Patient-Centric Design

Departments - Features

The Increasingly Important Role of Human Factors in Designing Drug Delivery Systems

December 3, 2012
Raza Ahmed, MD

Self-administration systems can potentially be an integral tool in maximizing the therapeutic action of drugs, but only when they are appropriately designed. Self-administration systems offer convenience by allowing patients to administer physician prescribed medications in their preferred setting. The design of a self-administration system is important, because it can increase safety, ease of use, and comfort. The design can thereby help patients feel at ease in the administration of their treatment, increasing the likelihood that they will be compliant. Selecting a self-injection system is therefore a big decision for drug developers and manufacturers –a lot is at stake, as an incorrect decision in system selection could potentially compromise the drug’s success.

There is a lot of attention on self-administration systems today. Home healthcare has become an area of increased focus around the world – in the United States, for example, according to the IMS Health’s 2011 National Health Perspective, home healthcare grew by 8% from the prior year to represent a $2.8 billion retail channel. The continuing shift to outpatient care, along with the introduction of new injectable therapies, has resulted in a significant increase in the use of self-administration injection systems in recent years. These systems are now widely used in outpatient care in the treatment of diabetes, rheumatoid arthritis (RA), infertility, multiple sclerosis (MS), and many other diseases that affect large populations.

When selecting a system for drug delivery, it is imperative that the end user can use the system successfully. A patient-centric design model can help maximize the opportunity for a self-injection system to be used successfully. Just as therapeutics have specific mechanisms of action; systems aimed at self-administration must be designed specifically for the end users. It is therefore important to understand human factors – “a body of knowledge about human abilities, human limitations, and other human characteristics that are relevant to design”¹ – when designing a drug delivery system. Depending on the disease state, the human factors that need to be considered will change; patients may have different degrees of limitations, furthermore, patients with the same disease state may have varied levels of impairment during the progression of the disease, and co-morbidities must also be considered.

Human factors engineering is the application of human factors to design the machine-human interface and can be defined more fully as “the application of human factors information to the design of tools, machines, systems, tasks, jobs, and environments for safe, comfortable, and effective human use.”1 This is often referred to as ergonomics or usability engineering. A strong capability in human factors engineering is a key component of any patient-centric design approach.

Regulators are increasingly emphasizing the importance of usability in medical device safety. Human factors studies are often required for approval of medical systems in the U.S. and EU. In 2011, the Center for Systems and Radiological Health (CDRH) at the U.S. Food and Drug Administration (FDA) issued draft guidance on the consideration of human factors in medical device development and testing. The guidance “provides recommendations for medical device design optimization through human factors analysis, testing, and validation. The intent is to improve the quality of the device user interface such that errors that occur during use of the device are either eliminated or reduced.”²

The recommended process includes formative usability testing starting with the exploratory stage of the device and continuing through all stages of conceptual design. Testing should include assessment of alternative design options as well as comparisons with competitive products. Validation testing is conducted as a final stage of the process and is performed with real users. The FDA recommends that validation testing be performed in a simulated user environment that challenges all key aspects of a product’s design and that reflects the level of product-use training end-users are likely to receive. To meet these standards, many pharmaceutical manufacturers and drug delivery system companies will need to reposition product design and engineering platforms to focus more on the relationship between the patient and the delivery system.

The Approach
BD’s purpose is “Helping All People Live Healthy Lives.” The company has more than 100 years of experience developing medical technologies to address healthcare problems and, along the way, has established a patient-centric culture that flows through to the product design approach used today. The people at BD realize that while home healthcare can offer patients new levels of treatment conveniences, there must be a greater focus on understanding the usability of the system and the human factors that impact this. Human factors engineering has long been used by automotive and computer manufacturers, with companies such as Apple and BMW being prime examples; however it has only recently gained traction in the medical system industry. Because of the company’s long history, established capabilities, and patient-centric approach, BD is at the forefront of this movement.

BD has a global team of medical experts to design studies that focus efforts to address human factors while integrating a broader range of usability and ergonomic studies for our self-injection systems. BD also have established relationships with leading human factors experts around the world to ensure the company is on the cutting-edge of the current human factors engineering thought process. BD proactively and independently funds studies to ensure that the highest quality human factors research is a component of the final product that our partners put into the hands of patients.

