PharmTech : Injectable devices used by a patient at home are an important development in increasing patient compliance. What are noteworthy advances in the design of such devices?

Reynolds: Many complex diseases and chronic conditions such as multiple sclerosis, rheumatoid arthritis, and anemia require home-based administration of injectable treatments. This need has spawned increased interest in drug-delivery systems that are safe, convenient, and help simplify drug administration, especially for nonhealthcare professionals. Autoinjectors are a convenient delivery method for drugs and biologics. They can ease drug administration for patients who must self-inject and who may have dexterity issues that impact their ability to use a syringe.

Patients who use injection devices at home are concerned with several issues. They want a device that is easy to use, offers audible, tactile and visual evidence that the drug has been fully delivered, and safely and automatically inserts the needle and retracts it after injection. These are among the critical success factors that should be considered for an autoinjector system. The compatibility between the autoinjector and the syringe is also an issue. Glass syringes may be problematic for certain uses. The flexibility of a COP syringe may be a better choice for an autoinjector system because COP syringes offer better control of dimensional tolerances and more consistent functional performance, especially when provided without the added variability associated with uneven siliconization.

Reynolds: Given that many biologics, through their nature, are most effectively delivered by injection, the focus has been on optimizing the injection experience for the patient or caregiver. This process involves minimizing preparation steps, providing convenience kits with all necessary components included, and providing the drug within a ready-to-inject disposable format.

A good example of product life-cycle extension is shown in the evolution of the drug Enbrel (etanercept), which was initially launched as a lyophilized product in a vial. The first evolution was to provide a reconstitution kit, which simplified the preparation process. Subsequently, a liquid form was introduced in a prefilled syringe, and then a disposable autoinjector was added. Through this evolution, the patient experience was enhanced. In many cases, this evolution is dependent upon an effective combination of the drug container and the delivery device to ensure the stability of the drug and ease of administration, and requires an integrated approach. Such an evolution can help differentiate a drug in a crowded market.

PharmTech: Looking into the future of injectable-drug delivery, what do you see as possible noteworthy developments during the next 5 or 10 years?

Reyonlds: We expect that more injectable biologic drugs will be approved and come to market, which will drive the need for convenience of administration. There will be longer-acting, higher-viscosity drugs requiring less frequent doses that will present new manufacturing and administration challenges. With more challenges to the developers of these products, cleaner, safer, and more reliable packaging systems, such as syringes or vials manufactured from plastic materials that can be combined with fluoropolymer-coated elastomer components, will increase.

Increasing self-administration will drive the development of new injection devices, with capabilities to handle higher viscosity materials while providing an improved patient experience. More emphasis will be placed on optimizing devices for various patient groups, while building on a platform technology suitable for drug manufacture and filling.

Product life-cycle management will continue with increasing emphasis on maintaining drug stability and effectiveness through each stage. This will lead developers to seek novel materials, which can be utilized early in the drug-development cycle through to a variety of containment systems, including vials, syringes, cartridges, and novel containers.