Hold the device against the skin: the impact of injection duration on user’s force for handheld autoinjectors

An industry perspective on hyaluronidase co-formulated biopharmaceutics

To deliver biopharmaceutics, subcutaneous (SC) route surpasses intravenous (IV) route unequivocally in time and cost savings, but it has been limited by the injection volume of no greater than 2 mL for a long time. Recently, the adoption of hyaluronidase has become a plausible method to realize high-dose high-volume biopharmaceutical products for SC injection. Among the hyaluronidase family, the recombinant human PH20 appears to be the most reliable candidate with excellent efficacy and safety for co-formulation development. As of 2024, a total of eight hyaluronidase co-formulated biological products have been approved by regulatory authorities. This review article systematically summarized the commercial hyaluronidase co-formulated biopharmaceutics and highlighted the critical aspects of the development of future products regarding selection of hyaluronidase, formulation and process development, non-clinical evaluation, and clinical investigation. Of note, considering the uniqueness of each therapeutic agent, early and effective communication with regulatory authorities is of vital importance to successful development. Discussions were further Expanded to cover the combination of hyaluronidase co-formulations with large-volume handheld autoinjectors. The ultimate goal of this review is to provide a practical and comprehensive reference that will substantially contribute to the development of hyaluronidase co-formulated biopharmaceuticals, thereby advancing the field and benefiting patients worldwide.

Autoinjector optimization through cavitation response and severity minimization

Abrupt acceleration of the syringe of an autoinjector (AI) upon rod-plunger impact may induce undesired severe cavitation events and impose extraneous stresses upon the device, leading to device failure. Cavitation results from a rapid and significant pressure drop in a liquid, leading to the formation and growth of small vapor-filled cavities. Upon collapse, these cavities generate an intense shock wave that may lead to protein aggregation and device container damage and shatter. Since the maximum acceleration of the syringe depends upon the operating conditions of the AI, the severity of cavitation will likewise depend on the operating conditions of the AI. Likewise, injection time and ensuring proper needle displacement before drug release also depend on operating conditions, making optimization of the autoinjector a multiobjective optimization problem. Therefore, in this study, optimization of an autoinjector to limit cavitation severity is pursued via an experimentally validated computational model for cavitation in spring-driven autoinjectors. Our goal is to locate AI design configurations that balance maximizing device performance and patient comfort and minimizing the risks of device damage and severe cavitation upon actuation. Relevant parameters of interest are the drive spring force, air gap height, solution viscosity, friction between the rod and spring, frictional force on the plunger, rates of change of frictional force on the plunger, elasticity of plunger, viscosity of the plunger, and initial displacement between the plunger and the driving rod. The kinematics of the syringe barrel, needle displacement (travel distance) at the start of drug delivery, and injection time are gathered using an experimentally validated autoinjector kinematics model. At the same time, cavitation bubble dynamics are resolved using an experimentally validated cavitation model that takes the temporal displacement of the syringe and temporal air gap pressure as inputs. We use our experimentally validated models to explore the parameter space and understand the driving factors of our desired outcomes. Subsequently, we pose the design problem as a multi-objective optimization problem and develop a deep neural network surrogate model supplemented with iterative learning to speed up optimization. A variance-based sensitivity analysis was performed to determine the sensitivity and influence of design parameters on the outcomes, and the main contributors to the outcomes of interest were isolated. Using a multi-objective optimization framework, we located 300 + successful candidates and evaluated them through uncertainty analysis to identify three promising candidates that meet all criteria for drug viscosities of interest. Finally, we show that this methodology can be used to conduct hypothesis testing, leading to novel design configurations.

