Time-Sensitive Medicine Dissolution in a Microgravity Environment Emulated by Acoustic Levitation

As humanity ventures beyond Earth, the challenges of space travel extend far beyond rocket science and astrophysics. Astronauts face extreme physiological stresses—cosmic radiation, muscle atrophy, bone loss, and cardiovascular strain. In deep-space missions, where medical resources are limited, ensuring reliable drug performance is critical. However, microgravity can alter how medications dissolve, absorb, and act within the body, potentially compromising their effectiveness. This study investigates medication dissolution in microgravity using an acoustic levitator, which suspends small samples without physical contact. A custom-built 40 kHz levitator was developed, capable of levitating objects up to 4.0 mm in diameter and 15 mg in mass, including powders, crystals, and liquid-medication mixtures. To assess dissolution rates, medicine and water were placed on the node for set intervals. Direct weighing was unreliable due to retained moisture, so controlled microwave heating evaporated the water, and the final mass was determined using differential weighing. Ground trials validated the methodology, producing dissolution rates consistent with literature. However, microgravity significantly altered dissolution rates. A mathematical model based on the Noyes-Whitney equation quantified these changes for the first time. Ibuprofen dissolved nearly twice as slowly, while Aspirin’s rate decreased by 29%, suggesting altered diffusion dynamics. This research lays the foundation for space-optimized pharmaceuticals, ensuring effective drug delivery in space. Beyond space travel, potential applications include pharmaceutical formulation advancements, improved drug delivery systems, and precision medicine technologies utilizing acoustic levitation for testing in low-gravity environments.