Oral insulin--a perspective.

Diabetes mellitus is generally controlled quite well with the administration of oral medications or by the use of insulin injections. The current practice is the use of one or more doses, intermediate or long acting insulin per day. Oral insulin is a promising yet experimental method providing tight glycemic control for patients with diabetes. A biologically adhesive delivery systems offer important advantage over conventional drug delivery systems. The engineered polymer microspheres made of erodable polymer display strong adhesive interactions with gastrointestinal mucus and cellular lining can traverse both the mucosal epithelium and the follicle associated epithelium covering the lymphoid tissue of Peyer's patches. Alginate, a natural polymer recovered from seaweed is being developed as a nanoparticle for the delivery of insulin without being destroyed in the stomach. Alginate is in fact finding application in biotechnology industry as thickening agent, a gelling agent and a colloid stabilizer. Alginate has in addition, several other properties that have enabled it to be used as a matrix for entrapment and for the delivery of a variety of proteins such as insulin and cells. These properties include: a relatively inert aqueous environment within the matrix; a mild room temperature encapsulation process free of organic solvents; a high gel porosity which allows for high diffusion rates of macromolecules; the ability to control this porosity with simple coating procedures and dissolution and biodegradation of the system under normal physiological conditions.