Jet injection through microneedles for large volume subcutaneous delivery

Subcutaneous (SC) drug delivery offers several advantages over intravenous (IV) delivery including: self-administration, improved patient experience, and reduced treatment costs. Unfortunately, each SC delivery is currently limited to ∼ 2.25 mL with IV administration required when the delivery volume exceeds this value. In this work, we explore a new technique for large volume subcutaneous drug delivery that uses microneedles to break through the epidermis then forms the liquid drug into many small jets that penetrate past the ends of the microneedles and into the subcutaneous (or muscle) tissue. By performing multiple simultaneous injections, this delivery approach avoids the volume limitations of SC delivery, and thus may be able to greatly increase the volume we can deliver to this space. Here, we present a novel multi-jet prototype that forms seven simultaneous jets through 30G needles that have been shortened to have an exposed length of just ∼ 1mm. The jet speed, shape, and volume of jets formed through these microneedles are measured to assess the consistency of jet production through the microneedles. We then perform jet injections of volumes up to 3.9 mL into ex vivo porcine tissue. The results demonstrate the successful delivery (>95 %) of 3.9 mL in just 0.3 s using jet injection performed through microneedles. This volume is almost double the maximum volume of current autoinjectors and the perceived limit for subcutaneous injection (2.25 mL). We also find that jet speeds of 70 m/s and below do not achieve complete delivery of 3.9 mL with our prototype system, and that the addition of microneedles leads to more consistent large volume delivery than equivalent needle-free injections. These results demonstrate the promise of multi-jet injection through microneedles to accommodate volumes much greater than current autoinjectors, and thus potentially allow patient self-administration in many more delivery applications.

Clinical assessment of the potential use of a novel single-dose prefilled injection device for the administration of Acthar Gel in children: a narrative review

Acthar® Gel (repository corticotropin injection; Mallinckrodt Pharmaceuticals, NJ, USA) is indicated for the treatment of myriad inflammatory disorders and is currently administered manually via a vial and syringe. The administration of Acthar via a single-dose prefilled injector (SelfJect™) is intended to simplify its subcutaneous (SC) delivery. The purpose of this review was to determine whether SelfJect is suitable for use in pediatric patients through a literature assessment of various factors, including skin depth, needle length and gauge, dosage, force required for injection, and potential harms. Infants and young children, who commonly have skin-to-muscle distances less than the minimum depth of SelfJect administration, may have risk of unintentional intramuscular (IM) injection; however, an inadvertent IM injection poses no additional risk to children because of the bioequivalence between SC and IM administration of Acthar. The needle gauge of SelfJect is acceptable for pediatric patients and aligns with the Centers for Disease Control and Prevention recommendations for SC injections. The dosage delivered by SelfJect is only appropriate for children over 2 years of age. Although adolescents would likely be able to achieve the minimum force required to remove the protective cap and deliver a full dose of Acthar with SelfJect, an adult (18 years of age and older) should administer SelfJect to pediatric patients. In addition to the commonly reported postmarketing adverse events (AEs) from Acthar administration (e.g., asthenic conditions, fluid retention, insomnia, headache and increased blood glucose), injection site-related AEs common to injection devices may occur with SelfJect use. The risk of needlestick injury from SelfJect is mitigated by a needle guard. In summary, this review of injection device considerations demonstrates that SelfJect is appropriate for use in the pediatric population.

Glass Silicone Oil Free Pre-filled Syringe as Primary Container in Autoinjector

OBJECTIVE

Pre-filled syringes (PFSs) have become popular as a convenient and cost-effective container closure system for delivering biotherapeutics. However, standard siliconized PFSs may compromise the stability of therapeutic proteins due to their exposure to the silicone oil-water interface. To address this concern, silicone oil-free (SOF) glass syringes coupled with silicone-oil free plunger stoppers have been developed. This study aims to compare the impact of silicone oil-free (SOF) and siliconized syringes as primary container on protein stability and device functionality of the combination products.

METHODS

The stability of proteins with different modalities was assessed in SOF and siliconized 1 mL glass syringes for up to 6 months at 5℃, 25℃, and 40℃ with levels of subvisible particles and soluble aggregate determined by micro-flow imaging (MFI) and ultra performance size-exclusion chromatography (UP-SEC). The functionality of SOF glass syringes, including break loose force, extrusion force and delivery time in autoinjectors, was evaluated at different time points during the stability study. Additionally, SOF glass syringes were filled with viscosity surrogate ranging from 1 to 90 cP to understand the impact of solution viscosity on break loose force, extrusion force, and autoinjector delivery time.

