Improving the safety of disposable auto-injection devices: a systematic review of use errors

Understanding the interaction forces between shield-triggered autoinjectors and skin: an in-depth noninvasive study

OBJECTIVE

This noninvasive study aimed to understand the interaction between shield-triggered autoinjectors (AI) and skin at the point of activation, hypothesizing that the AI's housing absorbs a significant amount of the user-applied force depending on shield design and skin characteristics.

METHODS

Twenty-seven volunteers used a test device measuring applied force versus shield force and indentation depth relative to shield length (2,4,6,8 mm) in standing and sitting positions.

RESULTS

Significant differences were found between applied and shield force for the different shield lengths. Shorter shields resulted in significantly lower force transfer coefficients, with means ranging from 0.72 for the 2 mm shield to 0.94 for the 8 mm shield. ANOVA revealed statistically significant factors (p < .05), including position and gender, with females generally having lower coefficient values. Indentation depth increased with higher forces and varied significantly between positions without significant shield length impact.

CONCLUSION

The findings confirm that an increase in shield length at the point of activation reduces skin friction with the housing, resulting in less force loss and a lower device activation force perceived by the user. Force loss can be further reduced by standing up. Understanding device-tissue interactions will support development of better AIs with fewer user failures.

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

Background

While formative and summative usability testing is essential to confirm safe and effective product use, it may not be sufficient to comprehensively understand user capabilities and limitations in device interactions. Therefore, this research aims to quantify user handling forces for different device handling steps of pen injectors through sensor-augmented simulated use studies.

Research Design and methods

The study involved 46 participants who were divided into two groups: a healthy control group and a group of users with dexterity impairments. All participants were instructed to perform simulated handling steps using non-functional dummy devices equipped with force and torque sensors. Each handling step was performed twice: first at what participants considered a comfortable force level and then at their maximum force. The study then analyzed force data to investigate the impact of user characteristics and device geometry on force exertion during the different handling steps.

Results

The study demonstrates differences in the perceived comfortable and maximum force levels between the control and patient groups. These force levels decrease slightly with the user's age and level of dexterity impairment. Furthermore, the forces applied by the users are dependent on the geometry of the device and the holding pattern.

Conclusion

The results highlight the significance of sensor-augmented simulated use studies as a tool for providing quantitative insights into users' ability to exert force while handling self-injection devices. These data offer comprehensive insights that inform the definition of performance requirements and specifications for injection device design, thereby supporting the advancement of future self-injection devices.

Detectability of use errors in summative usability tests of medical devices: Impact of the test environment

The regulations on summative usability evaluations of medical devices (MDs) emphasize that the test environment must have sufficient ecological validity for generalization to real-life use. Here, we examined the influence of environmental fidelity (a component of ecological validity) on the detectability of MD use errors. A total of 140 participants participated in a summative usability evaluation of an anaphylactic shock auto-injector device under either a high-fidelity condition or a condition acceptable from the manufacturer's perspective, lower-fidelity condition. The numbers of errors detected in each condition were compared by applying descriptive statistics and logistic and Poisson multivariate regressions. We found that the level of fidelity did not influence the overall number of use errors detected but did influence the detection of certain use errors. To optimize the test environment and increase the detection of use errors, each environmental feature's role in the test task should first be examined.

Towards more tolerable subcutaneous administration: Review of contributing factors for improving combination product design

Subcutaneous (SC) injections can be associated with local pain and discomfort that is subjective and may affect treatment adherence and overall patient experience. With innovations increasingly focused on finding ways to deliver higher doses and volumes (≥2 mL), there is a need to better understand the multiple intertwined factors that influence pain upon SC injection. As a priority for the SC Drug Development & Delivery Consortium, this manuscript provides a comprehensive review of known attributes from published literature that contribute to pain/discomfort upon SC injection from three perspectives: (1) device and delivery factors that cause physical pain, (2) formulation factors that trigger pain responses, and (3) human factors impacting pain perception. Leveraging the Consortium's collective expertise, we provide an assessment of the comparative and interdependent factors likely to impact SC injection pain. In addition, we offer expert insights and future perspectives to fill identified gaps in knowledge to help advance the development of patient-centric and well tolerated high-dose/high-volume SC drug delivery solutions.

