A new drug delivery system could allow doctors to target medication precisely and ensure that only diseased tissue receives the drug.
The system has been successful in animals, and if it works in humans will be a major advance in drug delivery. The technique could, for example, reduce side effects caused by toxic drugs used in chemotherapy.
In the new technique, researchers take a sample of the patient’s blood, infuse it with drugs, then put the blood through a process that makes it release the medication when exposed to ultrasound.
“Essentially the blood cells are exposed to an electric field which … opens up their pores to allow drugs to go in,” said Dr. Les Russell, CEO of Gendel, the company formed to exploit the process.
The blood holding the drug is reintroduced to the patient and ultrasound is applied to the area where the drug is required, for example, in the kidneys. When the drug-laden blood cells arrive at the kidneys, the ultrasound causes them to burst open and deliver their payload.
The upshot is that medication is applied only where it is needed. Red blood cells have been used to carry drugs before, but until now there was no way to target where they were released.
“The concept of resealed erythrocytes (red blood cells) is not new. You can load some drugs in it and later it can be released,” said Dr. Sudip Das, associate professor of pharmaceutics at Idaho State University.
“But the major question is: How is the drug released? This company is using ultrasound, which is a novel technique, no doubt, but I would need to see more information to judge it properly,” Das said. To that end, Gendel is preparing a paper for publication in a peer-reviewed journal.
Meanwhile, the inventor of the process sees it as far more than novel. “It is a tremendous improvement over existing techniques for loading drugs,” said professor Tony McHale, of the University or Ulster’s School of <Biomedical Sciences at Coleraine, Northern Ireland.
“The red blood cells pass through the beam and accumulate enough energy to break open,” McHale said. “This technology means that we can determine when and where the cells deliver their load of medicines, enabling us to target diseased or infected tissue with great accuracy.”
“Red blood cells are essentially like a big bag for carrying oxygen around,” Russell said. “We can put quite a lot of drug in there.”
The drug delivery system replaces oxygen with medication. At 20 milliliters, the quantities of blood cells used for drug delivery are small. By comparison, the average human has 5 liters of blood so the patient will not miss the oxygen lost. More importantly, animal tests so far show that the blood cells are treated as ordinary blood cells in the body and are not rejected.
So far, however, tests have only taken place in animals and Russell said it is impossible to tell exactly when the system will be approved for use in hospitals. The company recently received about $3 million venture capital funding to pay for human trials. They hope to be in trials in the next year.
“Many (cancer) drugs used are cytotoxic (destructive to living cells) and that means that they have side effects like sickness, nausea (and) hair loss,” he said.
Harsh side effects occur to get the dose they need at the site, doctors need to subject patients to high overall dosages.
Also, many chemotherapy drugs have a short lifetime, and doctors need to repeat treatments often.
Gendel’s system keeps drugs fresh within the blood cell and delivers the drug locally, so fewer and far smaller doses are required, Russell said. That minimizes the quantity of medication released, as well as minimizing any side effects.
Ultimately, the company hopes its system will be installed in hospitals so a patient’s blood can be collected, infused with the necessary drugs and reintroduced into the bloodstream at the bedside or in the operating room.
