Why Have Insulin Jet Injectors Never Really Caught On?

February 18th, 2011

An insulin jet injector sounds like a great idea. Intended to be a less painful way of delivering insulin than the traditional insulin syringes or insulin pens, they deliver a fine jet of insulin under such high pressure that it is able to penetrate the skin without a needle.

The first insulin jet injector, dubbed the "peace gun", was invented by a doctor in the 1940s for mass immunization of American troops. It was used right up until 1997, when it's use was discontinued because of concerns around cross-contamination from multiple users. According to all reports, the peace gun was efficient, but painful.

The jet injector was first offered for individual use in 1979. A modern insulin injector looks similar to an insulin pen, but larger. There are a number of different models, but the typical insulin injector consists of three pieces - a metal pen-like delivery device, a disposable plastic nozzle, and a disposable adapter to connect the injector to an insulin vial. The insulin injector has a dosing dial that allows individual users to select their correct dosage.

The metal injector is designed to last for years, and the detachable nozzle and adapter are intended for multiple uses before disposal. The air pressure is created by either a powerful spring device or a nitrogen or cartridge dioxide cartridge. The devices have adjustable pressure settings so users can select the one that is most effective while causing them the least discomfort.

There are some obvious benefits to a needle free jet injection system, the most apparent being the option for the needle phobic to avoid needles. Other advantages are the speed and ease of use, safety (no bent or broken needles, or "sharps" to dispose of ), less risk of contamination, a better spread of insulin into the subcutaneous tissue, no scar tissue build up at the injection site, and no need to keep buying syringes.

So why do so few diabetics use them? The number one reason seems to be pain. Although some people find a needleless injection quite tolerable, many find the pressure required to force the insulin through the skin most uncomfortable. It's not uncommon for the skin at the injection site to bleed, swell and/or bruise.

Another major factor is the initial cost (at least several hundred dollars) although this is offset by the fact that users don't have the ongoing expense of syringes. Not all insurance companies cover the cost of an insulin injector, and many of those that do require a letter from your doctor.

Jet injectors are also more cumbersome and less portable than insulin syringes or insulin pens, not just because they're larger and heavier, but also because users also need to carry an insulin vial (which requires refrigeration), the adapter and, with some models, the nozzle along with it.

It takes more time to set up an insulin injector than it does to fill a syringe. Unlike a syringe or insulin pen, an insulin injector requires maintenance, and has to be taken apart and sterilized on a regular basis. Some people are put off by the noise made by the compression system during use.

There are insulin injectors specially designed for use in children, and even one for dogs and cats, the Zoe Pet Jet. Those who have managed to find a comfortable setting on their jet insulin injector seem quite happy with the devices, and urge new users not to give up if they're not initially comfortable using one.

Insulin Therapy Changing With New and Improved Insulin Delivery Methods

April 14th, 2011

An old insulin syringe
Not that long ago, being insulin dependent meant you had to carry around a syringe and a vial of insulin to deliver your insulin injections, making sure to keep them refrigerated. There are now a variety of methods for insulin delivery on the market, and some promising new developments on the horizon. These include:

1) Insulin pens. Most types of insulin are now available in convenient prefilled pens. Some insulin pens are entirely disposable when empty, and others use a replaceable insulin cartridge, usually containing 300 units. There is a dial on one end to set your desired dose. The pens offer discreet, push button insulin delivery. Some claim the injections are more comfortable than from a needle that has already been dulled by insertion into an insulin vial. Many people prefer to use an insulin pen if they are caring for a diabetic child or pet.

2) Insulin pumps. Insulin pumps are a device about the size of a pager that adhere to the skin and are worn 24/7. Insulin pumps contain an insulin reservoir, a battery powered pump, and a programmable computer chip that allows the user to control insulin dosing.

The pumps is attached to a thin plastic tube called a cannula, which is inserted just under the skin to deliver insulin subcutaneously and continuously. Insulin pump technology is constantly being improved upon. The newer pumps are smaller, and can "communicate" and interact with a continuous blood glucose monitor and computer software for state of the art blood sugar control.

3) Insulin jet injectors. Insulin jet injectors deliver a fine jet of high pressure insulin directly through the skin. The main advantage is that that the insulin delivery system requires no needles. The major disadvantage is that many diabetics find the force required for the insulin to permeate the skin is painful, and may cause bruising. Jet injectors have been on the market since 1979, but have yet to become popular.

4) Insulin patch. The FDA has just approved a new insulin delivery patch. The new device, Finesse, is a small plastic patch-pen roughly 2 inches long and an inch wide that is attached to the skin like a bandage. It can be worn under your clothes, and remains attached during routine activities like sleeping, exercising and even showering.

Patients use a syringe to pre-fill the patch-pen with a three-day supply of insulin, and simply push two buttons to dispense a dose of fast-acting insulin when needed. The insulin is delivered in seconds through a miniature, flexible plastic tube inserted painlessly into the skin. The manufacturer, Calibra is also working on a patch-pen that would deliver a .05 unit insulin dose for children.

5) Inhaled insulin. The FDA approved the first insulin inhaler, Exubera, in 2006. It was a short-acting insulin delivered to the lungs through a device similar to an asthma inhaler. But it never achieved market success, and was discontinued a year later.

But research on inhaled insulin continued, and two new forms are poised to hit the market. One is an insulin inhaler, AFREZZA, which is awaiting FDA approval. The other is an insulin spray which is absorbed through the mouth, called Oral-Lyn. Oral-Lyn is in Phase 111 clinical trials in Europe and North America.

Despite some obvious advantages to the new insulin delivery methods, tried and true insulin syringes remain the most popular way to deliver insulin injections with most insulin dependent diabetics, who no longer consider injections a big deal.

Insulin pens, insulin pumps, and insulin jet injectors are all more costly than insulin syringes, and not always covered by medical insurance.Not all types of insulin are available in insulin pens, and you can't mix insulin types in a pen.

Insulin pumps can kink or otherwise malfunction, posing the danger of inaccurate insulin dosing, and are just too "high tech" for some diabetics. Many diabetics remain skeptical of devices like insulin inhalers and sprays after Exubera's spectacular lack of success.

Still, with the advances being made in insulin pumps, and the pending introduction of an improved inhaled insulin and the insulin patch, the world of insulin therapy is definitely changing - and most would say for the better.