Intestinal Transport of Human Insulin in Rat

An everted intestinal sac technique has been used to extensively estimate the transport of regular human insulin in rats. As the preliminary experiments using an injectable vial of the insulin showed a considerable transport of insulin, this composition was used deliberately instead of combination of crystalline form of this substance and a permeation enhancer. Two series of experiments were performed with insulin concentrations of 12 and 3.4 u/ml and concentrations of transported insulin were determined with HPLC in serosal fluid of the sac. The results indicated that, in all experiments about 85% of insulin was transported across the medial jejunum segment of rat during an hour regardless of the insulin concentration used. Therefore, a number of factors such as the excipient incorporated with the insulin, pH, the nature of solvent and its ionic strength may play important role in enhancing insulin transport.