The medication locker for a long term space flight may need to be larger than currently thought, a study in the The AAPS Journal concludes. One of the first publications from the Stability of Pharmacotherapeutic and Nutritional Compounds (Stability) project determined that after 28 months of storage on the International Space Station some medications degraded faster than controls stored in as similar environment as possible on the ground.
One of the authors, Lakshmi Putcha, Ph.D, said the differences between the ground and control environments “include, but are not limited to, ambient radiation, excessive vibrational forces, multiple gravity environments and carbon dioxide enrichment; this is in addition to unconventional packaging, resupply operations and other unknowns.”
From the abstract:
After stowage for 28 months in space, six medications aboard the ISS and two of matching ground controls exhibited changes in physical variables; nine medications from the ISS and 17 from the ground met the United States Pharmacopeia (USP) acceptance criteria for API content after 28 months of storage. A higher percentage of medications from each flight kit had lower API content than the respective ground controls. The number of medications failing API requirement increased as a function of time in space, independent of expiration date. The rate of degradation was faster in space than on the ground for many of the medications, and most solid dosage forms met USP standard for dissolution after storage in space. Cumulative radiation dose was higher and increased with time in space, whereas temperature and humidity remained similar to those on the ground. Exposure to the chronic low dose of ionizing radiation aboard the spacecraft as well as repackaging of solid dosage forms in flight-specific dispensers may adversely affect stability of pharmaceuticals.
One notable result from the full article is the degradation of the ground-based, or control, medications. Of the 33 medications tested, only 17 maintained what the authors considered to be adequate potency by the end of 28 months, and several degraded before the manufacturers’ expiration date. In particular, clavulanate, usually added to penicillin to prevent antibiotic resistance, was found to degrade almost immediately, and paradoxically held up better in the space-flown samples. The authors comment on this and note that these results are shorter than those found in the FDA/DOD Shelf Life Extension Program, probably because the NASA samples were re-packaged.
Aside from medications, the Stablilty study also looked at the properties of various foods. So, along with more or different meds, the food locker might need to be bigger as well. None of these results tell us what food and medications produced in space might be like, only what factors need to be taken into account for stores brought along from Earth.
NASA press release: Preparing to Stock the Medicine Cabinet for Long-Duration Missions