Drug delivery is among the most significant obstacles facing modern medicine: the more we manufacture drugs to treat specific unhealthy areas of the human body, the more we struggle with keeping those drugs out of the healthy ones. Researchers have been working to develop a technological fix by making controllable devices that are small enough to move about within biological systems. Last week researchers from the National Institute of Health (NIH) and Wayne State University in Detroit published a paper reporting the successful use of nanodevices in crossing the blood-brain barrier to treat cerebral palsy in rabbits. This breakthrough research in drug delivery is the first step towards the development more extensive methods based on technological advances in nanotechnology.
Last month, the David Gracias Laboratory at Johns Hopkins University published a review paper discussing the application of micro and nano-scale technologies to biological systems. Gracias and his group focus generally on miniaturization of engineered systems to better interface with biological ones. The paper, published in the journal Advanced Drug Delivery Reviews, gives the outlook for miniaturized machines in this increasingly important field. In particular, their focus is on developing micro and nanoscopic drug “capsules” that can travel through the body and open up under specific pre-defined conditions. These delivery systems are created to self-assemble and disassemble using intermolecular forces that are modified by surrounding environment. This way, medical researchers may be able to design devices that will only open and deliver drugs locally under certain predetermined conditions, solving an age old problem in medicine.
The human body is a complex and integrated system and administering drugs globally can be problematic. Two major problems arise, the first is that certain drugs or treatments can be harmful to the unaffected parts of the body, and the second is ensuring that enough of the drug will find it to the affected area. This problem is especially difficult when it comes to treating neurological disease; the blood-brain barrier makes it difficult to administer drugs to treat neurological diseases without invasive intervention into the brain.
Cerebral palsy, the focus of the NIH study on rabbits, is a neurological condition affecting early childhood development. It is generally caused by an exaggerated immune response in the brain that leads to inflammation and brain damage that significantly affects motor function. There is no effective cure or particularly effective preventive measures currently in use due to the difficulty of detection and treatment young children or fetuses. The NIH group was successfully able to dramatically reduce the motor impairment effects of cerebral palsy in rabbits by using nanoscale delivery devices to transport anti-inflammatory compounds to the brain, reducing the damage done by exaggerated immune response. Importantly, these nano-drug capsules were easily able to cross the blood-brain barrier, representing an important step for drug delivery technology, and possibly opening the door for widespread development of targeted drugs delivery using engineered devices. The technology is not quite ready for clinical tests in humans, but could possibly be incorporated into preventative treatment of very high risk infants.
With impressive results in animal laboratory studies, we are likely to see the development and testing of nanoscopic drug delivery technologies in human biological systems. Currently, there is no specific regulation on the use of nanoparticles and nanostructures in humans, but earlier this month the FDA released two draft guidance documents for food and cosmetic applications, but not medicinal ones. These two documents are the latest in a series of government steps to examine the regulation of nanotechnology that started with a 2007 study by the FDA. The news was also reported and discussed in the journal Science.