Cosmic-Ray Radiation Effects on Ibuprofen Tablet Formulation Inside and Outside of the International Space Station

Abstract In extreme environments people will have different needs for medicine(s). It is important, therefore, to know how medicine efficacy will be impacted by the environment. Ibuprofen is very widely used in tablet formulation in temperate climates on Earth. Via the first companion experiment inside the International Space Station (ISS) and outside ISS at the Multipurpose International Space Station Experiment (MISSE) platformwe give evidence that Earth-commercial ibuprofen tablets could fail in space, despite encasing in a commercial pharmacy aluminum-blister. We introduce the concept of ‘space medicines’, where solid-dosage forms are formulated with excipients, such as iron oxide, to protect the pharmaceutical active from accelerated degradation in spaceflight. We apply Earth radionuclide and photon experiments to simulate dose(s) in ISS and significantly greater, and establish the impact of alpha, beta and gamma rays. We demonstrate that tablet formulation protects from impact of alpha and beta rays; however, gamma rays decompose ibuprofen even when ‘masked’. Importantly, we show all rays decompose ‘unmasked’ pure ibuprofen. We report for the first time a systematic analysis, of nineteen (19) tablet compositions, inside and outside of ISS that permit determination of the effect of compositional changes of the tablet matrix. We confirm that the iron oxide-shielded tablets, according to our four-fold degradation descriptor rating, had ‘minimal’ reduction of ibuprofen content (10%); with one exception. The tablets exhibited much greater ibuprofen degradation (> 30-50%) outside ISS at the MISSE platform, which permits exposure to harsh conditions including extreme temperature fluctuation, ultraviolet radiation, highly reactive atomic oxygen, and micrometeoroids. Significantly, we find that the flavor has shielding potential, most likely because of radical scavenging. We conclude that efficacy of ibuprofen is adversely affected in space, and that effects will likely be exacerbated on missions to deeper space e.g., to moon and Mars.