Impact of Storage Orientation and Duration on Prefilled Syringe Performance: Break-Loose and Glide Forces, and Injection Time Across Multiple Time Points.

Abstract

This study investigates the dynamics of break loose glide force (BLGF) in prefilled syringes (PFS) and injection time in autoinjectors (AI) across different orientations and time points, focusing on their impact on drug delivery performance. PFS and Autoinjectors are pivotal in modern therapeutics, enabling precise administration of biologics, vaccines, and other sensitive pharmaceuticals. Patients with chronic conditions and individuals with limited dexterity requiring frequent self-administration, all benefit from devices that minimize BLGF to ensure consistent injection times. To explore the influence of storage orientation (tip-up vs. tip-down) and time on these devices, we conducted a comprehensive evaluation over a 12-month period supplemented by reference timepoint samples. Utilizing a dual-orientational framework, PFS and autoinjectors were stored under controlled conditions to assess orientation-dependent performance. Aged and empty samples served as reference controls. The study's primary metrics included BLGF, which is the initial force required to initiate plunger movement then enable injection along the barrel, and injection time. These parameters were analyzed using a calibrated Zwick/Roell mechanical tester under controlled environmental conditions.Key findings reveal statistically significant but not practically impactful effects of storage orientation on BLGF or injection time across all tested intervals. Minor time-based variations were noted, with BLGF shifts being less than 1 N and injection time deviations under 2 seconds. These changes indicated no practical significance or risk of out-of-specification performance. The Analysis of variance (ANOVA) analysis confirmed no evidence suggesting orientation affects functionality.This work demonstrates that short to mid-term storage conditions do not adversely affect device performance, providing critical assurance for manufacturers, regulators, and end-users. The study highlights the robustness of PFS and Autoinjectors against orientation and temporal changes, mitigating risks associated with handling variability and optimizing supply chain logistics. Future research should extend these findings to longer durations to confirm long-term stability.