Houston | Medicines do not degrade faster under extreme conditions in space compared to what is typically seen on Earth, according to a new analysis of medications stocked on the International Space Station (ISS).
While the ISS is regularly resupplied with medicines to replace those which have passed their expiry date, this may not be possible on exploration missions that travel to more distant points. On Earth, medicines degrade over time, particularly when exposed to light, oxygen or humidity. Researchers at the Baylor College of Medicine in US analysed nine medications which had been stocked on the ISS and returned to Earth unused after 550 days of storage in spaceflight.
The medications included sleeping aids, pain relievers, antihistamines, decongestants, an antidiarrhoeal, and an alertness drug. The medicines were returned to Earth and, upon arrival, they were kept under controlled conditions until analysis 3-5 months later.
Researchers then measured the quantity of active ingredients and degradation products present in the medicines and determined whether or not the ISS medicines were still viable after being stored in space. According to the 2012 US Pharmacopeia guidelines, four of the nine drugs were still viable up to eight months after officially expiring.
One medication met USP requirements five months after its expiration date. Another three medications met USP guidelines when they were tested three months before their expiry date. A dietary supplement/sleeping aid did not meet USP requirements eleven months after it had expired. No unusual degradation products could be identified in any of the tests, researchers said.