Chemical Potency and Degradation Products of Medications Stored Over 550 Earth Days at the International Space Station

Abstract

Abstract. Medications degrade over time, and degradation is hastened by extreme storage conditions. 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. For this reason, medications stored on the ISS were returned to Earth for analysis. This was an opportunistic, observational pilot-scale investigation to test the hypothesis that ISS-aging does not cause unusual degradation. Nine medications were analyzed for active pharmaceutical ingredient (API) content and degradant amounts; results were compared to 2012 United States Pharmacopeia (USP) requirements. 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 1 time point and no control samples (samples aged for a similar period on Earth) were available. 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. 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. Limited, evidence-based extension of medication shelf-lives may be possible and would be useful in preparation for lengthy exploration missions. Only analysis of flight-aged samples compared to appropriately matched ground controls will permit determination of the spaceflight environment on medication stability.

Ergonomic Challenges for Astronauts during Space Travel and the Need for Space Medicine

“…6 medications changed their physical characteristics compared to 2 on Earth which may affect their efficacy. However, in another study analysis of drug degradation and chemical potency as defined by the API, showed that 8 out of 9 medications met USP criteria for achieving an acceptable API and did not identify unexpected degradation products [103].…”

“…There have been a number of excellent publications either as reviews [1,[82][83][84][85][86][87][88][89] or as original research, including publications which illustrate the effect of gravity on drug targets, processes which affect drug behavior in physiological systems [72,73,86,[89][90][91][92][93][94][95][96][97][98][99][100][101][102][103][104] and this section will summarise the major findings. When planning astronaut healthcare for a space mission, there are a number of basic considerations which are, in part dependent upon the duration of the mission;…”

“…All drugs administered were associated with adverse events which were manageable and most reports of drug ineffectiveness were reported after the first day of administration. Although there was a paucity of available information on drug effectiveness, these early findings stimulated investigation into understanding pharmacokineticpharmacodynamic relationships and whether the space environment per se may effect drug properties such as stability [83,[88][89][90]94,[101][102][103][104][106][107][108]. To date, there have been two published studies which have investigated the effect of space flight on the pharmacokinetics of the analgesic acetaminophen [paracetamol] [91,109] and a further study investigating the same parameters of the stimulant dextroamphetamine and the anti-emetic scopolamine [92].…”

Physicochemical Stability of Space Medicines

“…Photolabile drugs were more prone to degradation in space (Du et al 2011). Wotring evaluated stability of nine medicines after 550 days storage in ISS and found that though many pharmaceuticals met USP acceptance criteria for API content, they showed increase in percentage impurities (Wotring 2016). Chuong et al examined stability of vitamin B complex after storage in ISS and observed minute degradation in one of the brands of vitamin B 3 tablets (Chuong et al 2011).…”

Vitamin D in Space

“…It is unlikely to be possible to replace expired drugs on a long journey such as to Mars. Wotring failed to provide a complete guide to this issue because there was no control sample on the Earth and proposed more studies should be carried out [68].…”