Pharmaceutical and biotech industry perspectives on optimizing patient experience and treatment adherence through subcutaneous drug delivery design

Subcutaneous (SC) drug delivery can be a safe, effective alternative to the traditional intravenous route of administration, potentially offering notable advantages for both patients and healthcare providers. The SC Drug Development & Delivery Consortium convened in 2018 to raise awareness of industry challenges to advance the development of patient-centric SC drug delivery strategies. The SC Consortium identified better understanding of patient preferences and perspectives as necessary to optimize SC product design attributes and help guide design decisions during SC product development. This manuscript provides a comprehensive overview of patient-centric factors for consideration in the SC drug delivery design and development process with the aim of establishing a foundation of existing knowledge for patient experiences related to SC drug delivery. This overview is informed by the outcomes of a multi-step survey of Consortium members and key pharmaceutical stakeholders. Framed in the context of the patient's treatment journey, the survey findings offer future perspectives to fill data gaps to advance patient-centric SC drug delivery.

Microfluidic Delivery of High Viscosity Liquids Using Piezoelectric Micropumps for Subcutaneous Drug Infusion Applications

Goal: Auto-injectors for self-administration of drugs are usually refrigerated. If not warmed up prior to the injection, ejection of the total drug volume is not guaranteed, as their spring and plunger mechanism cannot adjust for a change in viscosity of the drug. Here, we develop piezoelectric micro diaphragm pump that allows these modifications possible while investigating the effectiveness of this alternative dosing method. Methods: The dosing of highly viscous liquid of 25 mPa·s is made possible using application-specific micropump design. By comparing the analytical with experimental results, the practicality of the concept is verified. Results: Using a powerful piezoelectric stack actuator, the micropump achieves high fluid pressures of up to (368 ± 17) kPa. In order to assess the influence of viscosity, we characterize the fluidic performance of the designed micropump through 27G gauge needle for various water-glycerin mixtures. We find maximum flow rates of 2 mL/min for viscosities of up to 25 mPa·s. Conclusions: The developed micro diaphragm pump enables the development of smart auto-injectors with flow rate regulation to achieve drug delivery for high viscosity drugs through 27G needles.

The Reliability of Auto-Injectors in Clinical Use: A Systematic Review

Auto-injectors are medical devices designed for the self-administration of injections by patients and for easy administration by healthcare professionals in emergency situations. Although they vary in design and application, auto-injectors are typically built around a spring-loaded syringe. Despite their widespread use in a variety of clinical settings, there have been limited attempts to assess their reliability. This systematic review investigates the reliability of auto-injectors, identifies common causes of failure, and summarizes the overall rate of malfunction. A systematic review of research published on the PubMed and Cochrane Library databases was performed in July 2022. The relevant studies were assessed for their methodological quality and risk of bias prior to extracting key study outcomes on auto-injector reliability. Finally, a summary rate covering all eligible studies was calculated.  The search identified a total of 110 articles, of which ten were found to be suitable for inclusion. The risk of bias was low, and the methodological quality was high across the ten studies. Out of a total of 2,964 injections administered from an auto-injector, there were 12 device malfunctions, giving a summary rate of 0.40% (±0.23) auto-injector failures. The causes of malfunction varied in nature, with the majority of cases (58.3%) not being specified or not identified. This review has demonstrated that auto-injectors are reliable devices. Although further research on the nature of malfunctions is needed, the low rate of malfunctions supports training programs for healthcare professionals and patients on the optimum use and maintenance of auto-injectors. It provides a rationale for their continued development.

Drug delivery improvements to enable a flexible care setting for monoclonal antibody medications in oncology - Analogue-based decision framework

INTRODUCTION

The substantial acceleration in healthcare spending together with the expenditures to manage the COVID19 pandemic demand drug delivery solutions that enable a flexible care setting for high-dose monoclonal antibodies (mAbs) in oncology.

AREAS COVERED

This expert opinion introduces an analogue-based framework applied to guide decision-making for associated product improvements for mAb medications that are either already authorized or in late-stage clinical development. The four pillars of this framework comprise (1) the drug delivery profile of current and emerging treatments in the market, (2) the needs and preferences of people treated with mAbs, (3) existing healthcare infrastructures, and (4) country-dependent reimbursement and procurement models. The following product optimization examples for mAb-based treatments are evaluated based on original research and review articles in the field: subcutaneous formulations, an established drug delivery modality to reduce parenteral dosing complexity, fixed-dose combinations, an emerging concept to complement combination therapy, and (connected) on-body delivery systems, an identified future opportunity to support dosing outside of a controlled healthcare institutional environment.

