Before long, taking medication may not involve swallowing a pill or tolerating a needle anymore. That's because two companies and an academic institution are developing novel drug delivery methods, including contact lenses that convey controlled doses of medication, inhalation devices that use the lungs as the means into the bloodstream, and needle-free injection devices that shoot the liquid drug so fast that it pierces the skin.

No More Needles

Of the three new drug delivery methods, the needle-free injection device is the only one already on the market. Developed by Antares Pharma Inc., a PA-based medical device company, the gadget delivers drugs to patients who need insulin or human-growth hormone. Representing the company's only product for now, the reusable device is no bigger than a battery-powered toothbrush and features a spring-activated trigger, which discharges the drug in liquid form at such a tremendous velocity that it goes through the skin.

Dubbed the Medi-Jector Vision, the device is available over the counter to those who require insulin here in the United States. And in Europe, the device is being marketed by Ferring Pharmaceuticals of Denmark as a delivery mechanism for its human-growth hormone.

In fact, Antares is already busy developing the next generation Medi-Jector Vision device, which will be smaller, lighter and able to dispense drugs contained in cartridges, instead of vials, which the current system uses. Moreover, the company's president and CEO, Roger Harrison, says that the company is also at work on disposable and mini-needle versions of the system, which will be pre-filled with drugs, including perhaps vaccines, fertility agents and medication for migraine headaches, acute pain and cancer, and even antidotes to biological chemical toxins.

Although mini-needle technology does employ a needle, it is so tiny that users may not notice it, says Harrison. Indeed, the company's focus remains steadfastly on making needle-free delivery systems for drugs that can't be imbibed in pill form, marketing its systems to pharmaceutical companies, instead of selling directly to patients.

Apart from needle-free drug delivery devices and mini-needle technology, the company is also developing transdermal gels, which can be completely absorbed into the skin within minutes and can continue conveying a drug for up to 24 hours.

In short, the company is banking on a needle-free future. "There's a general agreement that technology has advanced to the point that someday in the future needles will be a scientific curiosity relegated to a museum somewhere," says Harrison. "There is a difference of opinion about when that day will be. My job is to make that day a lot nearer in the future."

Inhaling Your Medication

While needles may be inching toward obsolescence, inhalation devices are taking on a new function. Along with treating respiratory conditions, they may soon be able to deliver medication for diabetes and other ailments to the bloodstream via the lungs. California-based Aradigm Corp. is hard at work developing such devices and has already brought one of its inhalers—intended for insulin delivery—close to the end of clinical trials and much nearer to securing federal approval for commercial sale.

Aside from performing conventional inhaler functions, such as counteracting asthma or bronchitis, Aradigm's system, AERx, can spray drugs to the lungs and into the bloodstream. It uses extremely fine aerosol particles that can penetrate to the lungs' tiny sacs—the alveoli—where the blood exchanges carbon dioxide for oxygen. For drug delivery to be effective, spray droplets must be "in the range of a few microns," explains Rob Clark, the company's principal mechanical engineer.

The device now in clinical trials can be held in one hand and uses disposable strips holding 50 microliters of insulin solution encased in a blister of laminated plastic. The disposable strip features a laser-machined nozzle, which has extremely fine holes that will separate the liquid drug into a mist of tiny droplets. An electrically actuated piston sends the liquid through the nozzle's holes and into the patient's lungs.

The user simply has to breathe through the inhaler, and the device's differential pressure transducer detects when the patient's breathing is most receptive to the medication and automatically actuates the piston. Prior to taking the medication, the user can set the dosage, which is electronically controlled.

Aradigm is planning to use AERx technology in other medical applications, including delivering opiates, testosterone for post-menopausal women with diminishing libido, and drugs for hepatitis and some cancers. The company has already outlined a new, smaller version of the product in clinical trials and designed a mechanical version that would forgo batteries.

Watch Out, Eye Drops

Like inhalers, contact lenses are also gaining utility. In addition to improving vision, contact lenses could soon administer medication, making eye drops obsolete. Developing this new technology are researchers at the University of Florida, who say that this new drug delivery system offers four major advantages to contact lens wearers.

According to Anuj Chauhan, PhD, the project's leader, one main benefit is reducing side effects, such as heart problems, which can result when using eye drops because the drugs in the drops can seep into the nasal cavity and then into the bloodstream and other tissues. Additionally, the new drug delivery method enables greater compliance, lowered drug consumption and the administration of a steady dose, which will stay in the eye, instead of a single large quantity, followed by diminishing drug levels that are ineffective. The new technique could also potentially convey antibiotics, protecting lens wearers from bacterial infections.

"One of the biggest problems with using eye drops to deliver medication to the eyes is that about 95% of the medication goes where it's not needed," says Chauhan. "Our approach allows us great flexibility in designing controlled drug-delivery vehicles that can be tailored to different drugs, but are also effective for extended periods of time." In fact, users can wear the lenses for up to two weeks while they administer controlled doses to the eyes, according to researchers. Chauhan estimates that the new system could be ready for commercial introduction within about 7 years.

For this delivery mechanism to be effective, the drugs are embedded in nanoparticles that are then integrated into the contact lens matrix during manufacture. This approach differs from previous endeavors to develop drug-delivering contact lenses, which entailed immersing them in a drug solution or enclosing the drug in a cavity between two pieces of lens material. The researchers say such methods are only temporarily effective.

In contrast, the new technique works over a longer period of time. When placed on the eye, the lenses let the drug diffuse from the nanoparticles through the lens matrix and into the thin film between the lens and the cornea. The drug stays in the film for an extended period of time, longer than drugs administered via drops, which only linger for about two minutes.

Sources: Air Passage
Mechanical Engineering, May 2003
http://www.memagazine.org/

Making Needles Pointless
John George
Philadelphia Business Journal, May 12, 2003
http://philadelphia.bizjournals.com/philadelphia/stories/2003/05/12/story6.html

Contact Lenses Used to Deliver Eye Drugs
Medical Device & Diagnostic Industry, May 2003
http://www.devicelink.com