The technology has the potential to release a therapeutic in response to a specific external stimulus, for example light, pH or temperature. Targeted delivery has become increasingly important for the pharmaceutical industry as it attempts to deliver high doses of therapeutics without inflicting side effects on the body. MIPs potential applications are discussed in the research paper which stated: "The environmental variables involved, such as low pH and elevated temperatures, are characteristic features of the human body. "Thus, the properties of these materials open up new possible targeting systems for the recognition of large molecules (proteins, oligonucleotides, etc) useful in gene therapy and in selective interactions with cell surfaces." This pursuit of improved drug delivery techniques has caused a rapid expansion in the market, growing from $26bn in 2000 to $67bn in 2006. MIPs are one of the technologies that could drive this growth over the coming years. MIPs are formed in the presence of a target molecule which is then removed. After its extraction specific substrate recognition sites from the target molecule are moulded into the polymer. When an agent interacts with the substrate recognition site the therapeutic molecule is released. A range of variety of agents can be used to trigger this release but light is one which has some unique advantages as the level of control over the drug release is superior. This is because release can be triggered by applying a specific amount of light instantaneously and with high accuracy, giving a physician a great deal of control over the active component's delivery. It has been suggested that a wavelength of light which is not absorbed or reflected by tissues could be used to activate the drug delivery mechanism deep within the body. Although this level of control is in many respects very desirable other MIPs which rely upon changes in the body's conditions to trigger delivery may prove more practical for home consumption. Work has been conducted into utilising the body's natural physiological cycles to trigger therapeutic release. One such study used hydrocortisone as a template in the creation of the MIP. The MIP was then loaded with testosterone which was released when the drug delivery system came into contact with hydrocortisone. Although further work is needed it is conceivable that the researchers' conclusion that MIPs will "profoundly impact the field of drug delivery" may ring true in the future.
