Graduation Date

Spring 5-4-2019

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Programs

Medical Sciences Interdepartmental Area

First Advisor

Dr. Howard E. Gendelman

Abstract

Over 30 years of antiretroviral therapy (ART) has transformed human immunodeficiency virus type one (HIV-1) outcomes from certain death to a nearly complete and normal life. Though disease growth has slowed, the virus still creates substantial co-morbid diseases as well as social and economic burdens worldwide. Lack of success with curative efforts combined with shortcomings in global treatment remain to be properly addressed. The requirement for daily use of combination antiretroviral drugs (ARVs) in low to middle income countries - where the majority of the HIV-1 positive population resides - can lead to breaks in regimen adherence due to a lack of access to ARV, high cost, social stigma, and lack of disease awareness. Treatment breaks speed viral drug resistance and longer-term adverse events, ultimately shortening patient life-span. Hospital feedback in low to middle income countries indicates patient preference for a variety of treatment options, including long-acting (LA) strategies. The need for treatment and by extension curative options is paramount in HIV-1 research. With an eye toward the future of HIV treatment, our laboratories generated a platform for small molecule antiretroviral drug nanoformulations by creating potent hydrophobic lipophilic ARV prodrugs with stable long-term physicochemical properties. Herein, this platform is extended to multiple small molecule inhibitors intended for antiviral therapy and HIV-1 eradication. A small molecule inhibitor used in cancer treatment was chemically modified to prolong drug activity, then tested for anti-HIV activities in the context of immune therapy in curative efforts. Additionally, two nucleoside reverse transcriptase inhibitors (NRTI) were chemically modified to produce long-acting drug iterations. Prodrug nuceloTide (ProTide) technology was used to chemically alter the NRTIs. A tenofovir ProTide was constructed and formulated, increasing prodrug accumulation. Following the same strategy, a phosphoroamidate prodrug nucleotide (ProTide) of lamivudine (3TC), called (M23TC) was synthesized and nanoformulated (NM23TC). A single treatment of NM23TC in human monocyte-derived macrophages (MDM) with NM23TC showed increased drug uptake, retention, intracellular 3TC triphosphate (3TC-TP) and sustained antiretroviral activities for 30 days. Pharmacokinetic analysis of NM23TC administered to Sprague Dawley rats showed sustained prodrug levels in blood and tissues. Further, in vitro studies showed intact prodrug was released over a month from MDMs. When tested in CEM CD4+ T cells, the prodrug was shown to rapidly convert to its 3TC-TP. Taken together, a putative mechanism for extended delivery of active compound to viral cell targets was constructed. This mechanism was strongly supported when tested as a broad-spectrum agent in model for hepatitis B virus infection in humanized mice. A single intramuscular injection produced sustained antiviral activities for one month. Taken together, the approaches give validation to potential value of the platform of transforming daily medications into nanoformulated prodrugs for long-acting antiviral activities.

Available for download on Tuesday, April 21, 2020

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