EXPERT OPINION

Leveraging existing synergies and learnings from other disease areas is a measure to reduce associated development and commercialization costs and thus to provide sustainable product offerings already at the initial launch of a medication.

Enabling faster subcutaneous delivery of larger volume, high viscosity fluids

OBJECTIVES

Many current subcutaneous (SC) biologic therapies may require >1 mL volume or have increased viscosity, necessitating new delivery system approaches. This study evaluated 2-mL large-volume autoinjector (LVAI) delivery performance across varying solution viscosities and design inputs to assess the design space and identify configurations that produce practical injection times.

METHODS

Investigational LVAI delivery duration and volume, depot location, and tissue effects were examined in both air and in vivo models across various pre-filled syringe (PFS) cannula types (27 G Ultra-thin wall [UTW], 27 G special thin wall [STW], or 29 G thin-wall [TW]), drive spring forces (SF_LOW or SF_HIGH), and Newtonian solutions (2.3-50 centipoise [cP]).

RESULTS

Within each design configuration, increasing PFS internal diameters and spring forces reduced delivery times, while increasing viscosity increased times. The 27 G UTW PFS/SF_HIGH combination achieved shorter delivery times across all injection conditions, with 2 mL in vivo durations <15 seconds at ≤31 cP and routinely <20 seconds at 39 and 51 cP, with nominal and transitory tissue effects.

CONCLUSION

PFS cannula and spring force combinations can be tailored to achieve various injection durations across viscosities, while UTW PFS enables faster rates to potentially better accommodate human factors during LVAI injection, especially at high viscosity.

Safety evaluation of antibacterial and analgesic autoinjector devices for rapid administration during emergency situations: a crossover study in rabbits

Objective:

The objective of the present study was to evaluate the safety and tolerability of autoinjector devices (AIDs) in rabbits by intramuscular (i.m.) administration, using haematological and biochemical markers.

Introduction:

Emergency and mass casualty situations require immediate drug delivery for which AIDs are preferred. The tolerability of amikacin as antibacterial and buprenorphine as analgesic AID has been studied in rats by intraperitoneal administration. In the present study, it was evaluated in rabbits by i.m. administration.

Methods:

Water-filled glass cartridges (2.3–2.4 mL) were converted to amikacin (106 mg/mL) and buprenorphine (0.128 mg/mL) cartridges. Dual dose AID was used for i.m. administration (1.2 mL). The study was done as a crossover design on 12 rabbits. Initially, three rabbits each were given manually or AID, 57 mg/kg amikacin, and three rabbits each by manual or by AID, 0.07 mg/kg buprenorphine for 7 days. After 1 month, the injections were changed in the rabbits. In the place of manual injection, AID and in the place of amikacin, buprenorphine injection was given. This ensured that all rabbits received 14 injections, 7 manual and 7 AID consisting of 7 amikacin and 7 buprenorphine. 24 h before and 24 h after last drug administrations, blood was withdrawn from ear vein for haematological and biochemical estimations.

Results:

The rabbits were healthy, active and no sign of any injection-related changes were observed after administration of amikacin and buprenorphine by manually or by AID. The haematological and biochemical parameters showed similar changes in manual and AID administration of amikacin and buprenorphine.

Conclusion:

The present study of amikacin and buprenorphine by AID shows the safety of the device and is recommended for further experimentation. These AIDs are intended for self-administration during emergency and mass causality situation and are suitable for adults and children, as well as farm and pet animals.

The current paradigm for biologic initiation: A confirmatory quantitative analysis of self-injection training practices

BACKGROUND

Self-injected biologic therapies have gained significant prevalence across numerous therapeutic areas. A lack of specific guidance on best practices may lead to inadequate biologic initiation and training. We previously conducted a small-sample, qualitative analysis designed to identify gaps in self-injection training.

METHODS

A total of 277 HCPs performing routine biologic initiation and 264 patients currently self-injecting biologics completed this quantitative study remotely using an online survey. The primary objective was to validate previous qualitative findings and firmly characterize the current paradigm. As an exploratory objective, the study examined associations that may exist between training experiences and patient-reported outcomes.

