Master of Science in Biological and Agricultural Engineering (MSBAE)
Biological and Agricultural Engineering
Alpha-tocopherol (áT) is a hydrophobic, antioxidant molecule shown to prevent or retard the effects of free radicals associated with diseases. It is hypothesized that the bioavailability of áT can be improved when entrapped in PLGA (Poly lactide-co-glycolide) and PLGA-Chi (PLGA-Chitosan) nanoparticles and that the mucoadhesive properties of chitosan may enhance absorption more than PLGA alone. PLGA and PLGA-Chi NPs synthesized with PVA as surfactant were characterized by measuring entrapment efficiency, size, PDI, and zeta potential when suspended in DI water. Nanoparticle physical stability was evaluated via NP exposure to environmental pH ranging from 2.5-9. Chemical stability of entrapped áT was also investigated by exposing particles to simulated GI (gastro-intestinal) environments for 48 hours, and release kinetics were measured in these conditions for 72 hours. Pharmacokinetic studies were conducted by administering PLGA (áT) NPs, PLGA-Chi (áT) NPs, and free áT in a flour, water, and corn oil slurry via oral gavage in rats. Blood samples were collected over 72 hours. Entrapment efficiency was 95.4 ± 9.85%, for PLGA NPs and 77.95 ± 1.51% for PLGA-Chi NPs. The size and zeta potential of the two particle systems were 97.87 ± 2.63 nm and -36.2 ± 1.31 mV for PLGA(áT) NPs, and 134 ± 2.05 nm and 38.0 ± 2.90 mV for PLGA-Chi (áT) nanoparticles in DI water. PLGA(áT) NPs showed a change in size of only 4 nm in the pH range of 2.5-9, while PLGA-Chi(áT) nanoparticles revealed a 46 nm change in size in pH 2.5-9. Entrapped áT showed no degradation in GI conditions over 48 hours. Release kinetics also showed no release of the áT from either NP system over 72 hours. Bioavailability of nanodelivered áT was improved as indicated compared to the free áT up to 170% and 121% for PLGA and PLGA-Chi NPs, respectively. These findings revealed that both delivery systems increased bioavailability of áT, but chitosan did not improve uptake of áT, as hypothesized.
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Simon, Lacey Caroline, "Bioavailability of Alpha-Tocopherol Entrapped in Poly (lactide-co-glycolide) (PLGA) and PLGA-Chitosan Nanoparticles" (2014). LSU Master's Theses. 2290.