User-Centric Approach to Specifying Technical Attributes of Drug Delivery Devices: Empirical Study of Autoinjector-Cap Removal Forces

Abstract

Purpose The subcutaneous delivery of biologics using pre-filled autoinjector devices continues to attract broad scholarly interests. However, research still lacks a detailed understanding of user perceptions as the basis for specifying the clinically relevant technical attributes of a device, such as the cap-removal force. Therefore, this article studies the ability of users to remove the autoinjector cap, as well as the effects of the cap-removal force and user characteristics on the perceived ease of decapping. Patients and Methods Forty-two participants among patients, caregivers, and healthcare professionals removed the protective cap using non-functional devices with different target cap-removal forces between 25 N and 55 N. Data were collected on the ability of the users to effectively decap the device and their perceived ease of decapping. Linear regression was then applied to quantify the impact of the decapping force and patient characteristics on the perceived ease of decapping. Results The participants of the study effectively decapped all autoinjector devices irrespective of age, sex, and dexterity impairments. Moreover, the study reveals that the perceived ease of decapping decreases significantly with increasing decapping force and participants’ dexterity impairments. Conclusion The study provides initial empirical evidence on the ability of users to decap autoinjector devices and shows how increasing the cap-removal force and dexterity impairments reduce the perceived ease of decapping.

Autoinjector Design Parameters: A Human Factors Perspective

“…One exception is a study by Schneider et al (2021) that evaluated an autoinjector platform, with magnet-instrumented mockups to simulate cap removal forces of 25N, 35N, 45N, and 55N (Schneider et al, 2021). The study was tested across a wide range of populations and found that all participants were able to de-cap the devices up to 55N (Schneider et al, 2021). However, authors of the paper did note that despite the successful task completion, some participants struggled with the task.…”

Quantifying Patient Capabilities and Setting the Stage for Future Development: Insights from a Sensor-Augmented Simulated Use Study with Pen Injectors

“… 24–26 Secondly, appropriate handling forces improve the accessibility of emerging self-care treatment options to a diverse user population. 27 This aspect is essential in the current era of self-injection device platforms. 2 , 11 , 12 The industry is adopting pre-engineered technologies to serve multiple target patient populations, including those with varying levels of strength and dexterity.…”

“… 28 Inappropriate handling forces can lead to use-related errors and jeopardize patient safety. 17 , 27 Thirdly, meeting the stringent regulatory standards for self-injection devices is critical to obtain regulatory approval and a prerequisite for successful market adoption. 29 , 30…”

“…Researchers have recently started studying the situational actions and use-related forces involved in patients’ interaction with autoinjector technology. 27 , 31 These efforts provide a more nuanced understanding of the drug self-administration process. For instance, researchers have integrated motion and force sensors directly into autoinjector devices and accessories to analyse user behaviour for each handling step.…”

“…Schneider et al have addressed this shortcoming by using non-functional autoinjector prototypes with different predefined discrete force levels to assess the patient’s ability to remove the protective needle cap from an autoinjector. 27 The approach described allows for a realistic handling sequence but does not provide continuous force data beyond the predefined force levels. Another approach that has been used involves adding force sensors to an injection pad, suitable for studying the patient’s ability to press the autoinjector device against the skin.…”