the most effective for the production of 32-hydroxy-rifalazil, resulting in up to 13-fold enhancement of the volumetric productivity compared to the standard aqueous system operating at the solubility limit of rifalazil. The production process was rapidly optimized for a wide range of reaction parameters; the most important for the volumetric productivity included the type and amount of the polymeric resin, type of the cofactor recycling system, concentration of the catalyst and rifalazil, reaction temperature, and agitation rate. The optimized reaction system was used for the synthesis of 32-hydroxy-rifalazil on a multi-milligram scale. The structural identity of the synthesized product was confirmed by LC/MS characterization and comparison of HPLC results with authentic reaction products produced by human liver microsomes. The research was sponsored by ActivBiotics, Inc. |
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Chemistry and Metabolism
4:30 PM-6:30 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Division of Biological Chemistry |