Needle-free injections making their point

Using jet pressure and only taking 300 milliseconds, could needle-free injectors be the answer to ‘needle phobia’?

A patient’s fear of a visit to the doctors or dentists often stems from one thing - needles. To overcome this ‘needle phobia’ and other issues relating to needle injections, one area that has received considerable attention over the past few years is the needle-free injection. As the name suggests, the technology has been developed to alleviate the need for a needle to inject medications through the skin.

Needle-free injectors also offer an important choice to those people who have to face injecting themselves on a regular basis. Some people with diabetes have to inject themselves up to four times a day with needles to deliver insulin into the subcutaneous tissue where it can be absorbed into the body.

Sheffield-based company The Medical House (TMH) are at the forefront of developing needle-free injections. They began this year with an announcement of a £4.3 million agreement with global biotechnology leader Serono. A state of the art needle-free injector is being developed by TMH with development costs of £435,000 to be contributed by Serono. Under the five-year contract, TMH will manufacture and supply a reusable needle-free device, the GH-1, which will be used to deliver human growth hormone. In February TMH licensed the GH-1 for the delivery of Biopartners human growth hormone product Valtropin.

Needle-free injections began life for TMH in April 2001 when an agreement was signed with US company Bioject to develop and manufacture a new version of Bioject’s existing reusable needle-free drug delivery system, Vitajet, which has been marketed worldwide for 20 years. The result of that development was the mhi-500, which in November 2002 was listed on the NHS Drug Tariff, enabling it to be prescribed to patients free-of-charge, for self-administration of insulin. Today, the mhi-500 is the only needle-free injector that is available through the NHS.

TMH followed the mhi-500 with the development of their own spring-powered needle-free delivery system called the SQ-Pen. TMH say that the SQ-Pen “offers many advantages over existing needle-free systems including a less frequent nozzle change, only once every two weeks, making the device more convenient for users.” TMH developed the SQ-pen under a Comfort Optimisation Programme involving microscopic analysis of the nozzle configuration and jet profiling of the insulin shot. The resulting technology, they say, “has enabled the comfort of needle-free delivery to be brought to a whole new level.”

The SQ-PEN will be available worldwide through a network of international distributors. TMH already have agreements in place covering large parts of the world including China and Pakistan, which have two of the world’s largest diabetic populations.

Internal workings of the auto-safety injector. The needle remains hidden at all times and optimal insertion depth ensures a comfortale delivery.

Needle-free vs needle-based Needle-free injectors use jet pressure to inject the drug rapidly into the tissue at the correct depth. The jet is achieved by forcing the drug through a specially designed nozzle, which is completed in only 300 milliseconds. Giving an insulin injection with a syringe or a pen requires training and practice to ensure that the needle is correctly inserted to the right depth. A pinch up technique is usually advocated to avoid the risk of intramuscular injection. In addition, following injection the needle should remain in situ for 10 seconds to minimise the risk of leakage back through the puncture site. The needle position has then to be maintained during the injection and care taken to avoid needle-stick injury during withdrawal and disposal. With a needle-based system there is always the possibility of breaking a needle or injecting to the wrong depth. In those with diabetes for example, this can lead to poor glycaemic control, increasing the risk of developing complications associated with diabetes. Needle-free devices remove the need for sharps when injecting. Sharps disposal is an expensive business, both patients and healthcare professionals alike run the risk of needle-stick injury and when sharps are disposed of incorrectly, that risk becomes even greater. This combined with the claims culture that we live in today; sharps and their disposal could prove to be an important issue. Future developments Many drugs are unsuitable for delivery via a needle-free injection. TMH are taking all they have learnt about self-injection and applying it to a system that can accommodate a greater range of drugs. These involve not only needle-free but also a needle-based auto injector, the ASI (AutoSafety Injector). The ASI is a disposable needle-based delivery device that incorporates drugs in pre-filled syringe presentation. It provides a completely automated delivery process (needle insertion, drug delivery, needle retraction) which achieves a consistent outcome without the need for specialist expertise, making it particularly suitable for self-injection. Patients’ injection anxieties are also addressed as the needle remains hidden at all times and optimal insertion depth ensures a comfortable delivery. The needle retracts back into the unit after use, permitting a safe and easy disposal of the used ASI device. TMH are also developing a single-use disposable needle-free device. The SU-1 is suitable for any pharmaceutical partner licensee as it works with drugs in existing syringe, cartridge or vial presentations, and will avoid the need for long and costly re-packaging projects. TMH have also shown that needle-free is not just a concept for the human market. In 2004 they signed an agreement with Arnolds Veterinary Products, a division of Dechra Pharmaceuticals. Needle-free drug delivery will enable pet owners and vets to routinely administer drugs without the potential problems of needle-based injections. Another possible use of needle-free devices is in the field of dentistry where the current use of needles creates heightened anxiety among patients faced with the prospect of a visit to the dentist.

By Jason Brannan, Information services manager, Medilink.