Stability of Antimicrobial Drug Molecules in Different Gravitational and Radiation Conditions in View of Applications during Outer Space Missions

Abstract

The evolution of different antimicrobial drugs in terrestrial, microgravity and hypergravity conditions is presented within this review, in connection with their implementation during human space exploration. Drug stability is of utmost importance for applications in outer space. Instabilities may be radiation-induced or micro-/hypergravity produced. The antimicrobial agents used in space may have diminished effects not only due to the microgravity-induced weakened immune response of astronauts, but also due to the gravity and radiation-altered pathogens. In this context, the paper provides schemes and procedures to find reliable ways of fighting multiple drug resistance acquired by microorganisms. It shows that the role of multipurpose medicines modified at the molecular scale by optical methods in long-term space missions should be considered in more detail. Solutions to maintain drug stability, even in extreme environmental conditions, are also discussed, such as those that would be encountered during long-duration space exploratory missions. While the microgravity conditions may not be avoided in space, the suggested approaches deal with the radiation-induced modifications in humans, bacteria and medicines onboard, which may be fought by novel pharmaceutical formulation strategies along with radioprotective packaging and storage.

Keywords: antibiotics; drug stability; hypergravity; laser irradiation; microgravity; multiple drug resistance; non-antibiotics; pharmacokinetics/pharmacodynamics; photoactivated drugs; spaceflight environment.

Figure 1

Factors that could enhance the risk of infections and their transmission in the spaceflight environment. Alterations in astronauts’ microbial flora and bacterial physiology could lead to increased microbial contamination onboard. Changes in astronauts’ physiology as well as in physico-chemical properties of pharmaceuticals could influence pharmacokinetics and/or pharmacodynamics. Increased microbial virulence and decreased drug susceptibility could enhance antimicrobial resistance. Notations: $\uparrow$ increase; $\downarrow$ decrease.