RESULTS

SOF demonstrates compatibility with proteins and exhibited significantly low particle counts compared to siliconized PFS. SOF syringes show significantly higher break-loose and extrusion forces. However, unlike siliconized syringes where silicone oil migration increases extrusion force, no significant change in functionality was observed in SOF glass syringe during stability testing. Overall, SOF glass syringes showed great potential as an alternative package for biologics with comparable performance on functionality as siliconized PFS.

CONCLUSIONS

The combination of SOF glass and its PTFE coated stopper presents a new primary container closure system with both adequate protein stability and desired functionality features.

Investigation into the Acceptability of Moderate-to-Large Volume Subcutaneous Injections in Healthy Volunteers: Results from a Single-Center Randomized Controlled Study

Purpose

Therapeutic proteins are often delivered by subcutaneous (SC) autoinjector to enable self-administration. Autoinjectors typically deliver up to 1 mL injected volumes per dose. Delivery of larger volumes may be limited by injection site discomfort, including pain, swelling, and redness. Delivery at a slower rate may mitigate this discomfort. This single-center, randomized, crossover study evaluated the acceptability and tolerability of varying volumes and delivery rates of SC saline in healthy volunteers.

Patients and Methods

Eligible participants were adults (18-65 years) with a body mass index of 18.5-32.0 kg/m2. Participants (N = 24) were randomized to multiple sequences of infusions over five visits, with infusions ranging from 1 to 5 mL at rates of 1.50-6.00 mL/minute (min) and including a 1 mL SC infusion in 10 seconds (s) at a rate of 6.00 mL/min. The primary objective was to identify acceptable volume and delivery rates of SC saline, as assessed by visual analogue scale (VAS) pain scores, a tolerability and acceptability questionnaire, and infusion leakage.

Results

Infusions that met the acceptability criteria were 1 mL in 10s, 4 mL in 58s, and 3 mL in 2 mins. Higher delivery volumes and rates were associated with higher VAS pain scores but remained within the VAS acceptability criteria.

Conclusion

These findings may support the development of larger-volume injectors for self-administration of future medicines.

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.

Modeling drug transport and absorption in subcutaneous injection of monoclonal antibodies: Impact of tissue deformation, devices, and physiology

The pharmaceutical industry has experienced a remarkable increase in the use of subcutaneous injection of monoclonal antibodies (mAbs), attributed mainly to its advantages in reducing healthcare-related costs and enhancing patient compliance. Despite this growth, there is a limited understanding of how tissue mechanics, physiological parameters, and different injection devices and techniques influence the transport and absorption of the drug. In this work, we propose a high-fidelity computational model to study drug transport and absorption during and after subcutaneous injection of mAbs. Our numerical model includes large-deformation mechanics, fluid flow, drug transport, and blood and lymphatic uptake. Through this computational framework, we analyze the tissue material responses, plume dynamics, and drug absorption. We analyze different devices, injection techniques, and physiological parameters such as BMI, flow rate, and injection depth. Finally, we compare our numerical results against the experimental data from the literature.

In vitro modelling of intramuscular injection site events

INTRODUCTION

Intramuscular (IM) injections deliver a plethora of drugs. The majority of IM-related literature details dissolution and/or pharmacokinetic (PK) studies, using methods with limited assessments of post-injection events that can impact drug fate, and absorption parameters. Food and Drug Association guidelines no longer require preclinical in vivo modeling in the U.S.A. Preclinical animal models fail to correlate with clinical outcomes, highlighting the need to study, and understand, IM drug fate in vitro using bespoke models emulating human IM sites. Post-IM injection events, i.e. underlying processes that influence PK outcomes, remain unacknowledged, complicating the application of in vitro methods in preclinical drug development. Understanding such events could guide approaches to predict and modulate IM drug fate in humans.

AREAS COVERED

This article reviews challenges in biorelevant IM site modeling (i.e. modeling drug fate outcomes), the value of technologies available for developing IM injectables, methods for studying drug fate, and technologies for training in performing IM administrations. PubMed, Web-of-Science, and Lens databases provided papers published between 2014 and 2024.

