(509d) Polyampholyte Microspheres for Extended Drug Delivery

During prolonged space travel, astronauts experience deficiency in vitamin D due to lack of sunlight and they are required to take supplements to overcome this deficiency. Due to the current vitamin D delivery vehicles, the travelers must take the drug daily to maintain the same levels found in Earth-bound people. This results in an increased payload that is required to be sent with the astronauts. Nonfouling polymers are being looked at as a method of drug delivery because they have the potential for extended drug release without the body’s natural immune response clearing the drug from the blood stream. In this study, we specifically look at polyampholyte microgels which are a class of polymers made up of equimolar positively and negatively charged monomer subunits. They have demonstrated ability to resist nonspecific protein adsorption, deliver biomaterials to the body, and they have tunable mechanical properties. A piezoelectric droplet-on-demand generator was built to produce polymer microspheres composed of a 1:1 molar ratio of [2-(acryloyloxy)ethyl] trimethylammonium chloride (TMA, positively charged) and 2-carboxyethyl acrylate (CAA, negatively charged) monomers. The generator included an inner needle that could inject drugs into the droplets as they formed. The release kinetics of vitamin D was characterized, and the stability of the microspheres was demonstrated in biological media. The results demonstrated the potential of polyampholyte microspheres to be used as a drug delivery vehicle for space travelers.