Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by difficulty paying attention, impulsivity, and hyperactivity. Diagnosis of ADHD rose 42% from 2003–2004 to 2011–2012. In 2011, 3.5 million children were treated with drugs. Optimizing therapy can take a year, and may not be completely effective. A clinical trial is currently being conducted of a device/drug combination using the computer game Minecraft, to determine how certain activities affect executive function, working memory, and restraint in patients diagnosed with ADHD. The human subjects’ responses are being modeled using artificial neural networks (ANNs), an artificial intelligence method that can be utilized to interpret highly complex data. We propose using ANNs to optimize drug and Minecraft therapy for individual patients based on the initial NICHQ Vanderbilt assessment scores. We are applying ANNs in the development of computational models for executive function deficiencies in ADHD. These models will then be used to develop a therapeutic video game as a drug/device combination with stimulants for the treatment of ADHD symptoms in Fragile X Syndrome. As a first step towards the design of virtual subjects with executive function deficits, computational models of the core executive functions working memory and fluid intelligence were constructed. These models were combined to create healthy control and executive function-deficient virtual subjects, who performed a Time Management task simulation that required the use of their executive functions to complete. The preliminary working memory model utilized a convolutional neural network to identify handwritten digits from the MNIST dataset, and the fluid intelligence model utilized a basic recurrent neural network to produce sequences of integers in the range 1-9 that can be multiplied together to produce the number 12. A simplified Impulsivity function was also included in the virtual subject as a first step towards the future inclusion of the core executive function inhibition.

Overdose and addiction are two medical complications of cocaine abuse. To date, there is no FDA approved pharmacotherapy specific for cocaine abuse. Cocaine hydrolases (CocHs) have been extensively investigated for its potential in anti-cocaine therapy. Previous studies have demonstrated that CocHs efficiently hydrolyze cocaine to generate biologically inactive metabolites both in vivo and in vitro. However, it has not been studied whether there is gender difference in the therapy using CocHs. In addition, the effectiveness of CocHs is unknown for treating cocaine toxicity when alcohol is co-administered. The main purpose of this dissertation is to characterize and evaluate efficient CocHs for cocaine overdose and cocaine addiction treatment. In the first set of studies, the effectiveness of human serum albumin-fused CocH1 were studied in male and female rats. The pharmacokinetic profiles, as well as the pharmacodynamic effects of CocH1-HSA were compared in male and female rats. The obtained data clearly demonstrated that CocH1-HSA was equally effective in both genders. The second set of studies investigated the efficiency of Fc-fused CocH5 in reversing cocaine toxicity in rats receiving simultaneous administration of cocaine and alcohol. Results showed that CocH5-Fc rapidly hydrolyzed cocaine and cocaine’s toxic metabolites in rats, and demonstrated that CocH5-Fc was efficient in treating cocaine toxicity when alcohol was simultaneously administered. In later studies to investigate the effects of CocH5-Fc for the treatment of cocaine addiction, a mathematical model was developed and validated to predict the effects of CocH5-Fc on the disposition of cocaine in rat blood and brain. This model adequately described the effects of CocH5-Fc in accelerating the elimination of cocaine and its toxic metabolites in both rat blood and brain. In conclusion, the studies within the current dissertation demonstrate the clinical potential of CocHs for the treatment of both cocaine overdose and cocaine addiction.

