Vial puncture mechanics with a mechanical assist device during anticancer drug compounding with a closed-system drug transfer device.

PURPOSE: Off-center and nonperpendicular vial puncture has been proposed as a potential contributor to rubber stopper push-in during needle insertion into closed-system drug transfer devices (CSTDs). However, quantitative evaluation of the puncture process remains limited. This study aimed to compare puncture mechanics during vial access between manual puncture and use of a mechanical assist device and to evaluate differences in the device effect across vial types. METHODS: Anticancer drug vials were compounded using NEOSHIELD with or without NS Spike Assist. Vials were randomly sampled (maximum four per compounder), targeting 70 vials per vial type in each study group. Puncture distance from center (D1), puncture angle (A1), and radial deviation within the rubber stopper (drad) were measured microscopically. RESULTS: A total of 980 vials were analyzed. The assist device shifted A1 toward perpendicular across most vial types and mitigated angular deflection associated with off-center entry (larger D1), with A1 clustering near 90° across a wide range of D1 values. Changes in D1 varied by vial type. drad was predominantly negative with manual puncture but shifted toward neutral or positive with the assist device in several vial types; for doxorubicin 50 mg vials, drad increased from -0.046 to 0.031 mm (ΔHL 0.079 mm, 95% CI 0.021-0.146; P = 0.008). CONCLUSIONS: The assist device for CSTDs stabilized puncture trajectory through the rubber stopper, yielding a more perpendicular and controlled intrastopper pathway than manual puncture. The practical significance of this trajectory stabilization for rubber stopper push-in and occupational exposure remains to be determined.