Comparative Analysis of Pharmaceutical Content Following Spaceflight and Vacuum Exposure During Commercial Extravehicular Activity

Abstract

Introduction

Pharmaceutical stability is a key concern for space missions, where radiation, microgravity, and prelaunch repackaging may accelerate drug degradation. While prior studies examined medications in environmentally controlled spacecraft, data on vacuum exposure are limited. The Polaris Dawn mission provided an opportunity to evaluate drug content following depressurization of the Dragon spacecraft and exposure to the vacuum of space during extravehicular activity.

Methods

Nineteen medications (13 repackaged solid, 6 liquid) flew as part of the SpaceX medical kit and were analyzed with lot-matched terrestrial controls. All samples underwent ultra-performance liquid chromatography mass spectrometry analysis upon return. The primary outcome was the percent difference in active pharmaceutical ingredient (API) between vacuum exposure and ground controls. A secondary outcome was the absolute API content expressed as a percentage of labeled dosage.

Results

Seventeen of the 19 flown medications demonstrated a < 5% mean API difference between spaceflight and lot-matched terrestrial controls, remaining within the prespecified threshold for clinical significance. Seven medications showed statistically significant differences (p < 0.05) between the 2 groups, yet all but one medication remained within this 5% range. Against the narrow 95%–105% of labeled dosage criterion, 10 ground controls and 11 spaceflight-exposed medications fell outside this range. Expanding to the broader 80%–120% range, nearly all medications were within acceptable limits.

Conclusions

Short-duration spaceflight with vacuum exposure resulted in modest differences in drug content between spaceflight and terrestrial samples. However, high concordance suggests no clinically meaningful degradation, supporting the feasibility of repackaged pharmaceuticals for commercial and exploratory missions.