Emerging microtechnologies for the development of oral drug delivery devices

The development of oral drug delivery platforms for administering therapeutics in a safe and effective manner across the gastrointestinal epithelium is of much importance. A variety of delivery systems such as enterically coated tablets, capsules, particles, and liposomes have been developed to improve oral bioavailability of drugs. However, orally administered drugs suffer from poor localization and therapeutic efficacy due to various physiological conditions such as low pH, and high shear intestinal fluid flow. Novel platforms combining controlled release, improved adhesion, tissue penetration, and selective intestinal targeting may overcome these issues and potentially diminish the toxicity and high frequency of administration associated with conventional oral delivery. Microfabrication along with appropriate surface chemistry, provide a means to fabricate these platforms en masse with flexibility in tailoring the shape, size, reservoir volume, and surface characteristics of microdevices. Moreover, the same technology can be used to include integrated circuit technology and sensors for designing sophisticated autonomous drug delivery devices that promise to significantly improve point of care diagnostic and therapeutic medical applications. This review sheds light on some of the fabrication techniques and addresses a few of the microfabricated devices that can be effectively used for controlled oral drug delivery applications.