Synthetic cathinones represent threatening and high abuse-potential designer drugs. These are analogs of cathinone (the b-keto analog of amphetamine (AMPH)) a naturally occurring stimulant found in the plant Catha Edulis. Methcathinone (MCAT) was the first synthetic analog of cathinone to be identified in 1987 by Glennon and co-workers and it exerted its action primarily through the dopamine transporter (DAT). Most central stimulants exert their action via monomaine transporters by causing either the release (e.g. cathinone analogs such as MCAT) or by preventing the reuptake (e.g. cocaine) of the neurotransmitter dopamine (DA) thus increasing the extracellular synaptosomal concentration of this neurotransmitter. In 2010, a new class of designer cathinone-like drugs called ‘bath salts’, initially a combination of methylenedioxypyrovalerone (MDPV), methylone (methylenedioxymethcathione, MDMC) and mephedrone (MEPH), soared to popularity. It caused extremely detrimental side effects; it was exceedingly popular for its recreational use and posed a threat to public health. At the time, their mechanisms of action were unknown. Our group identified that MDPV produced actions distinct from other cathinone analogs (i.e., it was identified as the first cathinone-like compound to act as a reuptake inhibitor at the dopamine transporter (DAT)). These findings suggested that not all cathinone-like compounds act uniformly and this insinuated that unique structural features on the cathinone scaffold might contribute to different effects at the transporter level. The overall goal of this project was to study the mechanisms of action of synthetic cathinones (including ‘bath salts’) at the monoamine transporters. We investigated the contribution of each of various structural features on the cathinone scaffold (i.e, the terminal amine, a and b positions, and the phenyl ring). We also constructed homology models of the human dopamine and serotonin transporters (hDAT and hSERT respectively) to help explain differences in selectivity between the neurochemical and behavioral aspects of DAT and SERT. Overall we found that structural features contributed to similar or distinctive mechanisms of action and also contributed to selectivity at monoamine transporters. Our studies provide information that can be useful to drug and health regulatory agencies to help prevent, treat, or curb the future abuse of such drugs.

C-terminal binding proteins (CtBPs) are transcriptional co-repressors involved in developmental processes, and also implicated in a number of breast, ovarian, colon cancers, and resistance against cancer chemotherapy. CtBP is a validated novel potential anti-cancer target. In this project we sought to develop potent and selective small-molecule inhibitors of CtBP. Using a combination of classical medicinal chemistry and modern computational approaches, we designed a potent inhibitor HIPP (hydroxyimino-3-phenylpropanoic acid) that showed an IC50 of 0.24 μM against recombinant CtBP. Further elucidation of the structure-activity relationship (SAR) of HIPP led to the design of more potent inhibitors 3-Cl HIPP (CtBP IC50 = 0.17 μM) and 4-Cl HIPP (CtBP IC50 = 0.18 μM). These compounds also showed inhibition in HCT-116 colon cancer cells with GI50 values ~ 1-4 mM. The compounds showed no off-target toxicity against a closely related protein. This is a starting point for the development of CtBP inhibitors as anti-cancer therapeutics. The second part of this dissertation focuses on C–H activation chemistry. C–H activation is the most atom-economical method of introducing complexity into a molecule, even at late stages of drug/product development. We have used solid-supported palladium nanoparticle catalyst (Pd-MWCNT) to investigate the scope of C–H activation reactions it can catalyse. Pd-MWCNT was found to efficiently catalyse N-chelation directed C-H activation reactions – halogenations, oxygenations and arylations. The turn-over numbers for these reactions were significantly higher than that of the reported homogenous catalyst. The added advantages of reuse/recyclability of catalyst, low contamination of metal in the final product make this catalyst very attractive on an industrial scale. This work serves as a foundation for the further development of Pd-MWCNT catalyst in late-stage synthesis of drugs and/or diversification of products.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the leading cause of dementia, affecting ~5.2 million Americans. Current FDA approved medications provide mainly symptomatic relief and there are no agents available to delay or cure this disease. Multiple factors such as amyloid-β aggregates, dyshomeostasis of biometals, oxidative stress, and neuroinflammation have been implicated in the development of AD. Even though significant advances have been made in understanding the mechanisms leading to AD, the exact etiology still remains elusive. Given AD’s multifactorial nature, a multifunctional strategy of small molecule design would help to identify novel chemical templates. Recently our lab has developed hybrid molecules of curcumin and melatonin that exhibited potent neuroprotective ability in various AD models. Further modifications identified a lead compound with potent neuroprotective and antioxidative activity in MC65 cells, while also establishing the hybrid strategy as a viable approach in providing unique chemotypes with novel pharmacology. Further preliminary biological studies suggest that the lead is orally available and exhibits multifunctional properties both in vitro and in vivo on AD pathologies, thus strongly encouraging further structural examination. Herein, we report the structural exploration of this chemical template through structure-activity relationship studies at three domains: the phenyl domain, α,β-unsaturated β-ketone amide domain, and the indole domain. Collectively, the results show that the chemical space around the curcumin portion doesn’t favor electronic or steric/hydrophobic interactions, but might favor pi-pi (π-π) and hydrogen-bond interactions. Additionally, the α,β-unsaturated β-ketone amide domain is not as important as the linearity of the β-ketone acetamide. Moreover, the results indicate that a free rotatable β-OH might be the actual moiety that is important for the observed biological activity through favorable hydrogen bonds. Finally, steric interactions are not favored in the chemical space surrounding the indole nitrogen, suggesting that hydrogen bond interactions are required for the observed neuroprotective activity. Conversely, a hydrogen bond acceptor is necessary at the 5-position of the indole ring and bulky substitutions can be accommodated, with restrictions, suggesting steric tolerance and hydrophobic interactions at this position. These modifications have yielded a series of novel compounds that are capable of modifying AD pathology while shedding further light onto the chemical scaffold thus warranting future investigations into the development, optimization, and characterization of these curcumin/melatonin hybrids as potential treatments for AD.