EXPERT OPINION

IM drug research is expanding what injectable therapeutics can achieve. However, post-injection events that influence PK outcomes remain poorly understood. Until addressed, advances in IM drug development will not realize their full potential.

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.

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.

The Needle Shield Size and Applied Force of Subcutaneous Autoinjectors Significantly Influence the Injection Depth

BACKGROUND

This study examines how shield-triggered autoinjectors (AIs), for subcutaneous drug delivery, affect injection depth. It focuses on shield size and applied force, parameters that could potentially lead to inadvertent intramuscular (IM) injections due to tissue compression.

METHOD

A blinded ex-vivo study was performed to assess the impact of shield size and applied force on injection depth. Shields of 15, 20, and 30 mm diameters and forces from 2 to 10 N were investigated. The study involved 55 injections in three Landrace, Yorkshire, and Duroc (LYD) pigs, with injection depths measured with computed tomography (CT). An in-vivo study, involving 20 injections in three LYD pigs, controlled the findings, using fluoroscopy (FS) videos for depth measurement.

RESULTS

The CT study revealed that smaller shield sizes significantly increased injection depth. With a 15 mm diameter shield, 10 N applied force, and 5 mm needle protrusion, the injection depth exceeded the needle length by over 3 mm. Injection depth increased with higher applied forces until a plateau was reached around 8 N. Both applied force and size were significant factors for injection depth (analysis of variance [ANOVA], P < .05) in the CT study. The FS study confirmed the ex-vivo findings in an in-vivo setting.

CONCLUSIONS

The study demonstrates that shield size has a greater impact on injection depth than the applied force. While conducted in porcine tissue, the study provides useful insights into the relative effects of shield size and applied force. Further investigations in humans are needed to confirm the predicted injection depths for AIs.

Large volume subcutaneous delivery using multi-orifice jet injection

Needle-free jet injection is an alternative drug delivery technique that uses the liquid drug itself to penetrate through the skin. This technology is not only a promising alternative to hypodermic needles but also has the potential to replace intravenous delivery with rapid, needle-free subcutaneous delivery for large-volume treatments. In this work we propose a parallelised, 'multi-orifice' approach to overcome the volume constraints of subcutaneous tissue. We present a prototype multi-orifice nozzle with up to seven orifices and use this nozzle to perform injections into samples of ex vivo porcine tissue. These injections demonstrated the rapid (<0.15 s) delivery of up to 2 mL into the tissue using both three and seven orifices. Delivery success (measured as the percentage of fluid deposited in the tissue relative to the total volume that left the device) was very similar when using three versus seven injection orifices. A computational fluid dynamic model of multi-orifice jet injection is also presented. This model predicts that jet production is largely unaffected as the spacing between orifices is changed from 3 mm to 48 mm. This finding is supported by measurements of the speed, volume, and shape of the jets produced by the prototype nozzle that showed very similar jets were produced through all seven orifices. These findings demonstrate the feasibility of multi-orifice jet injection for needle-free delivery of large volumes. This promising technique has the potential to improve patient experience and reduce healthcare costs in large volume parenteral delivery applications.

Computational modeling of the effect of skin pinch and stretch on subcutaneous injection of monoclonal antibodies using autoinjector devices

Subcutaneous injection of monoclonal antibodies (mAbs) has experienced unprecedented growth in the pharmaceutical industry due to its benefits in patient compliance and cost-effectiveness. However, the impact of different injection techniques and autoinjector devices on the drug's transport and uptake is poorly understood. Here, we develop a biphasic large-deformation chemomechanical model that accounts for the components of the extracellular matrix that govern solid deformation and fluid flow within the subcutaneous tissue: interstitial fluid, collagen fibers and negatively charged proteoglycan aggregates. We use this model to build a high-fidelity representation of a virtual patient performing a subcutaneous injection of mAbs. We analyze the impact of the pinch and stretch methods on the injection dynamics and the use of different handheld autoinjector devices. The results suggest that autoinjector base plates with a larger device-skin contact area cause significantly lower tissue mechanical stress, fluid pressure and fluid velocity during the injection process. Our simulations indicate that the stretch technique presents a higher risk of intramuscular injection for autoinjectors with a relatively long needle insertion depth.

