title: Effects of cryoprotectants on the viability and activity of freeze dried recombinant yeasts as novel oral drug delivery systems assessed by an artificial digestive system.
abstract: The aim of this study was to investigate, in a gastric-small intestinal system TIM-1, the effect of cryoprotectants on the survival of freeze-dried Saccharomyces cerevisiae expressing the heterologous P450 73A1 and their ability to convert trans-cinnamic acid into p-coumaric acid. Yeasts were lyophilized in suspensions of trehalose, maltose, lactose, or a milk proteins/trehalose mix. Freeze-dried or native yeasts and trans-cinnamic acid were introduced simultaneously into TIM-1 at the beginning of digestion. Yeast survival rate was evaluated by cell counting in the ileal effluents. P450 73A1 activity was followed by HPLC assay of p-coumaric acid. Freeze-dried yeasts showed high tolerance to digestive conditions. Nevertheless, their survival rate was lower than that of non-dried cells (around 80% whatever the protective agent vs. 96%). The ability of recombinant freeze-dried S. cerevisiae to perform a bioconversion reaction in the digestive tract was shown with all the protectants. The highest trans-cinnamic acid conversion rate (24 vs. 41% for native yeasts) was obtained with the milk proteins/trehalose mix. These results show that freeze-drying might be considered for the pharmaceutical formulation of new drug delivery systems based on orally administered recombinant yeasts and that TIM-1 could be a helpful tool for the pre-screening of oral dosage forms.
authors: Equipe de Recherche Technologique Conception, Ingénierie et Développement de l'Aliment et du Médicament (ERT CIDAM), Centre de Recherche en Nutrition Humaine (CRNH) d'Auvergne, Faculté de Pharmacie, Université d'Auvergne, Clermont-Ferrand, France.
authors: Stéphanie
authors: S
authors: Blanquet
authors: Ghislain
authors: G
authors: Garrait
authors: Erick
authors: E
authors: Beyssac
authors: Céline
authors: C
authors: Perrier
authors: Sylvain
authors: S
authors: Denis
authors: Géraldine
authors: G
authors: Hébrard
authors: Monique
authors: M
authors: Alric
mesh_terms: D003451:Cryoprotective Agents / Q000494:pharmacology*; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis*; D016503:Drug Delivery Systems / Q000379:methods*; D005612:Freeze Drying; D041981:Gastrointestinal Tract / Q000378:metabolism*; D005818:Genetic Engineering; D006368:Helianthus / Q000201:enzymology / Q000235:genetics; D006801:Humans; D006899:Mixed Function Oxygenases / Q000096:biosynthesis*; D008954:Models, Biological; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics; D050564:Trans-Cinnamate 4-Monooxygenase
chemical_list: D003451:Cryoprotective Agents; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D050564:Trans-Cinnamate 4-Monooxygenase