Substance use disorders are serious health concerns in the United States. Furthermore, the National Survey on Drug Use and Health reports a continuous increase in substance use disorders in the United States during the last 10 years. However, there are not many effective pharmacotherapeutics available for substance use disorders. The current dissertation is focused on research aimed at discovering pharmacotherapeutics for substance use disorders. First part of dissertation focused on discovering methamphetamine (METH) use disorder therapeutics targeting specific mechanism of METH action on dopaminergic neurons. The second part of dissertation focused on opioids and cocaine use disorder therapeutics targeting rewarding pathway commonly activated by opioids and cocaine. With respect to METH, it induces release of dopamine (DA) in neuronal terminals by interacting with the vesicular monoamine transporter-2 (VMAT2) and DA transporter (DAT). VMAT2 inhibitors have been found by our research group to decrease METH-evoked DA release, METH-induced hyperlocomotion, and METH self-administration in rats. However, these VMAT2 inhibitors lacked selectivity and tolerance developed to these pharmacologic effects after repeated administration, thereby limiting their potential as pharmacotherapeutics for METH use disorders. In the current study, analogs from a novel scaffold were found to selectively inhibit VMAT2 and were evaluated using neurochemical and behavioral pharmacological approaches. R- and S-3-(4-methoxyphenyl)-N-(1-phenylpropan-2-yl)propan-1-amine (GZ-11610 and GZ-11608, respectively) exhibited 94- to 3450-fold selectivity for VMAT2 over human-ether-a-go-go (hERG) channel, DAT, serotonin transporter, and nicotinic acetylcholine receptors. GZ-11608 competitively and concentration-dependently inhibited METH-evoked DA release via VMAT2. Also, GZ-11610 (56-300 mg/kg, oral) and GZ-11608 (300 mg/kg, oral; 10-30 mg/kg, s.c.) reduced METH-induced hyperlocomotor activity in METH-sensitized rats. Furthermore, GZ-11608 (1-30 mg/kg, s.c.) inhibited METH self-administration, cue- and METH-induced reinstatement in a dose-dependent manner, and 30 mg/kg (s.c.), 10 mg/kg (s.c.), and 17 mg/kg (s.c.) produced significant effect, respectively. Importantly, the GZ-11608-induced decrease in METH self-administration was not surmounted by increasing the amount of METH available. GZ-11608 did not substitute for METH and did not serve as a reinforcer in rats self-administering METH and drug naïve rats, respectively. Thus, these VMAT2 inhibitors incorporating a new scaffold are novel leads for new pharmacotherapeutics to treat METH use disorders. Substances with high abuse potential including opioids and cocaine elevate extracellular DA concentration in the nucleus accumbens, and this mechanism has long been considered to underly substance-induced reward. DA in the nucleus accumbens originates from DA neuron cell bodies located in the ventral tegmental area in the midbrain. Interestingly, M5 muscarinic acetylcholine receptors (mAChRs) are proteins that are highly expressed on ventral tegmental area DA neurons. Also, studies investigating M5 mAChRs knockout mice showed reduced responding for cocaine in cocaine self-administration and decreased time spent in cocaine-paired and morphine-paired place preference studies. Pharmacological inhibition of M5 mAChRs function via microinfusing mAChR antagonists exhibiting no selectivity among M1-M5 mAChRs subtypes into the ventral tegmental area where expression of M5 mAChRs are dominant, reduced morphine-induced hyperlocomotion and cocaine seeking behaviors in rats. These studies support therapeutic potential of M5 mAChRs selectivity antagonists in opioids and cocaine use disorders. Thus, in the current study, affinity of a series of pethidine and quinuclidinyl N-phenylcarbamate analogs for M5 mAChRs was evaluated using in vitro and ex vivo neuropharmacological assays. Among the pethidine analogs, compound 6a showed the highest binding affinity at M5 (Ki = 0.38 µM), but also high affinity at M1 and M3 mAChRs (0.67 and 0.37 µM, respectively). Among the quinuclidinyl N-phenylcarbamate analogs, compound 13c exhibited the highest affinity at M5 (Ki = 1.8 nM), but also high affinity at M1, M2, M3 and M4 mAChRs (Ki = 1.6, 13, 2.6, 2.2 nM, respectively). Also, 13c acted as an agonist of mAChRs on oxotremorine-induced DA release from rat striatal slices. In addition, compound 13b was found exhibiting the highest selectivity (17-fold) at M3 over M2 mAChRs, suggesting potential of 13b as a chronic obstructive pulmonary disease therapeutics. Taken together, these novel analogs serve as leads for further discovery of subtype-selective M5 mAChR antagonists that may have potential as therapeutics for substance use disorders, as well as for chronic obstructive pulmonary disease.

Elderly patients with chronic obstructive pulmonary disease may be at increased risk of exacerbation due to physical and cognitive deficits that make proper inhaled medication adherence more difficult despite consistent medication access. This retrospective study utilized administrative medical and pharmacy claims data to examine the likelihood of having a COPD exacerbation requiring acute medical care by means of an emergency room visit or hospitalization in elderly patients receiving maintenance COPD medications from mail order and retail pharmacies. It was hypothesized that mail order patients would be more likely to experience exacerbations despite differences in medication access when compared to retail patients. The primary outcome of interest was exacerbation frequency expressed as the incidence density rate, and the secondary outcome was the proportion of days covered (PDC). The incidence rate ratio for acute exacerbations was not significantly different for mail order and retail groups, indicating patients using mail-order pharmacies were not significantly more likely to experience an exacerbation requiring acute medical care. Despite insignificant differences in incidence rates, mail order patients had significantly higher adherence rates.