Blinding Is Seeing: A Single-Centre Study Into the Viability of Auto-Injectors for Blinded-Drug Administration in Randomised Controlled Trials

Objective The aim of the study was to assess the viability of auto-injector systems (A-INJ) for preserving investigator blinding in randomized controlled trials (RCT). Background Blinding refers to the concealment of group allocation from one or more individuals involved in a clinical research study. In the dosing of subcutaneous (SC) and intramuscular (IM) investigational medicinal products (IMP), specific challenges arise in maintaining investigator blinding. These challenges primarily involve the active injectate's viscosity and visual appearance (colour/translucency) in comparison to the placebo. Existing methods to control these issues are not perfect. Common approaches include using unblinded investigators or applying films or additives to make the active and placebo injectates appear similar. Method A single-centre experimental and descriptive study was carried out to compare the use of an A-INJ (Owen Mumford, Autoject 2) with the use of a conventional syringe (CS) in delivering a 1 ml dose of both placebo and reference IMP. The percentage delivery of the injectate was compared between the A-INJ IMP and placebo groups. Additionally, eight trained research physicians serving as investigators recorded their assessments of safety and effectiveness after performing serial injections with the A-INJ into a human-tissue analogue. Results Overall, a mean of 95.38% of 1ml placebo injectate was released from the A-INJ, compared to 96.00% from the CS. A total of 94.715% of 1 ml IMP injectate was released from the A-INJ, as opposed to 94.74% from the CS. Independent t-test analyses showed no statistical significance between the experimental arms. The mean administration time was 8.5 seconds. Investigators were unable to differentiate between the two solutions when using the A-INJ. There were no recorded concerns about investigators becoming unblinded, which stands in contrast to concerns associated with using the CS. Conclusion In assessing the viability of A-INJ use in RCTs, we noted a marked improvement when blinding was used. A-INJ systems effectively administer both placebo and active injectates, thereby maintaining the benefit of blinding without the need to alter the placebo through the addition of colourants or viscosity additives. While audio cues from the A-INJ and the time required to administer the injectate pose challenges, solutions are suggested. Although our findings are preliminary, they add to the existing literature on the advantages of A-INJs for administering injectable compounds and offer new perspectives on their utility in RCTs.

Modeling large-volume subcutaneous injection of monoclonal antibodies with anisotropic porohyperelastic models and data-driven tissue layer geometries

Subcutaneous injection of therapeutic monoclonal antibodies (mAbs) has become one of the fastest-growing fields in the pharmaceutical industry. The transport and mechanical processes behind large volume injections are poorly understood. Here, we leverage a large-deformation poroelastic model to study high-dose, high-speed subcutaneous injection. We account for the anisotropy of subcutaneous tissue using of a fibril-reinforced porohyperelastic model. We also incorporate the multi-layer structure of the skin tissue, generating data-driven geometrical models of the tissue layers using histological data. We analyze the impact of handheld autoinjectors on the injection dynamics for different patient forces. Our simulations show the importance of considering the large deformation approach to model large injection volumes. This work opens opportunities to better understand the mechanics and transport processes that occur in large-volume subcutaneous injections of mAbs.

Understanding patient preferences for handheld autoinjectors versus wearable large-volume injectors

OBJECTIVE

While interest in the use of wearable large-volume injectors for subcutaneous drug delivery is increasing, it remains unclear whether and under what conditions these emerging dosing options are preferred over more frequent but shorter administration of smaller doses using handheld autoinjectors. Therefore, the objective of this study was to examine the characteristics of patients diagnosed with cancer, diabetes, inflammatory and cardiovascular diseases, and treatment attributes that determine device preferences.

METHODS

Based on a cross-sectional online choice experiment, 191 participants expressed their preferences without being physically exposed to the devices or performing injections. Logistic hierarchical regression models were used to assess which patient characteristics, and how changes in treatment attributes, drive device preferences.

