Vitamin B12 as a Carrier for the Oral Delivery of Insulin

The noninvasive delivery of insulin continues to be a major goal for the treatment of diabetes mellitus. Oral–enteric administration would make insulin delivery easier and more effective, as higher patient compliance and improved glycemic control are likely; yet the oral–enteric pathway has been unfeasible owing to insulin's susceptibility to proteolytic degradation and inefficient enteric uptake. Herein we show that a noninvasive oral delivery route for insulin is possible through the vitamin B12 uptake pathway. In diabetic rat models, insulin–B12 conjugates can significantly lower blood glucose levels when administered orally. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2452/2007/z700239_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.