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

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.

Geriatric drug delivery - barriers, current technologies and the road ahead

The geriatric population encompasses the largest part of the health care system worldwide. Chronic medical conditions are highly prevalent in the elderly, consequently, due to their complex health needs, there is a significant rate of multi-drug therapy. Despite the high numbers of medications prescribed, geriatric patients face several barriers when it comes to successful drug delivery including alterations in cognitive and physical function. The current review highlights the impact of chronic diseases on the ageing population along with how changes in drug pharmacokinetics could impact drug efficacy and safety. Also discussed are applications of administration routes in the geriatric population and complications that could arise. A focus is placed on the traditional and upcoming drug delivery advancements being employed in seniors with a focus addressing obstacles faced by this patient category. Nanomedicines, three-dimensional printing, long-acting formulations, transdermal systems, orally disintegrating tablets, and shape/taste modification technologies are discussed. Several barriers to drug delivery in the elderly have been identified in literature and directions for future studies should focus on addressing these gaps for geriatric drug formulation development including personalised medicine, insights into novel drug delivery systems like nanomedicines, methods for decreasing pill burden and shape/size modifications.ARTICLE HIGHLIGHTSTypically, senior citizens take more medications than any other patient population, yet most drug delivery technologies are not tailored to address the specific cognitive and physical barriers that these individuals encounter.The safety of drug delivery systems in the elderly patients should be prioritised with considerations on changes in pharmacokinetics with age, use of non-toxic excipients, and selecting drugs with minimal off-target side effects.Several commercialised and upcoming drug delivery technologies have begun to address the current limitations that the ageing population faces.Future research should focus on applying novel strategies like 3D printing, personalised medicine, and long-acting formulations to improve drug delivery to elderly patients.

Formative and validation human factors studies of a new disposable prefilled injection device for subcutaneous delivery of acthar gel (repository corticotropin injection)

BACKGROUND

The administration of repository corticotropin injection (Acthar Gel) via a single-dose prefilled injector (SelfJect) is intended to provide a simple, ergonomic alternative to traditional injection. Iterative human factors (HF) studies were conducted to identify potential use deviations and ensure appropriate device use.

RESEARCH DESIGN AND METHODS

This article presents seven formative studies, a validation study (with prior pilot validation studies), and a supplemental validation study with participants including lay users, patients, caregivers, and healthcare providers. Participant interactions with SelfJect and the user interface were assessed. Use deviations, user preferences, and participants' ability to successfully complete tasks were evaluated to generate modifications to the device and user interface.

RESULTS

In the validation study, 91% of participants successfully administered their first injection. Use errors were rare with simulated-use (6.9%) and knowledge-based (1.6%) testing. Use deviations were commonly attributed to experimental artifact or information oversight, and device warming had the most use errors (49% of participants), even with extensive testing and adjustments to the user interface.

CONCLUSIONS

SelfJect was able to be used in a safe and effective manner by the intended users. Iterative HF studies informed the mitigation of use-related risks to reduce the occurrence of use deviations during simulated use.

Postmarketing Reports of Incomplete Dosing-Related Complications with Self-Injected PCSK9 Inhibitors: A Descriptive Study and Disproportionality Analysis

BACKGROUND

Evolocumab and alirocumab are self-injected proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors indicated for low-density lipoprotein cholesterol reduction. Complications in the use or functionality of self-injection devices may precipitate incomplete dosing.

OBJECTIVE

This study sought to characterize postmarketing dosing failure reports involving self-injected PCSK9 inhibitors.

METHODS

US Food and Drug Administration Adverse Event Reporting System (FAERS) [2016-second quarter of 2023] data were utilized for a disproportionality analysis. Eight self-injected comparator medications served as referents. Medical Dictionary for Regulatory Activities preferred terms indicating explicit or probable failure to administer a complete dose classified cases. Proportional reporting ratios (PRRs) > 2.0 and lower 95% confidence intervals (CIs) > 1.0 indicated disproportionality signals. US FDA Manufacturer and User Facility Device Experience (MAUDE) [2013-2023] data underwent a narrative review.

RESULTS

During the study period, 194,781 (evolocumab, n = 152,831; alirocumab, n = 41,950) drug-event pairs and 43,725 (evolocumab, n = 38,489; alirocumab, n = 5236) cases reported to FAERS identified PCSK9 inhibitors. MAUDE contained six evolocumab reports, half describing dose omission, and no alirocumab reports. A potential dosing failure signal was detected for evolocumab (PRR 2.01; 95% CI 1.98-2.03), but not alirocumab (PRR 0.99; 95% CI 0.97-1.02), relative to pooled comparator reports. Across three case term subcategories, incomplete dosing disproportionality signals were further identified for evolocumab patient usage complication terms (PRR 3.44; 95% CI 3.38-3.50) and alirocumab device malfunction terms (PRR 2.09; 95% CI 1.98-2.22).

CONCLUSIONS

Proprotein convertase subtilisin kexin type 9 inhibitor incomplete dosing-related complications are frequently reported in the postmarketing setting. Systematic efforts to understand the incidence and mechanisms of dosing failure and associated patient burdens are needed.

Framework for creating a qualified medical device development tool of autoinjectors

Objectives

Autoinjectors are pivotal for precise self-administration of medications across a wide range of medical conditions. Nevertheless, the absence of a dedicated Medical Device Development Tool (MDDT) for autoinjectors represents a gap that may result in variations in the quality and regulatory compliance of autoinjectors as components of combination products. This research aim is to utilize the recently introduced Primary Functions outlined in ISO 11608-1:2022 with the title "Needle-based injection systems for medical use. Requirements and test methods. Part 1: Needle-based injection systems" to create a comprehensive MDDT framework tailored specifically for autoinjectors.

Methods

To support the creation of the framework, the analysis of the FDA MDDTs that were already approved, FDA's design controls regulations, FDA's guidance related to autoinjectors, and the Primary functions outlined in ISO 11608-1:2022 were utilized.

Results

The research identifies the Primary Functions in autoinjector to be Holding Force, Cap Removal Force, Activation Force, Extended Needle Length, Injection Time, Dose Accuracy and Needle Guard Lockout. Leveraging these Primary Functions and the FDA's MDDT approach, the research aims to bridge the gap by proposing a structured framework for the development of a specific MDDT tailored to autoinjectors.

Conclusion

This study presents a MDDT framework tailored to the development of autoinjectors for drug delivery. This framework provides a structured methodology to support predictability and effectiveness of the autoinjector development and support regulatory review process, thereby expediting FDA approval for autoinjectors as part of combination product.