Epilepsy affects 3.4 million patients in the USA and is characterized by recurring seizures. The blood-brain barrier is leaky in epilepsy and may contribute to seizure progression but the mechanisms which cause this leakage are not fully understood. We hypothesized that seizures trigger LOX- and COX-mediated blood-brain barrier leakage and that dual LOX/COX inhibition prevents barrier leakage in vivo. To test this hypothesis, we administered either the dual LOX/COX inhibitor licofelone or a combination of the 5-LOX inhibitor zileuton and the COX-2 inhibitor celecoxib to rats that experienced status epilepticus (SE). Serum and brain capillaries were isolated 48 hours after SE and serum S100β levels were measured and Texas Red™ leakage rates were determined. Dual inhibition of 5-LOX and COX prevented serum S100β elevations observed in SE rats in a dose-dependent manner with licofelone. Inhibition of 5-LOX and COX-2 with zileuton and celecoxib completely prevented serum S100β elevation. Texas Red™ leakage rates for SE rats were also reduced in a dose-depended manner with licofelone and reduced to control rates with zileuton and celecoxib. These data support our hypothesis that seizure-induced blood-brain barrier leakage is mediated by LOX and COX, and inhibition of these enzymes prevents barrier leakage.

Despite advances in healthcare, cardiovascular disease (CVD) remains the leading cause of death in the United States. Elevated levels of plasma cholesterol are highly predictive of CVD and stroke and are the principal driver of atherosclerosis. Unfortunately, current cholesterol lowering agents, such as statins, are not known to reverse atherosclerotic disease once it has been established. In preclinical models, agonists of nuclear receptor, LXR, have been shown to reduce and reverse atherosclerosis. Phytosterols are bioactive non-cholesterol sterols that act as LXR agonists and regulate cholesterol metabolism and transport. We hypothesize that stigmasterol would act as an LXR agonist and alter intestinal cholesterol secretion to promote cholesterol elimination. Mice were fed a control diet, or a diet supplemented with stigmasterol (0.3% w/w) or T0901317 (0.015% w/w), a known LXR agonist. In this experiment we analyzed the sterol content of bile, intestinal perfusate, plasma, and feces. Additionally, the liver and small intestine were analyzed for relative levels of transcripts known to be regulated by LXR. We observed that T0901317 robustly promoted cholesterol elimination and acted as a strong LXR agonist. Stigmasterol also promoted cholesterol elimination but did not alter LXR-dependent gene expression. Stigmasterol promoted transintestinal cholesterol secretion through an LXR-independent pathway.

Healthcare big data are a growing source of real-world data with which to identify and validate medications with repurposing potential. Previously, we developed a claims-based workflow to evaluate medications with potential to treat stimulant use disorders. In order to test the workflow, the framework was applied in the context of opioid use disorders (OUDs), for which there are medications with known efficacy. Using the Truven Marketscan Commercial Claims Database, a nested case-control analysis was conducted to determine the association between OUD medications (buprenorphine, naltrexone) and remission. Cases were defined as enrollees with a remission diagnosis and matched (1:4) to controls (individuals without remission) using incidence density sampling, with age group, sex, region, and index year as additional matching variables. After adjusting for behavioral health visits, polysubstance use disorders, and psychiatric disorders using conditional logistic regression, the odds of OUD medication exposure were 3.8 (99% confidence interval: 3.0 – 4.9) times higher in cases than controls. Evaluation of angiotensin converting enzyme inhibitors (e.g. lisinopril) as a negative control revealed no significant association between the medication and remission. This work demonstrates the feasibility of using administrative health claims data to evaluate the effectiveness of medications to treat substance use disorders.

Many pharmaceutical compounds being developed in recent years are poorly soluble in water. This has led to insufficient oral bioavailability of many compounds in vitro. The amorphous formulation is one of the promising techniques to increase the oral bioavailability of these poorly water-soluble compounds. However, an amorphous drug substance is inherently unstable because it is a high energy form. In order to increase the physical stability, the amorphous drug is often formulated with a suitable polymer to form an amorphous solid dispersion. Previous research has suggested that the formation of an intimately mixed drug-polymer mixture contributes to the stabilization of the amorphous drug compound. The goal of this research is to better understand the role of miscibility, molecular interactions and mobility on the physical stability of amorphous solid dispersions. Methods were developed to detect different degrees of miscibility on nanometer scale and to quantify the extent of hydrogen-bonding interactions between the drug and the polymer. Miscibility, hydrogen-bonding interactions and molecular mobility were correlated with physical stability during a six-month period using three model systems. Overall, this research provides molecular-level insights into many factors that govern the physical stability of amorphous solid dispersions which can lead to a more effective design of stable amorphous formulations.

