Despite consumer demand for needle-free methods of drug delivery, the traditional injection remains the dominant paradigm, and prefilled injection devices, which are quicker and easier to use and enable premeasured and presterilized dosing, are being increasingly integrated into the plans of pharma and biotech companies. According to a report from Greystone Associates, prefilled syringes are replacing vials both in terms of injections and sector revenue, and as this trend continues during the next 4 years, the number of tailored injectable drug products reaching the market is set to escalate.

But this doesn't mean that integrating this technology will be easy. One of the major issues is stability. In an exclusive interview with Pharmaceutical Technology Europe, David Clark, Market Analyst at Greystone Associates, explained the problem. "Unlike glass vials, the drug needs to be stable for protracted periods of time while in contact with the different synthetic materials that comprise the syringe. Therefore, stability testing is a big necessity."

However, drug stability is improving as advances are made in the design of prefilled syringes, such as new materials and manufacturing processes. Advances are also being made in the field of needle-free injections, but although Clark said these would "play a part" in the sector he also added: "the major movement will be within the injectable device sector; from syringes to pen injectors and auto injectors."

The use of prefilled injection devices varies depending on the drug class. "For example, recombinant protein drugs are very expensive to manufacture and are, therefore, almost always available in prefilled syringes," said Clark. "This is more economical than having to overfill vials to account for caregiver variations or eliminating air bubbles in the syringe prior to injection, etc." He also adds that vaccines, which are relatively less expensive, are also supplied in prefilled syringes because it saves time when vaccinating large numbers of patients. "This is a major advantage in undeveloped areas such as sub-Saharan Africa where vaccination is essential to improving quality of life and reducing the incidence of disease."

And how does Clark expect the sector to grow during the next few years? "A greater percentage of drugs in a given drug class will become available in prefilled syringes," he said. "In particular, this relates to drugs indicated for chronic conditions; self-administration will also become available in automated injection devices."

www.greystoneassociates.org