RESULTS

Most patients (91.7%) reported receiving formal self-injection training, commonly conducted over one or two sessions. The mean overall training time reported was 37.8 and 30.4 minutes by patients and HCPs, respectively. Over one-third of patients reported lacking confidence that they could correctly self-inject during the first 6 months of treatment.

CONCLUSION

Current training practices may not be adequate to prepare patients to start their therapies. Considerable attention must be paid to providing patients with multiple opportunities for training sessions, training devices, and medical information for home access. Further studies should prospectively examine the impact of training techniques on patient-reported outcomes.

Home-based treatment of biologics for asthma: who, what, where, when and why

INTRODUCTION

The advent of biologic therapies for severe asthma has profoundly changed the management of this pathology. The introduction of home administration is therefore an important innovation to optimize the patients' management, even if there are many aspects that need to be clarified and pointed out.

AREAS COVERED

This review summarizes the path that led to the possibility of self-administration of biologics, and what the pandemic has changed in the management of these patients.

EXPERT OPINION

The growing understanding of asthma phenotypes and endotypes is enabling the careful selection of patients suitable for biologics. In this context, the availability of reliable and simple self-injection devices is important in implementing self-administration. The transition to self-injection is also possible thanks to the high safety profile of biologics. With attention, most patients may potentially be suitable for self-administration. The transition process from hospital to home administration can therefore be carried out correctly by clinicians with adequate expertise in the field of severe asthma and biologic therapies, with the support of other health professionals, pharmacists, and general practitioners. Home administration is probably the best way to guarantee high adherence and high-level satisfaction of patients, even in the long term.

Formative and Validation Human Factors studies of a new disposable autoinjector for subcutaneous delivery of chronic disease therapies

BACKGROUND

Use-related risks related to autoinjector devices have been previously identified. To minimize these problems, the identification of potential use errors is a critical task during device development.

METHODS

This article presents iterative human factor studies, which aim to assess user interaction with the tested push-on-skin BD Intevia™ 1 mL Disposable Autoinjector, across a wide range of indications, and a broad user population.

RESULTS

Through the different human factor studies, use errors were recorded when the participants completed the critical tasks, but their occurrence continuously decreased. First, the incidence of use errors was reduced when the participants read the IFU. In addition, the IFU updates and design change implemented contributed to improve the usability performance. During the validation study, some use errors were still observed, mainly during the first uses. Nevertheless, providing a training to the participants almost fully eliminated the remaining use errors.

CONCLUSION

Thus, these results demonstrated that this new autoinjector can be safely and efficiently used for its intended uses and under the expected use conditions by all tested user groups.

The current paradigm for biologic initiation: a mixed-methods exploration of practices, unmet needs, and innovation opportunities in self-injection training

BACKGROUND

Self-injection, particularly of biologics, has become a mainstay of chronic disease management. Despite labeling requirement for healthcare provider (HCP) training, current injection initiation experiences have been shown to be suboptimal. This study characterizes gaps in training and support during initiation and identifies rationales to inform solutions.

METHODS

We enrolled HCPs (n = 18) performing routine biologic initiation and patients (n = 24) currently self-injecting biologics. Participants completed activities through an online, remote ethnography tool. We conducted two focus groups with biologic-naïve patients (n = 5). Data was analyzed using thematic frameworks, Q methodology, and quantitative assessments.

RESULTS

Our results suggest considerable gaps exist. Analysis revealed five common themes that could explain these gaps: 1) minimal biologic-specific professional instruction is provided to HCPs; 2) nuanced injection use-steps are not universally understood; 3) no one stakeholder currently 'owns' training; 4) support offered by HCPs and manufacturers is perceived as biased; and 5) emotional burden is not accounted for.

CONCLUSIONS

Our study suggests optimizing several elements to facilitate successful initiations, including structured sessions, improved HCP injection device knowledge, demo-device practice, and focus on both emotional and mechanical aspects. Aligning these factors has potential to increase patient confidence, reduce burden on HCPs, and improve probability of success on therapy.

