Overcoming obstacles to enhance the viscous injectable administration experience

As we have discussed in previous insights, there are several challenges hindering the widespread adoption of self-administration for highly viscous formulations, for example some biopharma treatments.

First of all is the potential impact of viscous drug formulations on patient experience. Existing auto-injector devices using traditional spring-powered mechanisms are not able to deliver the formulation through a small-diameter needle, as the pressure required could break the device. To circumvent this, a wide-diameter needle must be used, but many patients find these uncomfortable or even painful. This can make them unwilling to take their treatment, leading to poor patient adherence.

Secondly, there are challenges developing and manufacturing viscous formulations that are more patient friendly for example by reducing the likelihood of adverse side effects or improving bioavailability. For example, diafiltration is a process with the potential to enhance the concentration of the active pharmaceutical ingredient (API) to mitigate against delivery challenges by reducing the amount of formulation needed per dose. This process however can bring stability and aggregation problems, which can impact on the quality and effectiveness of the product, as well as its shelf life. Diafiltration can also pose saleability issues, which can undermine commercialisation of new products.

Breaking down barriers to adoption

Overcoming these issues can be daunting for drug companies and may also lead them to believe that their options are limited when it comes to designing more patient-friendly parenteral drug products for self-administration.

However, this is simply not true. Steps can be taken not only to overcome manufacturing efficiency issues, but also useability issues for patients to enhance the effectiveness of the delivery device used for viscous medications. Taking these measures can play a key role in delivering a better experience for patients, regardless of whether effective changes to the formulation can be found.

The key issue with standard injection devices is that viscous formulations need to be administered with relative ease and cause limited pain. Traditional syringes are only able to deliver viscous formulations by using a needle with a wider diameter, as this can significantly reduce the pressure required to deliver the drug.

Wide-diameter needles can be unpleasant for patients, particularly if they are self-administering, as they do not have the training of a healthcare professional to mitigate against the potential discomfort. This can result in a poor patient experience, impacting on patient compliance.

Advances in technology

However, thanks to innovations in injectable device technology, there are ways to address this issue and improve patient experience when administration takes place outside of the clinical environment.

A key innovation that has the potential to transform viscous formulation delivery is the development of devices that use a liquefied gas, rather than a spring, to push the formulation through the needle. This propellant allows even greater pressure to be exerted to push the drug through a fine needle, while minimising the risk of the needle breaking, the device stalling or causing undue discomfort for the patient. This effectively eliminates the need for the inclusion of unpleasant wide-diameter needles.

Another advancement in technology involves changes to the design of the primary formulation container. Standard glass prefilled syringes can be susceptible to cracking when high pressures are applied to deliver a viscous drug formulation. Recent improvements to container design have significantly reduced the likelihood of this happening.

For example, polymeric primary containers, such as those based on cyclic olefin polymer and copolymer (COP/COC) can better withstand the pressures experienced during the administration of viscous drugs. However, there are concerns with stability and leachables for some products, which means they are not yet a universal solution to the problem of drug container breakage.

Innovation key to enhancing the patient experience

As the number of viscous biologic formulations available on the market grows, it will become ever more important to keep patient-centricity front of mind, particularly for self-administered drugs.

While there are limitations in terms of how far we can improve the formulations of drugs to reduce their viscosity, there are many opportunities to enhance the design of the devices that deliver the finished formulations to optimise the patient experience for viscous formulations.

By working with specialist third-party device experts, like Bespak by Recipharm, drug companies can benefit from comprehensive support in developing more useable, patient friendly injectable treatments. As a result, they can be confident that they have the help and guidance they need to overcome the administration and manufacturing challenges of viscous injectable drug formulations, so they can deliver a better experience for patients.