Chemicals and Drugs Commons^™

The Concise Guide To Pharmacology 2023/24: Enzymes, Stephen P. H. Alexander, Doriano Fabbro, Eamonn Kelly, Alistair Mathie, John A. Peters, Emma L. Veale, Jane F. Armstrong, Elena Faccenda, Simon D. Harding, James A. Davies, Stephanie Annett, Detlan Boison, Kathryn Elisa Burns, Carmen Dessauer, Jürg Gertsch, Nuala Ann Helsby, Angela A. Izzo, Rennolds Ostrom, Andreas Papapetropoulos, Nigel J. Pyne, Susan Pyne, Tracy Robson, Roland Seifert, Johannes-Peter Stasch, Csaba Szabo, Mario Van Der Stelt, Albert Van Der Vliet, Val Watts, Szu Shen Wong

Pharmacy Faculty Articles and Research

The Concise Guide to PHARMACOLOGY 2023/24 is the sixth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of approximately 1800 drug targets, and about 6000 interactions with about 3900 ligands. There is an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes almost 500 pages, the material presented is substantially reduced compared to information and links presented on the …

Promiscuous Enzymes For Residue-Specific Peptide And Protein Late-Stage Functionalization, Ashley K. Alexander, Sherif I. Elshahawi

Pharmacy Faculty Articles and Research

The late-stage functionalization of peptides and proteins holds significant promise for drug discovery and facilitates bioorthogonal chemistry. This selective functionalization leads to innovative advances in in vitro and in vivo biological research. It is a challenging endeavor to selectively target a certain amino acid or position in the presence of other residues containing reactive groups. Biocatalysis has emerged as a powerful tool for selective, efficient and economical modifications of molecules. Enzymes that have the ability to modify multiple complex substrates or selectively install nonnative handles have wide applications. Herein, we highlight enzymes with broad substrate tolerance that have been demonstrated …

Predicting Survival Of Nsclc Patients Treated With Immune Checkpoint Inhibitors: Impact And Timing Of Immune-Related Adverse Events And Prior Tyrosine Kinase Inhibitor Therapy, Michael R. Sayer, Isa Mambetsariev, Kun-Han Lu, Chi Wah Wong, Ashley Duche, Richard Beuttler, Jeremy Fricke, Rebecca Pharaon, Leonidas Arvanitis, Zahra Eftekhari, Arya Amini, Marianna Koczywas, Erminia Massarelli, Moom Rahman Roosan, Ravi Salgia

Pharmacy Faculty Articles and Research

Introduction: Immune checkpoint inhibitors (ICIs) produce a broad spectrum of immune-related adverse events (irAEs) affecting various organ systems. While ICIs are established as a therapeutic option in non-small cell lung cancer (NSCLC) treatment, most patients receiving ICI relapse. Additionally, the role of ICIs on survival in patients receiving prior targeted tyrosine kinase inhibitor (TKI) therapy has not been well-defined.

Objective: To investigate the impact of irAEs, the relative time of occurrence, and prior TKI therapy to predict clinical outcomes in NSCLC patients treated with ICIs.

Methods: A single center retrospective cohort study identified 354 adult patients with NSCLC receiving ICI …

Editorial: Adenylyl Cyclase Isoforms As Potential Drug Targets, Tarsis F. Brust, Rennolds S. Ostrom, Val J. Watts

Pharmacy Faculty Articles and Research

Editorial on the Research Topic Adenylyl cyclase isoforms as potential drug targets

Effects Of Chronic Cirrhosis Induced By Intraperitoneal Thioacetamide Injection On The Protein Content And Michaelis–Menten Kinetics Of Cytochrome P450 Enzymes In The Rat Liver Microsomes, Devaraj Venkatapura Chandrashekar, Barent N. Dubois, Mamunur Rashid, Reza Mehvar

