Table 1 Factors affecting the translation of terrestrial pharmaceutical stability to the space environment
Factor | Translational limitation |
|---|---|
Mechanisms of damage: direct versus indirect ionization | Primary damage from impact of heavy ions on substrate, and differential generation of free radicals |
Dose delivery | Dose and dose-rate impacts formation of free radicals, catalysis of chemical reactions, and energy transfer |
Radiation type | Different response to gamma, x-ray, electron beam, proton, heavy ion, and mixed ion exposures |
Intravehicular environment simulation | Intravehicular radiation spectra markedly different depending on hull or shielding material |
Limited translational space research | Few studies, each with numerous confounders, poor ground controls, poor sample size, and delayed or limited processing |
Formulation sensitivity | Formulations of very similar drugs can have significant variation of response to radiation exposure; alterations in radiation response of liquid, solid, or powder formulations |
Spaceflight confounders | Shelf-life concerns, pharmaceutical age, repackaging and materials interactions, and alterations of pharmacokinetics/pharmacodynamics in flight |
Limited research plans | Rapid progression to exploration spaceflight (with lunar and Mars missions in planning stages), and poor understanding of risk profile for informed decision-making |
