A thin walled microtube is formed by providing a continuous elongated member having an outer surface. The member is at least partially formed of a water soluble material. A coating material is provided. The coating material may be a silicone compound that is curable such that the coating material cures...http://www.google.es/patents/USRE41870?utm_source=gb-gplus-sharePatente USRE41870 - Method for forming hollow fibers
