An EpiPen Product Teardown

As far as autoinjectors go, the EpiPen® could be considered the most famous, and the most dominant in today’s market. So, when was the EpiPen invented? How do you use an EpiPen? What is the EpiPen made of? How does the EpiPen work and, how can the EpiPen be improved?

As part of his induction at Haughton Design, Graduate Design Engineer, Rob was tasked with tearing down an EpiPen, reviewing its function, reverse engineering it and remodelling it in SolidWorks. Here’s his journey and findings:

Upon First Inspection

The EpiPen comes in a protective carry casing. This case is made of a strong impact resistant plastic that comfortably absorbs any impacts or shocks from everyday use (drops, squeezing etc). The case is simple to open (can be opened one handed) and the EpiPen® itself slides straight out. Once the EpiPen is in hand, you notice the Instructions For Use (IFUs) placed on the outside. The IFUs are bright in color and detail the 3 main steps for safe and effective use. You initially notice how color has been used to signify danger (orange) and calm (blue) to indicate which end is safe to handle.

What is an EpiPen made of?

So, for these simple steps to be enabled, what’s in an EpiPen®, how is an EpiPen made and, what are some of the EpiPen’s design requirements? We conducted a teardown to isolate the individual components:

How does an EpiPen work mechanically?

Step 1:

Step 2:

Step 3:

How can the EpiPen be improved?

Naturally, the device has been optimized to function adequately with the fewest components possible. For example, the control tabs are used to perform 3 actions; locking the protective sheath, releasing it after firing, and preventing the needle from retracting. The needle cover has three functions; keep the needle clean, prevent adrenaline leaking and also working as a shock absorber. As manufacturing capabilities advance, it will be interesting to see how this affects the number of components that are used.

Colour is used well to denote what is safe and what is dangerous. However, a 2014 study found that of a sample of 100 adults, only 16 were able to perform all steps correctly. This may in part be due to association, people using previous experience to inform use of new products and medical devices. For example, association with the clicky pen – it has button at the top that you press for the pen to be released. Thus, new users look for something they can press – on the EpiPen®, it is the orange shroud. In situations where there is time to read the instructions before administering the dose, once learned, the user steps are very simple. If someone is panicking, will they read and comprehend the instructions? This also goes for the date indicator, the responsibility is on the patient (as they carry it), is someone without training always going to check the indicator when someone needs adrenaline?

In conclusion, EpiPen® formed the foundation for what an AAI can do. Mechanically, this device is very well optimised. Usability wise, there are definite improvements compared to the older versions. Other AAI’s such as Jext or Emerade in the UK have been developed to overcome some of the issues with the EpiPen® but for one reason or another, the EpiPen® has stood up to the competition. EpiPen® is a cleverly designed device – we hope that this breakdown of the device has been insightful. Please get in touch to discuss how Haughton Design can help with your drug delivery device development.

EpiPen® is a registered trademark for Mylan Pharmaceuticals (now part of Viatris).