This study was aimed at the development of novel CB1 cannabinoid receptor antago­nists that may have clinical applications for the treatment of cannabinoid and psychostimulant addiction. The rationale for the design for our target was to incorporate a bioisosteric 1,2,3-triazole ring into the vicinal diaryl group revealed in the prototypical antagonist/inverse agonist SR141716 (Rimonabant) that was pre­sumed to interact with a unique region in the CB1 receptors. Based on our prelimi­nary results we identified a novel series of 1,2,3-triazole ester and keto deriva­tives as lead compounds for biological evaluation. Here in the design rationale, syn­thesis and CB1 receptor affinity for a series of 4,5-diaryl-1-substituted-1,2,3-triazoles of ester and ketones is described. These derivatives were synthesized via a one-pot regiospecific click/acylation reaction sequence from 1-azido-2,4-dichlorobenzene and commercially available arylacetylenes. From the structure-activity studies the 5-(4-chlorophenyl) congeners exhibited the most potent CB1 receptor affinities relative to other 5-(substituted-phenyl) moieties. The 1-(2,4-dichlorophenyl)-5-(4-chlorophenyl)-4-propylcarbonyl-1,2,3-triazole (­31a) was found to be the most potent (Ki = 4.6 nM) CB1 receptor ligand of the series and exhibited high CB1 selectivity (CB2/CB1 = 417). The triazole ester 31a was further characterized as a cannabinoid antagonist in locomotor-activity studies by blocking the locomotor-reducing effects of cannabinoid agonist WIN55,212-2. In addition, unlike the prototypical cannabinoid antagonist SR141716A (Rimonabant), the triazole ester 31a did not exhibit increased activity in locomotor activ­ity studies, thus indicating the potential for a neutral antagonist profile.

Azetidine is a four-membered nitrogen-containing heterocyclic ring that has recently received a great deal of attention as a molecular scaffold for the design and preparation of biologically active compounds. Structure-activity studies employing functionalized azetidines have led to the development of variety of drug molecules and clinical candidates encompassing a broad spectrum of biological activities. Herein, the synthesis a novel series of 3-aryl-3-arylmethoxyazetidines is described. Selected 3-aryl-3-arylmethoxyazetidines were evaluated for their binding affinity to multiple monoaminergic transporters for the potential treatment of methamphetamine addiction. It was discovered that this scaffold exhibits high binding affinity (nM) for both the serotonin and dopamine transporters. In addition, a new method was developed for the synthesis of 3,3-diarylazetidines. This new approach provides a facile and efficient method to synthesize a variety of diaryl heterocycles including 3,3-diarylazetidines, 3,3-diarylpyrrolidines, and 4,4-diarylpiperidines in moderate to good yields.

