This article is part of a special feature on injectables that was published in the February issue of PTE Digital, available at http://www.pharmtech.com/ptedigital0211.

Needle-free injection technologies have been developed for injecting liquid formulations, as well as injecting drugs and vaccines in a solid dosage form. To date, however, the uptake of these systems has been slow.

Several liquid jet injection technologies are available on the market including Ferring’s Zomajet 2 Vision, Merck Serono’s Saizen Cool.Click and Teva’s Tev‑Tropin Tjet, which are all human growth hormone products. Zogenix’s Sumavel DosePro is also available, which is a sumatriptan injection for treating migraines. These liquid jet injection products, however, are expensive compared with most auto‑injectors and pen‑injectors, which also have the added advantage of being easily used by patients at home. The key benefits of avoiding a needle and ease of use of a liquid jet injector do not outweigh the overall cost of goods compared with other delivery technologies.

Despite the obstacles, I believe that needle-free delivery systems will replace traditional needles, but only for certain applications such as growth hormone where there are already several needle‑free products on the market. For many drugs, I believe there will be a choice between one or more needle‑based injection systems, and one or more needle‑free systems as more products become generic and competition increases — in these circumstances, it is only the delivery system that really differentiates products. The human growth hormone market, for example, has several big players (Pfizer, Merck Serono, Genentech and Novo Nordisk) that offer multiple delivery technologies for human growth hormone. There are also other players in the market, including Eli Lilly, Teva and Ferring, with at least one human growth hormone product available.

Needles will probably still be used in the hospital environment and when used by trained healthcare professionals. When self‑injection is required or in environments when needles cause a particular issue, such as in pediatric applications, for example, there is a strong argument and need for needle‑free products. It is unlikely, however, that needles will ever be eliminated in any product applications, but needle‑free technologies will take a larger market share as they become more established. To achieve this, however, the technology will ideally offer product benefits to patients and healthcare professionals beyond ease of use and elimination of needles to help offset an increased cost of goods.

Solid dose injector technology

Our Glide SDI (Solid Dose Injector) enables the injection of APIs in a solid dosage form without the need for a needle. The drug is mixed with selected excipients and individual dosages are produced as tiny rods with a point at one end. A dosage is then pre‑filled into a single‑use drug cassette.

In use, the drug cassette is placed into a spring powered, handheld actuator. Pushing the end of the cassette against the skin target charges the spring in the actuator. At a preset spring force, the actuator automatically triggers, pushing the dosage from the drug cassette into the skin. The small, low cost drug cassette, which contains no sharps, can be safely thrown away and the actuator can be reused hundreds of times, resulting in low cost per administration.

Because the drug is administered in a solid dosage form, the Glide SDI offers enhanced stability and potentially avoids the need for refrigeration, as well as providing the opportunity for controlled release formulations by using slower dissolving excipients rather than fast dissolving sugars. In the clinic in volunteer studies, the Glide SDI has been overwhelmingly preferred to an injection with a standard needle and syringe.

A wide range of proteins, peptides and small molecules can be delivered using the technology. Preclinical studies with a range of antigens have also shown improved efficacy for vaccines in the Glide SDI when compared to a standard needle and syringe injection (data held on file at Glide Pharmaceutical Technologies Ltd).

Is the future needle-less?

Patients' want safer and better methods of taking their medicine. Additionally, with increased competition, pharmaceutical companies need new ways of differentiating their products and extending the patent life on proprietary drugs.

Many drugs and vaccines need to be administered parenterally, but there is limited scope for further new developments in the area of autoinjectors and peninjectors. As such, there will always be demand for new technologies, such as needle-free injection devices. Although they are currently viewed as being costly — which is one of the reasons the technology is not more widely used — the price of liquid jet injectors will fall as use increases. They may also be able to offer other liquid formulation benefits such as improved stability or controlled release. Although these benefits can also be offered by needlebased technologies, needlefree devices will also offer the benefit of ease of use and no needle.

The biggest advances in needlefree injection technologies will probably relate to their ability to inject solid dosage forms. The key challenge, however, will be the successful commercialisation of the first solid dose injection product to prove that the key perceived risks of manufacturing scaleup and regulatory approval for a novel drug delivery platform can be achieved.

Dr Charles Potter is CTO at Glide Pharmaceutical Technologies Ltd.