The ABCG5 ABCG8 (G5G8) sterol transporter promotes cholesterol secretion into bile and opposes dietary sterol absorption in the small intestine. An emerging body of literature suggests that G5G8 links sterol flux to various risk factors for metabolic syndrome (MetS) and nonalcoholic fatty liver disease (NAFLD). Therapeutic approaches that accelerate G5G8 activity may augment reverse cholesterol transport (RCT) and provide beneficial effects in the prevention and treatment of cardiovascular and liver disease. Mice lacking leptin (ob/ob) or its receptor (db/db) are obese, insulin resistant in part due to the reduced levels of hepatic G5G8 and biliary cholesterol. The underlying mechanisms responsible for the reduced G5G8 protein expression in these mice may provide a clue to the drug development for this target. My studies show that neither acute leptin replacement nor liver-specific deletion of leptin receptor alters G5G8 abundance or biliary cholesterol. Similarly, hepatic vagotomy has no effect on G5G8 expression. Conversely, expression of the ER chaperone, GRP78, rescues G5G8 in db/db mice. Previous studies suggest an interdependent relationship between liver and intestine for cholesterol elimination. A combination therapy that increases G5G8-mediated biliary cholesterol secretion and simultaneously reduces intestinal absorption is likely to act additively in cholesterol elimination. My studies show that treatment with ursodiol (Urso) increases hepatic G5G8 protein and both biliary and fecal sterols in a dose-dependent manner. Ezetimibe (EZ), a potent inhibitor of intestinal cholesterol absorption, produces an additive and dose-dependent increase in fecal sterol excretion in the presence of Urso. However, the stimulatory effects of both Urso and Urso-EZ are not G5G8-dependent. Beyond increasing G5G8 protein expression and biliary cholesterol secretion, my studies also show that Urso stimulates ileal FGF15 expression in mice. Our data of the stimulated ileal FGF15 expression in LIRKO and reduced hepatic G5G8 protein levels in Atsb KO mice both indicate the previous unrecognized role of FGF15/19 in the regulation of G5G8 and its activity. Indeed, this is subsequently confirmed by our results from the direct test of recombinant human FGF19 on G5G8. Thus, FGF15/19 may provide an alternative strategy in drug development to target G5G8 activity and accelerate cholesterol elimination.

For patients afflicted with symptoms of anxiety and insomnia, benzodiazepines are generally a safe and effective short-term pharmacological treatment option. Although considered safer than other sedative-hypnotic medications, substantial concern exists regarding the addictive nature and abuse potential of benzodiazepines along with potentially inappropriate prescribing and utilization in clinically vulnerable populations. These medication misadventures can have a significant impact on public health. Examples of medication misadventures as they pertain to benzodiazepines include the prescribing and use in clinically vulnerable populations for whom they are contraindicated or their efficacy has not been evaluated, the development of tolerance or addiction, abuse of the medication, and the manifestation of negative health outcomes including cognitive impairment, withdrawal symptoms upon discontinuation, or the reoccurrence of a preexisting substance use disorder. In order to better understand medication misadventures associated with benzodiazepines retrospective analyses using populations extracted from large health claims databases are employed. To understand how benzodiazepine use may lead to adverse events causing patient harm, the risk of exacerbations in benzodiazepine users diagnosed with chronic obstructive pulmonary disease was estimated. The inherent risk of benzodiazepine addiction and abuse was estimated in an HIV-infected population, a population with a high prevalence of substance use disorders. This risk was estimated by first determining whether HIV-infected individuals are more likely to have any benzodiazepine use compared to their uninfected counterparts, and secondly, by examining the association between HIV-infection and potentially problematic benzodiazepine use. Finally, in an effort to mitigate unexpected and undesirable consequences to public health associated with the prescription drug abuse epidemic in the US, states have implemented prescription drug monitoring programs (PDMPs) to track the prescribing and dispensing of controlled substance medications. The effect of these programs on benzodiazepine dispensing is evaluated on a state and national level. Findings will provide healthcare professionals a better understanding regarding the risk of medication misadventures involving benzodiazepines when evaluating their appropriateness in patients with anxiety, depression, and insomnia. Additionally, policymakers will understand the implications of PDMPs on the dispensing of benzodiazepines as they become a more widely used tool to combat prescription drug abuse and diversion.