Beyond Needles And Pills

The numbers are staggering. Each year as many as 15% of all U.S. hospital admissions, some 100,000 deaths and $136 billion in medical costs result from harmful reactions to drugs. But relief is on the way. All too aware of the toll on the nation's health and pocketbook, medical researchers are devising a host of safer and more effective drug-delivery systems, many of them also designed to overcome the pain and inconvenience of traditional remedies. They range from such low-tech items as anal suppositories to innerspace-age microcraft reminiscent of the tiny ship that carried Raquel Welch through a patient's blood vessels in the movie Fantastic Voyage.

In their pursuit of better systems, researchers are finding ingenious ways to bypass such natural body defenses as the blood-brain barrier and the macrophages of the immune system, which can block or gobble up newly administered drugs. Another problem, says M.I.T. professor of biomedical engineering Robert Langer, is adverse effects that result even when "people take prescription drugs exactly as prescribed."

The trouble, says Langer, a leading innovator of drug-delivery systems, is that drugs do not stay at constant levels in the body. They typically start low, rise to a peak and then decline. When that happens, Langer says, "those peaks can sometimes be toxic and the valleys totally ineffective." He cites as examples insulin and sleeping pills: "Too much insulin can put you into a coma. Not getting enough insulin can be fatal. Too much sleeping pill can kill you. Too little, and you lie awake all night."

At the Battelle laboratories in Columbus, Ohio, researchers are working on those problems. They are devising painless alternatives to the hypodermic needle, fear of which causes many diabetics, for example, to delay necessary injections of insulin. One such device is the Mosquito, a small disk equipped with a tiny needle that penetrates only seven micrometers into the skin--not deep enough to impinge on nerve endings and cause pain. Attached to a patient's side, the disk allows mobility while it delivers the prescribed dose of drug evenly over a 24-hour period.

Another delivery system, the inhaler, is getting a second look. While inhalers have been used for years to treat asthma and, more recently, cystic fibrosis, only 10% of the medication actually reaches the deepest regions of the lungs. Battelle and other companies are designing inhalers that use compressed air and drug powders to push much more of the medication deep enough into the lungs to be effectively absorbed. Among the drugs that researchers hope will be administered with the new inhalers are antibiotics, insulin and interferon. Other new systems enable doctors to apply drugs through the eyes or through the mucous linings of the nose, mouth and vagina.