In this study, three different chromatographic column chemistries (C18, Pentafluorophenyl (PFP), Hydrophilic Interaction Chromatography (HILIC)) were compared under optimal conditions to determine which stationary performed best in the separation and detection of a mixture of opioids using LC-MS. Furthermore, these stationary phases were examined in three different column technologies – traditional silica, porous shell, and porous polymer (PRP). The PRP column had the best peak shape for all 13 opioids and dominated for later-eluting compounds. In terms of column reproducibility, the Hamilton C18 column had the lowest %RSD values. The Kinetex HILIC produced the most theoretical plates and best resolution for polar compounds as did the Hamilton C18 for nonpolar compounds. Finally, Kinetex PFP and Hamilton PRP both demonstrated themselves as viable alternatives to the C18 column chemistry for analysis of this drug class.

Sunitinib, an oral vascular endothelial growth factor receptor, is a first-line option for metastatic renal cell carcinoma and widely used in clinical practice. Despite the proven benefit of sunitnib in metastatic renal cell carcinoma, patients may suffer from a variety of adverse events including hypertension, fatigue, hypothyroidism, hand?foot skin reactions, rash, depigmentation, and myelosuppression. Myelosuppression is usually mild, transient and resolves during the two weeks at the end of each cycle where no drug is taken. We present a case of severe and early grade 3 neutropenia and thrombocytopenia occurring two weeks into a six-week cycle. Because of the extreme nature of the toxicity, CYP 3A4 polymorphisms were explored. The patient was found to be heterozygous for CYP 3A4*22, at least partially explaining the early-onset and severity of myelosuppression. This pharmacogenetics information resulted in a rechallenge of dose-reduced sunitinib, which was well tolerated by the patient. The current state of pharmacogenomics concerning sunitinb is also presented, and the need for greater research in this area is highlighted.

Hospitals within the State of Kentucky were surveyed to determine if the size of the hospitals influence the frequency of potential meal interference with the administration of oral antibiotics where the "empty stomach" concept must be fulfilled. One hundred and ten hospitals responded to the mailed survey. Of the responding hospitals 103 were short-term and 7 were long-term hospitals. The frequency of conflict was greater for nourishments than with meal interference. Ninety-three and six tenths percent or 103 answered yes when asked if all patients received nourishments on request. The conflicts of potential meal interference ranged from 15 to 40 percent and with nourishments 41 to 82 percent. A significant relationship was observed between hospital size and potential meal interference, and Chi-square values were statistically significant at the .05 level.

The proteasome is a large protein complex which is responsible for the majority of protein degradation in eukaryotes. Following FDA approval of the first proteasome inhibitor bortezomib for the treatment of multiple myeloma (MM) in 2003, there has been an increasing awareness of the significant therapeutic potential of proteasome inhibitors in the treatment of cancer. As of 2017, three proteasome inhibitors are approved for the treatment of MM but in clinical trials with patients bearing solid tumors these existing proteasome inhibitors have demonstrated poor results. Notably, all three FDA-approved proteasome inhibitors rely on the combination a peptide backbone and reactive electrophilic warhead to target the proteasome, and all three primarily target the catalytic subunits conferring the proteasome’s chymotrypsin-like (CT-L) activity. It is our hypothesis that compounds with non-peptidic structures, non-covalent and reversible modes of action, and unique selectivity profiles against the proteasome’s distinct catalytic subunits could have superior pharmacodynamic and pharmacokinetic properties and may bear improved activity against solid tumors relative to existing proteasome inhibitors. In an effort to discover such compounds we have employed an approach which combines computational drug screening methods with conventional screening and classic medicinal chemistry. Our efforts began with a computational screen performed in the lab of Dr. Chang-Guo Zhan. This virtual screen narrowed a library of over 300,000 drug-like compounds down to under 300 virtual hits which were then screened for proteasome inhibitory activity in an in vitro assay. Despite screening a relatively small pool of compounds, we were able to identify 18 active compounds. The majority of these hits were non-peptide in structure and lacked any hallmarks of covalent inhibition. The further development of one compound, a tri-substituted pyrazole, provided us with a proteasome inhibitor which demonstrated cytotoxic activity in a variety of human solid cancer cell lines as well as significant anti-tumor activity in a prostate cancer mouse xenograft model. We have also evaluated the in vitro pharmacokinetic properties of our lead compound and investigated its ability to evade cross-resistance phenomena in proteasome inhibitor-resistant cell lines. We believe that our lead compound as well as our drug discovery approach itself will be of interest and use to other researchers. We hope that this research effort may aid in the further development of reversible non-peptide proteasome inhibitors and may eventually deliver new therapeutic options for patients with difficult-to-treat solid tumors.

