Effects of Insulin-Mimetic Vanadyl-Poly(γ-Glutamic Acid) Complex on Diabetic Rat Model

ABSTRACT Poly-g-glutamic acid (g-PGA) prepared by fermentation of microbe was used as drug carrier for vanadium sulfate to obtain vanadyl-poly-g-glutamic acid (VO-γ-PGA) complex. The FI-IR spectrum of the complex demonstrated that the expected VO-γ-PGA complex is formed by the coordination of VO 2+ through the side chain carboxylic groups of the γ-PGA. Studies of the complex in treating type I diabetes were carried out on alloxan induced diabetes rats. The results of treating the rats in 2 weeks and then stopping administration for 10 days showed that VO-γ-PGA can effectively lower blood glucose levels of diabetic rats during administration. But after ceasing treatment there were no differences between groups in blood glucose level and water intake. The results of oral glucose tolerance and some serum parameters also demonstrated that VO-γ-PGA was more effective than vanadium sulfate in treating diabetic rats. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:3041-3047, 2010 Keywords: vanadium; vanadyl sulfate; poly-γ-glutamic acid; vanadyl-poly-γ-glutamic acid; diabetes