Polymer-phloridzin conjugates as an anti-diabetic drug that inhibits glucose absorption through the Na+/glucose cotransporter (SGLT1) in the small intestine

J Control Release. 2008 Jan 4;125(1):42-9. doi: 10.1016/j.jconrel.2007.10.001. Epub 2007 Oct 13.


Poly(gamma-glutamic acid)s (gamma-PGA) modified with phloridzin, which is an inhibitor of the Na(+)/glucose cotransporter (SGLT1), via a omega-amino triethylene glycol linker were synthesized. The potential of gamma-PGA-phloridzin conjugates (PGA-PRZs) obtained as a novel oral anti-diabetic drug was examined by in vitro and in vivo experiments. A PGA-PRZ with a 15% phloridzin content inhibited glucose transport from mucosal to serosal sides of the everted rat's small intestine, and its inhibitory effect was as strong as that of intact phloridzin. When the PGA-PRZ was given orally to rats before glucose administration, the glucose-induced hyperglycemic effect was significantly suppressed. On the other hand, reduction of an increase in the blood glucose concentration was scarcely observed when the PGA-PRZ was substituted with a double amount of intact phloridzin. This difference in the biological activity between PGA-PRZ and intact phloridzin might have resulted from the improved stability of a glucoside bond of phloridzin through the conjugation with gamma-PGA. These results suggest that the gamma-PGA-phloridzin conjugates have potential as oral anti-diabetic drugs.

MeSH terms

  • Administration, Oral
  • Animals
  • Blood Glucose / analysis
  • Drug Carriers / chemical synthesis
  • Drug Carriers / chemistry*
  • Drug Stability
  • Glucose / metabolism*
  • Hydrolysis
  • Hypoglycemic Agents / administration & dosage
  • Hypoglycemic Agents / chemistry
  • Hypoglycemic Agents / pharmacokinetics
  • Hypoglycemic Agents / pharmacology*
  • Intestinal Absorption
  • Intestine, Small / drug effects*
  • Intestine, Small / enzymology
  • Intestine, Small / metabolism
  • Male
  • Molecular Structure
  • Phlorhizin / administration & dosage
  • Phlorhizin / chemistry
  • Phlorhizin / pharmacokinetics
  • Phlorhizin / pharmacology*
  • Polyglutamic Acid / analogs & derivatives*
  • Polyglutamic Acid / chemical synthesis
  • Polyglutamic Acid / chemistry
  • Rats
  • Rats, Wistar
  • Sodium-Glucose Transporter 1 / metabolism*
  • beta-Glucosidase / metabolism


  • Blood Glucose
  • Drug Carriers
  • Hypoglycemic Agents
  • Slc5a1 protein, rat
  • Sodium-Glucose Transporter 1
  • poly(gamma-glutamic acid)
  • Polyglutamic Acid
  • Phlorhizin
  • beta-Glucosidase
  • Glucose