Risk of dosing errors in ART treatment: user experience of single- vs multi-use follitropin alfa pens

Background: This user experience study evaluated the suitability of single-use versus multi-dose follitropin alfa pen injectors for self-administration by women undergoing fertility treatment.Methods: Twenty-four fertility patients and 19 specialist nurses were recruited in four European countries to assess their use of Bemfola (a single-use pen), Gonal-f®, and Ovaleap® (multi-use pens). Participants completed usability tests in which their performance in assembling and administering doses of each pen was assessed against defined critical steps for ensuring safe and correct administration.Results: Critical error rates among nurses were 4%, 40%, and 49% for Bemfola®, Ovaleap®, and Gonal-f®, respectively; and among patients were 7%, 16%, and 38%. The most frequently reported critical errors occurred with the multi-use pens and were incorrect/lack of priming and failure to check the dose window prior to setting a new dose. The need to 'top up' doses from a new pen or cartridge when a pen contained insufficient dose also caused errors. The single-use pens did not cause these errors. Overall, 63% of nurses and 67% of patients had most confidence in Bemfola® for correct dosing and self-administration.Conclusions: Single-use pens require fewer preparation and administration steps than multi-use pens and are associated with fewer critical handling errors.

Remote videolink observation of model home sampling and home testing devices to simplify usability studies for point-of-care diagnostics

Both home sample collection and home testing using rapid point-of-care diagnostic devices can offer benefits over attending a clinic/hospital to be tested by a healthcare professional. Usability is critical to ensure that in-home sampling or testing by untrained users does not compromise analytical performance. Usability studies can be laborious and rely on participants attending a research location or a researcher visiting homes; neither has been appropriate during COVID-19 outbreak control restrictions. We therefore developed a remote research usability methodology using videolink observation of home users. This avoids infection risks from home visits and ensures the participant follows the test protocol in their home environment. In this feasibility study, volunteers were provided with models of home blood testing and home blood sampling kits including a model lancet, sampling devices for dried blood spot collection, and model lateral flow device. After refining the study protocol through an initial pilot (n = 7), we compared instructions provided either as written instructions (n = 5), vs addition of video instructions (n = 5), vs written and video instructions plus videolink supervision by the researcher (n = 5). All users were observed via video call to define which test elements could be assessed remotely. All 22 participants in the study accessed the video call and configured their videolink allowing the researcher to clearly observe all testing tasks. The video call allowed the researcher to assess distinct errors during use including quantitative (volume of blood) and qualitative (inaccurate interpretation of results) errors many of which could compromise test accuracy. All participants completed the tasks and returned images of their completed tests (22/22) and most returned completed questionnaires (20/22). We suggest this remote observation via videolink methodology is a simple, rapid and powerful methodology to assess and optimise usability of point-of-care testing methods in the home setting.

Co-Creation of a Lanreotide Autogel/Depot Syringe for the Treatment of Acromegaly and Neuroendocrine Tumours Through Collaborative Human Factor Studies

INTRODUCTION

Although the previous lanreotide autogel/depot syringe had been well received, feedback indicated that improvements could be made to make it more user-friendly. Additionally, the view that patients should have greater involvement in the research and development process is echoed by the International Neuroendocrine Cancer Alliance. A series of studies aimed to develop and validate a new syringe that works better for patients, caregivers and healthcare professionals (HCPs) by involving these groups at key stages in the development and testing process.

METHODS

The multicentre, international, human factor studies, consisted of four formative studies and one validation study. The formative studies collected patient, caregiver and HCP feedback on the lanreotide autogel/depot syringe on the market at the time, and on newly designed prototypes. The validation study was conducted to evaluate the final syringe to confirm that it can be used effectively and safely in the intended environment, by the intended user, for the intended purpose.

RESULTS

Overall, 213 individuals participated in the studies; 145 contributed to the formative studies and 68 to the validation study. The validated new-generation syringe included several important updates compared with the lanreotide autogel/depot syringe currently on the market, including the flanges, which are now larger and have a better grip; the overcap, which is white, ridged, opaque and bigger; the plunger supports and the thermoformed tray. No participant hurt themselves or others during the validation study (although several misuses were reported), and all participants succeeded in delivering a complete dose and activating the safety system.

CONCLUSION

With collaboration, a new syringe was developed to meet the needs of patients, caregivers and HCPs, whilst ensuring lanreotide was delivered effectively and safely. These studies highlight the importance of involving patients, caregivers and HCPs in clinical evaluation studies to develop medical products that address their concerns and meet their needs.

FUNDING

Ipsen. Plain language summary available for this article.