MICROFABRICATED ORAL DRUG DELIVERY SYSTEMS

Microfabrication is a collection of techniques developed to fabricate micron sized features, best suited to develop the novel drug delivery microdevices. microfabrication techniques were originally developed in the microelectronics industry to produce functional devices on the micron scale such as sensors, switches, filters and gears. Approaches like modification of drug itself to improve its permeability/ solubility characters, encapsulation techniques using micro/nanoparticles, use of protease inhibitors to curb proteolytic degradation, and use of intelligent polymers and hydrogels do not offer a complete solution for adequate and safe delivery of drugs, vaccines, peptides, proteins and others. This technology has been applied to the successful fabrication of a variety of implantable and oral drug delivery devices based on silicon, glass, silicone elastomer or plastic materials. These techniques that are utilized at present have developed as a result of integrated circuit manufacturing technologies, such as photolithography, thin film growth/deposition, etching and bonding. Micromachining allows for control over surface features, aspect ratio, particle size, shape and facilitating the development of an engineered particle for drug delivery that can incorporate the advantages of microparticles while avoiding their design flaws. It helps in multi-cell and multi-site attachment, multiple reservoirs of desired size to contain multiple drugs/biomolecules of interest. These fabrication techniques have led to the development of microelectromechanical systems (MEMS), bioMEMS, micro-total analysis systems (μ-TAS), lab-on-a-chip and other microdevices. Microfabricated devices are designed for uni-directional release, to prevent enzyme degradation, precise dosing and better patient compliance. Drug delivery in the form of microparticles and micropatches have been used for targeted delivery as well as in treatment of diseases like diabetes and cancer.