Design Verification Testing for Prefilled Syringes: A Structured Best-Practice Framework

Background: Prefilled syringes (PFSs) are increasingly used for self- and assisted administration of high-value parenterals, yet design verification (DV) planning remains challenging due to overlapping drug, device, and combination product expectations, as well as limited harmonization of device components. To the best of our knowledge, there is no publication providing an end-to-end DV approach for developers. This work aims to provide a best-practice template for structuring and justifying DV programs for PFSs, with the explicit intent of improving transparency and offering practical clarity to development teams navigating regulatory and technical complexity. Methods: A risk-based DV approach is presented for an exemplary 1 mL long staked needle glass PFS intended for subcutaneous administration of a surrogate solution representative of a high-concentration biologic. The approach starts with the design inputs which were derived from intended use, user requirements, and the drug's quality target product profile (QTPP), then translated into design outputs including Essential Drug Delivery Outputs (EDDOs). These outputs were proven by executing drug-independent and simulated drug-dependent DV tests using ISO- and pharmacopeia-aligned methods, including defined sampling, and real-time/accelerated aging. Results: A best-practice DV approach is presented, including test results across the evaluated functional, mechanical, and integrity endpoints. Conclusions: The presented approach provides a transferable DV template linking intended use to acceptance criteria, sample size rationale, and test selection. As a best-practice contribution, it supports more consistent, defensible DV planning for PFSs and may reduce ambiguity in the interface between drug and device development expectations.