RESULTS

Participant quality of life reduced the likelihood of preferring wearable large-volume injectors to handheld autoinjectors. Moreover, reducing injection frequency from biweekly to monthly to quarterly injections, and shortening injection duration from 33 to 8 min, significantly increased the likelihood of patients preferring large-volume injectors to autoinjectors (p < 0.001).

CONCLUSION

The study revealed patient quality of life as predictor of device preference and identified critical inflection points in injection duration and injection frequency, at which patient preferences shift from handheld autoinjectors to wearable large-volume injectors.

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.

Design and Analysis: Servo-Tube-Powered Liquid Jet Injector for Drug Delivery Applications

The current state of commercially available needle-free liquid jet injectors for drug delivery offers no way of controlling the output pressure of the device in real time, as the driving mechanism for these injectors provides a fixed delivery pressure profile. In order to improve the delivery efficiency as well as the precision of the targeted tissue depth, it is necessary to develop a power source that can accurately control the plunger velocity. The duration of a liquid jet injection can vary from 10 to 100 ms, and it generate acceleration greater than 2 g (where g is the gravity); thus, a platform for real-time control must exhibit a response time greater than 1 kHz and good accuracy. Improving the pioneering work by Taberner and others whereby a Lorentz force actuator based upon a voice coil is designed, this study presents a prototype injector system with greater controllability based on the use of a fully closed-loop control system and a classical three-phase linear motor consisting of three fixed coils and multiple permanent magnets. Apart from being capable of generating jets with a required stagnation pressure of 15–16 MPa for skin penetration and liquid injection, as well as reproducing typical injection dynamics using commercially available injectors, the novelty of this proposed platform is that it is proven to be capable of shaping the real-time jet injection pressure profile, including pulsed injection, so that it can later be tailored for more efficient drug delivery.

Advances in subcutaneous injections: PRECISE II: a study of safety and subject preference for an innovative needle-free injection system

Needle-free injection is a desirable goal for many reasons, including reducing pain, anxiety, and eliminating safety risks associated with needle-stick injuries. However, development of a safe, reliable needle-free device optimized for at-home use has been met with many challenges. Portal Instruments Inc. has been developing needle-free medication delivery using a well-designed hand-held device, PRIME, that is safe, intuitive to use, and utilizes advanced electronic control of a focused, high velocity, pressurized liquid injection stream. The PRECISE II human study demonstrated that the PRIME needle-free injection system was safe, well tolerated, and strongly preferred by participants for self-injections over a standard needle and syringe. In addition, the study was able to be completed early for superiority following the success of the pre-defined interim analysis.

Formative Study on the Wearability and Usability of a Large-Volume Patch Injector

Background

The subcutaneous self-administration of biologics using a single large-volume bolus dose requires novel large-volume patch injectors. However, the usability and wearability of such on-body devices has rarely been investigated thus far. Therefore, this formative simulated use experiment studies the overall handling and acceptability in terms of the size and weight of a novel 10 mL large-volume patch injector device platform.

Methods

Twenty-three participants, including patients and healthcare professionals, simulated two injections with the large-volume patch injector, each lasting 17 min. During the injections, the patient participants performed predefined movements and activities with the on-body devices. Perceived usability and wearability were assessed through observation by the moderator and participant-reported feedback using five-point Likert scales and open-ended interviews.

Results

All participants successfully completed the simulated injections. Only non-serious usability issues were identified. Users rated the device acceptability in terms of wearability and usability with high ratings.

Conclusion

The results suggest the safe and effective usage of a novel prefilled large-volume patch injector that enables the subcutaneous delivery of a single bolus dose of up to 10 mL with an injection duration of 15 min. The participants of the simulated use study successfully used the device regardless of the disease state, age, or body size and habitus.

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.

