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Dissertation LR FINAL.pdf (37.77 MB)

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Controlled Release System for Localized and Sustained Drug Delivery Applications

Rodriguez, Lidia Betsabe
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1365107103

Abstract Details

2013, Doctor of Philosophy, University of Toledo, Biomedical Engineering.
Current controlled release formulations has many drawbacks such as excess of initial burst release, low drug efficiency, non-degradability of the system and low reproducibility. The present project aims to offer an alternative by developing a technique to prepare uniform, biodegradable particles (~19 µm) that can sustainably release a drug for a specific period of time. Chitosan is a natural polysaccharide that has many characteristics to be used for biomedical applications. In the last two decades, there have been a considerable number of studies affirming that chitosan could be used for pharmaceutical applications. However, chitosan suffers from inherent weaknesses such as low mechanical stability and dissolution of the system in acidic media. In the present study, chitosan microparticles were prepared by emulsification process. The model drug chosen was acetylsalicylic acid as it is a small and challenging molecule. The maximum loading capacity obtained for the microparticles was approximately 96%. The parameters for the preparation of uniform particles with a narrow size distribution were identified in a triangular phase diagram. Moreover, chitosan particles were successfully coated with thin layers of poly lactic-co-glycolic acid (PLGA) and poly lactic acid (PLA). The performance of different layers was tested for in vitro drug release and degradation studies. Additionally, the degradability of the system was evaluated by measuring the weight loss of the system when exposed to enzyme and without enzyme. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and inductively coupled plasma optical emission spectrometry (ICP-OES) were used to characterize the controlled release system. Additionally, the in vitro drug release was monitored by ultraviolet-visible spectrophotometry (UV-Vis) and liquid chromatography mass spectrometry (LC-MS). The results obtained from this project showed that it is possible to prepare biodegradable microparticles with a uniform size distribution and high drug loading efficiency. However, this could only be achieved with a hybrid system consisting of chitosan matrix interior and then exterior coating of PLGA or PLA. A two layer coating of PLGA 50:50 was shown to be optimal with sustainable controlled drug release for almost 5 days and with 91% of degradation (weight loss) in 8 weeks.
Arunan Nadarajah, PhD (Committee Chair)
184 p.
Biomedical Engineering; Biomedical Research; Chemical Engineering; Materials Science
chitosan; controlled; aspirin; sodium tripolyphosphate; poly lactic acid; poly lactic co glycolic acid; poly glycolic acid; degradation; release

Recommended Citations

Citations

  • Rodriguez, L. B. (2013). Controlled Release System for Localized and Sustained Drug Delivery Applications [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1365107103

    APA Style (7th edition)

  • Rodriguez, Lidia. Controlled Release System for Localized and Sustained Drug Delivery Applications. 2013. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1365107103.

    MLA Style (8th edition)

  • Rodriguez, Lidia. "Controlled Release System for Localized and Sustained Drug Delivery Applications." Doctoral dissertation, University of Toledo, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1365107103

    Chicago Manual of Style (17th edition)

toledo1365107103
549
© 2013, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.
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