A bright future for drug delivery

Irish researchers have developed a method that could be used to deliver controlled amounts of drugs to diseased tissues while minimizing side effects by shining light on the target.

A new drug dosing system controlled by light has been developed by scientists at Queen's University Belfast. The research show how pro-drug molecules containing a carboxylic acid group can be turned into ester-containg drugs by shining a light source onto them. The system could allow the ability to deliver drugs where, when, and in the exact doses, required. This would maximize their effect and reduce side effects and damage to healthy parts of the body.

 Dr Colin P. McCoy and colleagues from the School of Pharmacy at Queen's describe their new molecular-scale dosing devices as "a new paradigm for precise control of drug dosing using light." The devices consist of medications combined with certain chemical compounds that respond to light in ways that release precisely controlled amounts of the drug. Drug release begins when light falls on the compounds, and lasts only as long as the light continues to shine.The research, published as an early view article in the Journal of the American Chemical Society, showed successful laboratory tests of the system in the controlled release of three common medications used to treat pain and inflammation - aspirin, ibuprofen and ketoprofen.

 Explaining some of the potential uses for the new method, Dr McCoy said: "One potential use we cited in the study would be in the treatment of urinary catheter infections, where the drug is held latently in the catheter, and is released when needed using light from a fibre optic. The system could likewise be used for other conditions using an implant under the skin for precisely controlled drug dosing." The researchers are now looking at expanding the method to classes of drug molecules other than the ester-containing systems studied in the paper.

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