A review of Formulations of Commercially Available Antibodies

This review identified 126 commercially available antibodies approved globally between 1986 and February 2021 including 10 antibody drug conjugates, 16 biosimilars, and 3 antibody fragments. Prior to 2014 there were ≤ 5 approved each year, but after 2014 there have been ≥ 7 approved each year with the years 2017, 2019 and 2020 having the most at 17 each. A total of 136 products were identified of which 36 are lyophilized powders and 100 are solutions. The routes of administration are mainly subcutaneous or intravenous infusion with three intravenous bolus, two intravitreal, and one intramuscular. The subcutaneous products are ready-to-use solutions or reconstituted lyophilized powders that do not require dilution while most intravenous products are concentrates that require dilution into saline or another intravenous fluid prior to infusion. Most are packaged in single-dose units and the exception of multi-use is Herceptin® and its biosimilars. The package configurations are vials, prefilled autoinjectors, or prefilled syringes. A typical antibody formulation contains an antibody, an excipient to adjust tonicity or osmolality for solutions or a lyoprotectant for lyophilized powders, a buffer, and a surfactant. The ionic tonicity-adjusting excipient is mainly sodium chloride and the non-ionic osmolality-adjusting excipients include sucrose, trehalose, mannitol, maltose, and sorbitol. The lyoprotectants are trehalose and sucrose. The pH range is 4.8-8.0 and the buffers or pH-modifying agents include histidine, citrate, succinate, acetate, phosphate, glutamate, adipic acid, aspartic acid, lactic acid, tromethamine, and 2-(N-morpholino)-ethanesulfonic acid. The surfactants include mostly polysorbate 20 or polysorbate 80, with four containing poloxamer 188, and one that does not contain a surfactant but contains PEG 3350. One product does not contain a buffer, and 12 do not contain a surfactant. The viscosity-lowering excipients are sodium chloride and the amino acids arginine, glycine, proline, and lysine. Arginine may also function to adjust ionic strength and minimize aggregation. Human serum albumin is used in 2 products for intravenous infusion. Other excipients include methionine as an anti-oxidant, and EDTA or DTPA as chelating agents. The maximum volume of subcutaneous injection is 15 mL administered over 3-5 minutes, but the typically volume is 0.5-2 mL. Five fixed-dose combinations have recently been approved and four contain hyaluronidase to assist the large volume subcutaneous injection of up to 15 mL, while one is a fixed-dose combination for intravenous with three antibodies. Prefilled autoinjectors and syringes are becoming more common and many come affixed with a needle of 27-gauge or 29-gauge, while a few have a 26-gauge or a 30-gauge needle. Recent advancements include hyaluronidase to assist the large subcutaneous injection volume of 5-15 mL, fixed-dose combinations, buffer-free formulation, and smaller subcutaneous injection volume (0.1 mL).

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

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.

Subcutaneous Injection Performance in Yucatan Miniature Pigs with and without Human Hyaluronidase and Auto-injector Tolerability in Humans

Recombinant human hyaluronidase PH20 (rHuPH20) facilitates subcutaneous (SC) delivery of co-administered therapeutic agents by locally and transiently degrading hyaluronan in the SC space, and can be administered with therapeutics using a variety of devices. Two SC delivery studies were carried out to assess auto-injector (AI) performance, each in 18 Yucatan miniature pigs. Abdominal injections were administered using three auto-injectors of 1 mL (AI1) and 2 mL (AI2 and sAI2) with different injection speeds and depths (5.5–7.5 mm) and two pre-filled syringe (PFS) devices of 1 and 2 mL. The injection included a placebo buffer with and without rHuPH20 to evaluate the effect of rHuPH20 on SC injection performance. The feasibility of using similar devices to deliver a placebo buffer in humans was investigated. rHuPH20 was not studied in humans. In miniature pigs, postinjection swelling was evident for most PFS/AI injections, particularly 2 mL. Swelling heights and back leakage were typically lower with rHuPH20 co-administration versus placebo for most device configurations (1 or 2 mL PFS or AI). Auto-injections with versus without rHuPH20 also resulted in reduced swelling firmness and faster swelling resolution over time. Slow injections with rHuPH20 had shorter and more consistent injection time versus placebo. In humans, minimal injection site swelling and negligible back leakage were observed for 2-mL injections of placebo, while more erythema was observed in humans versus miniature pigs. Even at high delivery rates with PFS or AI, the addition of rHuPH20 resulted in improved SC injection performance versus placebo in miniature pigs.