When BD engineers develop a self-injection system or modify an existing one, they undertake multiple types of patient research and studies – all designed to uncover unmet patient needs and directly address usability and human factors concerns. A key part of this approach involves subjecting the system to several rounds of usability testing. This testing allows engineers to put the representative system into the hand of the representative user. Participants simulate use by following an Instruction for Use (IFU), with careful observation of how these patients react, as well as capturing their initial response on a variety of parameters, including the look and feel. After each round, information is presented to the R&D teams in order to, potentially, make design changes to mitigate patient errors. Further, BD makes appropriate changes to the IFU in order to mitigate errors from occurring.

Human Factors in Action
An excellent example of a product optimized for patient use is BD’s disposable pen, BD Vystra™. This pen is not yet commercially available, but has already under-gone several full formative studies with patients representing both experienced and inexperienced users across three different disease states. Testing of more than 20 features or functions of the pen occurred, along with the IFU, resulting in a product shown to be acceptable to end users. This was just the culmination of a much longer patient-centric design approach that includes interviews with more than 200 current pen-injector users across the globe, ergonomic analysis by leading human factors engineering experts, and a multitude of early-stage studies.

An example of commercialized self-injection product, where human factors engineering played a key role in its success, is the BD Physioject™ disposable autoinjector. The design of this product is for use in the treatment of chronic disease such as rheumatoid arthritis, multiple sclerosis, and osteoporosis. It is a single-use, disposable autoinjector that incorporates the 1mLL BD Hypak™ glass prefillable syringe to perform automatic injections in fixed doses. The system has several features that promote patient safety and ease of use. These include:

  • A 360° view of the drug and injection process that allows the patient to confirm full dose delivery,
  • A one-touch injection button,
  • A hidden needle before and during injection to reduce needle stick anxiety, and
  • A protected needle before and after injection to reduce the risk of needle stick injury.

The design allows the patient to control the start of the injection once the autoinjector is placed on the skin and the cap is removed.

Optimized for ease of use, comfort, and reliability through rigorous ergonomic and quality assessments – to ensure an intuitive user experience – is the BD Vystra Disposable Pen.
• NOTE: Pictured is a look and feel design concept. Additional ergonomically optimized look and feel options are available.

To support the development of the BD Physioject disposable autoinjector, the company conducted multiple human factors studies to assess all aspects of performance safety, efficiency, patient acceptance, and ease of use, including pain perception versus prefilled syringes. The studies provided essential insights regarding the user-product interface and showed that patients had a very strong and positive response to both the product design and the user experience. Based on these studies, fully two-thirds of patients indicated they would prefer the BD Physioject system to their current autoinjector*.

In many cases, insights found in testing prompted the company to conduct substantial additional testing in key areas. For example, when the research teams found that an autoinjector with a small diameter was difficult to grasp for RA patients with limited manual dexterity, BD completed the necessary additional testing to refine the design to improve the user interface to address this issue.

On the horizon

To continue maintaining the highest standards in addressing human factors issues, drug and delivery system manufacturers must work in close partnership. This is required to structure and execute the testing protocols that can identify the widest possible range of issues that can affect the user experience. Pharma companies are looking to delivery system partners to have established human factors engineering expertise, and to have conducted independent, high quality research to demonstrate system usability. Furthermore, with global regulation requirements concerning human factors currently changing, a delivery system partner should be able to offer up-to-date guidance and support to meet these requirements.

At BD, given the patient-centric mindset and global human factors engineering expertise established through more than 100 years of medical system development experience, the company is ideally positioned to be the partner of choice when it comes to human factors. By helping pharma partners address, appropriately, human factors concerns, not only are they more assured of success, but also together, helping more people live healthy lives.


Franklin Lakes, NJ

¹From the article by Alphonse Chapanis, “To Communicate the Human Factors Message, You Have to Know What the Message Is and How to Communicate It,” Human Factors Society Bulletin , Volume 34, Number 11, November 1991, pp 1-4:

²Draft Guidance for Industry and Food and Drug Administration Staff - Applying Human Factors and Usability Engineering to Optimize Medical System Design. June 22, 2011.

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*Data on File at BD