Show simple item record

dc.contributor.advisor Katz, David F en_US
dc.contributor.author Geonnotti, III, Anthony Robert en_US
dc.date.accessioned 2008-08-01T12:53:13Z
dc.date.available 2008-08-01T12:53:13Z
dc.date.issued 2008-04-21 en_US
dc.identifier.uri http://hdl.handle.net/10161/648
dc.description Dissertation en_US
dc.description.abstract <p>There were 2.5 million people newly infected with HIV in 2007, clearly motivating the need for additional novel prevention methods. In response, topical vaginal antimicrobials, or microbicides, are being developed. These products aim to stop HIV transmission through local, vaginal delivery of antiviral compounds. To succeed, microbicides require a potent active compound within a well-engineered delivery vehicle.</p><p>A well-engineered delivery vehicle provides an antiviral compound with the greatest opportunity to interact with HIV and/or infected cells, thereby increasing overall microbicide effectiveness. The theoretical and experimental investigations within this dissertation are concerned with the study of HIV and active compound transport within microbicide delivery vehicles and with the mechanisms by which these transport processes can be affected to maximize viral neutralization. To initially investigate the factors contributing to microbicide effectiveness, a combined pharmacokinetic and pharmacodynamic model of HIV transport and neutralization within a microbicide product was created. Model results suggested that thin (~100µm) layers of microbicide product may protect against HIV infection. Model results also indicated that a specific and engineerable property of delivery vehicles - the ability to restrict viral transport - may increase the overall effectiveness of a microbicide. Two new experimental assays were developed to test the hypothesis that delivery vehicles can slow viral transport. First, a novel methodology was created to measure particle diffusion over length scales relevant to microbicide delivery (50-500µm). Results showed that current vehicles significantly restrict the transport of small molecules and proteins. The second assay was designed to test HIV transport in a biologically relevant, layered (fluid-microbicide-tissue) configuration of a microbicide product in vivo; infectious HIV was placed above a thin layer of a microbicide delivery vehicle. Assay results showed that HIV transport is significantly slowed by two different placebo gels. This experimental confirmation of viral restriction in hydrogels, combined with the theoretical finding that viral restriction increased microbicide effectiveness, strongly motivates the future development of new delivery vehicles that intentionally slow viral transport. These new experimental methodologies can also be used to screen and compare future delivery vehicles to produce optimal microbicide products.</p><p>Finally, a two-dimensional, computational finite-element vaginal model was created to evaluate the transport of drugs from an intravaginal ring. This model determined that while IVRs may be effective in the delivery of antiviral compound, their performance is influenced by the flow of vaginal fluid. The analysis also warns about the potential for local toxicity. </p><p>Well-engineered delivery vehicles are an essential component to microbicide performance because they maximize the opportunities for active compounds to interact with and neutralize HIV. The studies in this dissertation demonstrate that delivery vehicles have a significant effect on active compound and HIV transport. To create an effective microbicide, vehicle effects on transport processes must be well understood, purposefully engineered, and carefully optimized to ensure maximal interactions between antiviral compounds and virus. Directed engineering of delivery vehicles contribute to the foundation for microbicide success.</p> en_US
dc.format.extent 5694810 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.subject Engineering, Biomedical en_US
dc.subject Biophysics, General en_US
dc.subject HIV en_US
dc.subject microbicide en_US
dc.subject diifusion en_US
dc.subject mathematical modeling en_US
dc.subject drug delivery en_US
dc.title Transport Phenomena in Anti-HIV Microbicide Delivery Vehicles en_US
dc.type Dissertation en_US
dc.department Biomedical Engineering en_US
duke.embargo.months 12 en_US
dc.date.accessible 2009-08-02T05:00:04Z

Files in this item

This item appears in the following Collection(s)

Show simple item record