Intracellular polymerization of deoxygenated sickle hemoglobin (Hb S) remains the principal cause of the pathophysiology associated with sickle cell disease (SCD). Naturally occurring and synthetic allosteric effectors of hemoglobin (AEH) have been investigated as potential therapeutic agents for the treatment of SCD. Several aromatic aldehydes, including vanillin, have been studied previously as AEHs for their antisickling activities. Specifically, these compounds form Schiff- base adduct with Hb to stabilize the oxygenated (R) state, increase Hb affinity for O2 and concomitantly prevent the hypoxia-induced primary pathophysiology of Hb S polymerization and RBC sickling, in turn, ameliorating several of the cascading secondary adverse effects. These compounds, however, undergo significant metabolism leading to suboptimal pharmacokinetic properties, e.g. short duration of pharmacologic action and low bioavailability. These drawbacks have severely hampered the use of aromatic aldehydes as AEHs to treat SCD. To counter these challenges, we designed and synthesized 14 novel compounds (PP- compounds) based on previously studied pyridyl derivative of vanillin. These modifications were expected to increase binding interactions with the protein and thus stabilize the Schiff-base adduct, as well as lead to perturbation of the surface-located F-helix that would stereospecifically destabilize polymer contacts. We investigated the in vitro pharmacokinetic/pharmacodynamic properties of these newly synthesized compounds to ascertain sustained binding and modification of normal human Hb. Subsequently, we conducted in vitro screening assays to test for inhibition of sickling, modification of Hb to the high-affinity form, as well as for a direct left-shift in oxygen equilibrium curves (OEC). Three selected compounds, PP6, PP10, and PP14, that demonstrated not only high antisickling activity but also showed sustained pharmacologic action were chosen for preliminary in vivo studies. Our results showed maximal levels of Hb modification, which were sustained for the entire 24 h experimental period. In contrast, TD-7 after reaching maximum effect at 1 h gradually decreased in potency and at 24 h has lost 45% of its activity, consistent with the low bioavailability of this compound. These findings suggested that our modifications appeared to successfully limit drug metabolism in red blood cells. Most of these compounds showed almost complete inhibition of sickling at 2 mM concentration; with significant modification of Hb to a higher affinity Hb as well as an increase in O2 affinity of Hb. Interestingly, while TD-7 demonstrated a clear linear correlation between its ability to increase Hb-O2 affinity and antisickling activity, PP2, PP3, PP6, PP9, PP10, and PP14, showed a weak correlation between these parameters. In fact, these compounds demonstrated high antisickling effect despite only marginally increasing Hb affinity for O2. This observation indicated that these compounds possibly exhibit the dual mechanism of antisickling activity. We hypothesize that their secondary mechanism of action is due to interactions with the surface located αF-helix that would lead to direct or stereospecific inhibition of polymer formation. To establish the mode of interaction with Hb, we further conducted x-ray crystallography studies and co-crystallized PP2, PP6, PP9 and PP11 with CO-liganded Hb. Our studies showed that these compounds bind in symmetry-related fashion at the α-cleft of Hb to form Schiff-base adducts with the N-terminal Val1 and showed direct interactions with the F-helix which overall enhanced interactions with Hb. PP6, PP10, and PP14 demonstrated significant in vivo modification of intracellular Hb in mice after IP administration, with increasing levels from 1 h to the 6 h experimental period. They also showed corresponding changes in O2 affinity observed at 3 h and 6 h, compared to 0 h pre-treatment samples in vivo. Thus, our results establish these compounds as a novel, promising group of potent anti-sickling agents, demonstrate their proposed mechanism of action and provide proof-of-concept justifications for our structure-based approach to developing potent therapeutics for SCD.