New Study Explores How Storage on ISS May Affect Medications
According to a new study published in the AAPS Journal , medication degradation in space does not differ from what is seen on the planet.
The International Space Station is featured in this image photographed by an STS 132 crew member on board the Space Shuttle Atlantis after the station and shuttle began their post-undocking relative separation. Undocking of the two spacecraft occurred on May 23, 2010. Image credit: NASA / Crew of STS 132.
Current procedures ensure that medications aboard the International Space Station (ISS) are restocked before their expiration dates, but resupply may not be possible on future long-duration exploration missions.
Medications degrade over time, particularly with exposure to light, oxygen, or humidity; and degradation is hastened by extreme storage conditions.
Although temperature and humidity conditions aboard the ISS are generally within ideal ranges for medicine storage on Earth, until now, there has been little evidence of how medicines might react to factors unique to spaceflight, such as microgravity and constant exposure to elevated radiation levels.
Dr Virginia Wotring of the Baylor College of Medicine’s Center for Space Medicine analyzed nine medications which had been stocked on the ISS and returned to Earth unused after 550 days of storage in spaceflight.
The medications were two sleep aids, two antihistamines/decongestants, three pain relievers, an antidiarrheal, and an alertness medication. Because the samples were obtained opportunistically from unused medical supplies, each medication was available at only one time point and no control samples were available.
The medicines were returned to Earth and, upon arrival, they were kept under controlled conditions until analysis 3-5 months later.
Dr Wotring measured the quantity of active ingredients and degradation products present in the medicines.
She then used 2012 United States Pharmacopeia (USP) guidelines to determine whether or not the ISS medicines were still viable after being stored in space.
According to the guidelines, one medication met USP requirements 5 months after its expiration date.
“Four of the nine (44% of those tested) medications tested met USP requirements 8 months post expiration. Another three medications (33%) met USP guidelines 2–3 months before expiration,” Dr Wotring said.
“One compound, a dietary supplement used as a sleep aid, failed to meet USP requirements at 11 months post expiration. No unusual degradation products were identified.”
“The findings suggest that further research is necessary before planning long-term space flights – such as missions to Mars – because missions like this won’t have the opportunity to restock medicines in the way that the ISS can,” Dr Wotring added.