What's the News: In long space flights, such as a mission to Mars, astronauts will have more time during which they could get injured or sick. And the same apparently goes for the medicine aboard spaceships: According to a NASA-funded study, medicines degrade faster in space than they do on Earth. As the researchers conclude in their paper, "this information can facilitate research for the development of space-hardy pharmaceuticals and packaging technologies." How the Heck:
The researchers studied outer space's effect on 35 different medications such as the infection-fighters amoxicillin and mupirocin ointment that are commonly used by astronauts by comparing boxes of drugs flown on the International Space Station with identical boxes kept in controlled conditions (same temperature and humidity) at the Johnson Space Center in Texas. One of the ISS boxes was flown in space for only 13 days and another for 28 months.
Once back on Earth, the scientists tested the drugs in several ways. Using the standard methods of assessing pharmaceutical stability, they measured the physical variables---including weight, color, odor, and others---of the solid medicines. They also used liquid chromatography to measure the drugs' Active Pharmaceutical Ingredient (API), which indicates how much of a substance is biologically active.
At the 28-month marker, the scientists recorded only two physical changes in the control medications, but six physical changes in the space-flown ones. And while 17 medications from the control group met the United States Pharmacopeia (USP) acceptance criteria for API, only nine of the space drugs met the standards. According to the researchers, "This reduction in potency of flight samples occurred sooner than the labeled expiration date for many formulations suggesting that storage conditions unique to the spacecraft environment may influence stability of pharmaceuticals in space."
What's the Context:
There are many reasons why the medications may have degraded faster in space than on Earth, from excessive vibrations to the effects of microgravity, but the authors suggest two major causes: radiation and the repackaging of drugs for spaceflight. The pre-flight repackaging of drugs may expose the drugs to oxygen or humidity variations, increasing the deteriorating effects of oxidation. Radiation in space can ionize medications, thereby damaging them.
The scientists may have studied the most common medications used by astronauts, but it still only represents "18% of the formulary flown on spaceflights."
Most Earth-only medicines are designed to stay active for a couple years after they're manufactured; but that's only if they're kept in dry, cool conditions hidden from direct sunlight.
NASA has been interested in the effect of drugs in space for a while; in 2009, it launched a drug-testing micro-satellite into space to measure the effects of anti-fungal drugs on yeast.
Not So Fast:
For as-yet-unknown reasons, one medication---the antibiotic clavulanate---degraded faster on Earth than it did in space.
And the researchers mention that, despite their findings, space does carry some benefits for drugs: With more carbon dioxide in the environment, it "may help minimise the degradation of those medicines prone to oxidation, such as adrenaline, vitamin C and vitamin A."
The Future Holds: Now the scientists want to study how the less powerful space drugs will affect human health. For example, does this mean that certain diseases that are easily treatable on Earth remain hazards in space? Reference: Brian Du, Vernie R. Daniels, Zalman Vaksman, Jason L. Boyd, Camille Crady and Lakshmi Putcha. "Evaluation of Physical and Chemical Changes in Pharmaceuticals Flown on Space Missions." The AAPS Journal. DOI: 10.1208/s12248-011-9270-0
Image: Brian Du et al.
