However, some characteristics need to be known about space, specifically the challenges of being exposed to radiation. There are three different sources of radiation, of which the biggest one is the sun. This emits wavelengths of which the majority is in the form of ultraviolet radiation (UV). Occasionally, there are explosions on the surface of the sun which release energy in form of x-rays, gamma rays, protons, and electrons. This is what is known as a solar particle event, and it affects the astronaut’s health and equipment even if they are far from the Sun. There are particles in the earth’s magnetic field, and high-energy ions from elements, which can pass through a typical spacecraft or the skin of an astronaut (Perez, 2017).
Milli-Sievert (mSv) is a unit of measurement used for radiation. Astronauts are exposed to ionizing radiation with effective doses in the range from 50 to 2,000 mSv. 1 mSv of ionizing radiation is equivalent to about three chest x-rays. So, space radiation can make it feel like having 150 to 6,000 chest X-rays. As a result, the risk of having cancer increases by a thousandfold (Perez, 2017).
Effect of Microgravity and Radiation on Health
There are certain stress factors in space including microgravity and ionizing radiation which remove electrons from atoms in cells and tissues affecting the DNA and therefore resulting in the induction of various diseases including cancer, osteoporosis, deterioration of bone density, and loss of muscle mass (CDC, 2021).
Some of the physiological hazards that are caused due to microgravity include facial swelling and a 30% decrease in leg circumference. Deduction of blood volume and red blood cell quantity, and increased intracranial pressure are a result of UV exposure, along with loss of muscle mass and bone density, and neurodegenerative disease (Springel, 2013).
Now, focusing on the cardiovascular system, atherosclerosis is a probable disease which is when plaques of fatty material are on the arteries' inner walls, leading to cardiac conduction and valve abnormalities. Then it will lead to myocardial fibrosis, increasing the collagen volume of myocardial tissue, and it can end in heart failure (Meerman et al., 2021).
Pharmaceutical Formulations Best Fit for Space
Currently, there are some injectable medications to treat this, however, there are some disadvantages, such as an increased cost of payload transportation from Earth to space, it produces space pollution, requires specific storage conditions, and will probably need help from other people. Additionally, eye drops might not be the best drug delivery due to gravity and the difficulty this presents (Mehta & Bhayani, 2017).
Based on that, oral drug delivery would be a better option since pills are easy to carry, they do not require specific storage conditions, there is no need for additional equipment which will save a lot of money, it will produce less waste because it will dissolve in the body, and intake process is more preferred due to not having to be injected. However, oral drugs are not stable in the gastrointestinal tract due to the acidic environment present in the stomach. Based on that, a drug vehicle would be required to protect the antigen from the harsh gastric environment and overcome the mucin barrier. Ongoing research is trying to optimize the space medicines that can have a better outcome at minimal risk factors. Continuous research and experimentation are being carried out to observe the numerous health effects that have a possibility of occurring, including genetic disorders, organ failure, etc., and whether the developmental drugs can make any impact (Lee et al., 2017).
Ever since the early voyages to outer space, or even before that, people have always wondered about ways to colonize and sustain life in other areas of the galaxy to continue the predominant presence of Earthly life forms. With the aid of therapeutics advancement focusing on space health along with their positive progression in a simulated microenvironment, we are more hopeful than ever that with further research, leaving footsteps on the outside world is not far off from being a reality.
References
1. Centers for Disease Control and Prevention. (2021, June 29). Radiation studies: Ionizing radiation. Centers for Disease Control and Prevention. Retrieved April 2, 2023.
2. Lee, D.-Y., Nurunnabi, M., Kang, S. H., Nafiujjaman, M., Huh, K. M., Lee, Y.-kyu, & Kim, Y.-C. (2017). Oral gavage delivery of PR8 antigen with β-glucan-conjugated GRGDS carrier to enhance M-cell targeting ability and induce immunity. Biomacromolecules, 18(4), 1172–1179.
3. Meerman, M., Bracco Gartner, T. C., Buikema, J. W., Wu, S. M., Siddiqi, S., Bouten, C. V., Grande-Allen, K. J., Suyker, W. J., & Hjortnaes, J. (2021). Myocardial disease and long-distance space travel: Solving the radiation problem. Frontiers in Cardiovascular Medicine, 8.
4. Mehta, P., & Bhayani, D. (2017). Impact of space environment on stability of medicines: Challenges and prospects. Journal of Pharmaceutical and Biomedical Analysis, 136, 111–119.
5. Perez, J. (2017, April 13). Why space radiation matters. NASA. Retrieved April 2, 2023.
6. Springel, M. (2013, August 12). The human body in space: Distinguishing fact from fiction. Science in the News. Retrieved April 2, 2023.
7. Wiles, J. (2013, June 13). Why we explore. NASA. Retrieved April 2, 2023.