Keywords: nanoparticles, nanogel, surface modification, colon, oral drug delivery, gastrointestinal tract, drug targeting, nanoparticles-in-microspheres, nanotechnology, oral drug administration, oral administration, tumour cells, inflamed tissue, colonic drug delivery
Nanoparticulate systems for oral drug delivery to the colon
A review of oral drug delivery to the colon is a difficult but desirable method of administration. In order to target the colon the dosage form must overcome the barriers presented by the gastrointestinal tract including the steep pH gradient, binding to the mucus layer, premature clearance, and premature cellular uptake. Nanoparticles have been fabricated via a number of methods and designed specifically to overcome these challenges. Drug entrapment with subsequent particle coating, surface modification, drug adhesion to a nanoparticle surface, and nanogel systems have all been used to target the delivery of drugs directly to the colon following oral administration. Further targeting of nanoparticles to specific cells within the colon such as tumour cells or inflamed tissue has also been made possible to better treat certain disease states. These colonic nanoparticle drug delivery systems are presented herein.