Antiadhesive Collagen Membrane with Heparin Slow Release

Abstract

A collagenous antiadhesive membrane with slow heparin release was tested in animal studies and found to exhibit antiadhesion activity. The antiadhesive membrane was prepared by crosslinking protamine to purified human amnion and then ionically binding heparin to the protamine. The amount of bound heparin was proportional to the protamine content in the collagen. The heparin was found to slowly release in vivo over a period of one month. The heparinized amnion was evaluated in canines. A portion of the serous membrane was removed from the intestine and the heparinized amnion was sutured onto the site. Observations up to 687 days after surgery revealed that the heparinized amnion showed satisfactory antiadhesion efficacy. Mesothelial cell proliferation lining on the site and normal wound healing was observed with no scar formation. The amnion was incorporated into the tissue and grad ually resorbed. In contrast, all unheparinized amnion controls showed consid erable adhesion and severe scar formation with distortion of the healed in testine. Two out of the four control dogs died of intestinal obstruction.