The QUOMET Project: Quantifying Shock Levels in Pharmaceutical Transport to Ensure Medication Safety

Background
The quality of pharmaceutical products can be significantly impacted by factors associated with transportation. Among these, temperature variations and mechanical stresses such as shocks and vibrations are crucial. Previous studies have demonstrated that proteins may alter their higher order structure due to air/liquid or solid/liquid interfacial stresses, which include hydrophobic interactions, charge variations, and mechanical stress (1). These modifications often lead to the formation of subvisible particles, posing significant challenges in drug quality assurance and stability.

Objective
This study aims to establish a reproducible, openly accessible measurement method to quantify the mechanical stresses experienced by medications during transport. By accurately measuring these stress levels, we can compare them with known data from the literature to make informed decisions.

Materials and Methods
A high-g accelerometer (ADXL375, Analog Devices^®) already integrated into ready-to-use boards (ADXL375 board, Adafruit^®) was used. A microcomputer (Raspberry Pi Zero 2W, Raspberry^®) was programmed in Python and interfaced with the accelerometers via the I2C bus. The sampling rate was set at 800 Hz. The magnitude of the shock force vector was calculated by taking the square root of the sum of the squares of its components across three axes (x, y, z).

Results and Discussion
Falls from heights of 25 cm exceeded 25g (245 m/s²) in at least one axis (x, y, or z) and 30g (310 m/s²) in terms of magnitude. These shock levels have been described as likely to induce the formation of subvisible particles in biotherapeutics (2). In contrast to transportation on foot, as well as via elevators and stairs, which did not result in accelerations significantly exceeding 1g ± 1g, the pneumatic tube system not only recorded numerous shocks exceeding 25g on certain routes but also posed challenges in measuring these accelerations, putting a strain on the monitoring equipment.

Conclusion
Our pneumatic tube system may expose medications to shock levels exceeding 25g, highlighting the need for cushioning medications with foam. Accurate and timely shock measurement, with a high sampling frequency (ms), is critical to accurately detect shocks. While establishing a direct correlation with actual impact remains challenging due to the diversity of pharmaceutical products, it is essential to define threshold shock levels and apply precautionary principles to ensure the safety of medication transportation.
(1) Li, J., Krause et al. (2019. AAPS J, 21(3), 44.
(2) Randolph, T. W., et al. (2015). J Pharm Sci, 104(2), 602–611.