Pharmacy Faculty Articles and Research

Chronic intraperitoneal injection of thioacetamide (TAA) in rats has been used as an animal model of human cirrhosis to study the effects of the disease on drug metabolism. However, TAA inhibits P450 enzymes directly and independently of cirrhosis. We investigated the effects of chronic cirrhosis in rats, induced by 10 weeks of intraperitoneal TAA, on the P450 enzymes after a 10-day washout period to eliminate TAA. Liver histology and serum biomarkers of hepatic function confirmed cirrhosis in all animals. Microsomal total P450 content, P450 reductase activity and ethoxycoumarin O-deethylase activity, a general marker of P450 activity, were significantly reduced by …

Synthesis And Evaluation Of Anti-Hiv Activity Of Mono- And Di-Substituted Phosphonamidate Conjugates Of Tenofovir, Aaminat Qureshi, Louise A. Ouattara, Naglaa Salem El-Sayed, Amita Verma, Gustavo F. Doncel, Muhammad Iqbal Choudhary, Hina Siddiqui, Keykavous Parang

Pharmacy Faculty Articles and Research

The activity of nucleoside and nucleotide analogs as antiviral agents requires phosphorylation by endogenous enzymes. Phosphate-substituted analogs have low bioavailability due to the presence of ionizable negatively-charged groups. To circumvent these limitations, several prodrug approaches have been proposed. Herein, we hypothesized that the conjugation or combination of the lipophilic amide bond with nucleotide-based tenofovir (TFV) (1) could improve the anti-HIV activity. During the current study, the hydroxyl group of phosphonates in TFV was conjugated with the amino group of L-alanine, L-leucine, L-valine, and glycine amino acids and other long fatty ester hydrocarbon chains to synthesize 43 derivatives. Several …

Interactions Among Endothelial Nitric Oxide Synthase, Cardiovascular System, And Nociception During Physiological And Pathophysiological States, Niribili Sarmah, Andromeda M. Nauli, Ahmmed Ally, Surya M. Nauli

Pharmacy Faculty Articles and Research

Nitric oxide synthase (NOS) plays important roles within the cardiovascular system in physiological states as well as in pathophysiologic and specific cardiovascular (CV) disease states, such as hypertension (HTN), arteriosclerosis, and cerebrovascular accidents. This review discusses the roles of the endothelial NOS (eNOS) and its effect on cardiovascular responses that are induced by nociceptive stimuli. The roles of eNOS enzyme in modulating CV functions while experiencing pain will be discussed. Nociception, otherwise known as the subjective experience of pain through sensory receptors, termed “nociceptors”, can be stimulated by various external or internal stimuli. In turn, events of various cascade pathways …

Late-Stage Chemoenzymatic Installation Of Hydroxy-Bearing Allyl Moiety On The Indole Ring Of Tryptophan-Containing Peptides, Nagaraju Mupparapu, Lauren Brewster, Katrina F. Ostrom, Sherif I. Elshahawi

Pharmacy Faculty Articles and Research

The late-stage functionalization of indole- and tryptophan-containing compounds with reactive moieties facilitates downstream diversification and leads to changes in their biological properties. Here, the synthesis of two hydroxy-bearing allyl pyrophosphates is described. A chemoenzymatic method is demonstrated which uses a promiscuous indole prenyltransferase enzyme to install a dual reactive hydroxy-bearing allyl moiety directly on the indole ring of tryptophan-containing peptides. This is the first report of late-stage indole modifications with this reactive group.

Endothelial Nitric Oxide Synthase (Enos) And The Cardiovascular System: In Physiology And In Disease States, N Tran, T Garcia, M Aniqa, S Ali, A Ally, Surya M. Nauli

Pharmacy Faculty Articles and Research

Endothelial nitric oxide synthase (eNOS) plays a critical role in regulating and maintaining a healthy cardiovascular system. The importance of eNOS can be emphasized from the genetic polymorphisms of the eNOS gene, uncoupling of eNOS dimerization, and its numerous signaling regulations. The activity of eNOS on the cardiac myocytes, vasculature, and the central nervous system are discussed. The effects of eNOS on the sympathetic autonomic nervous system (SANS) and the parasympathetic autonomic nervous system (PANS), both of which profoundly influence the cardiovascular system, will be elaborated. The relationship between the eNOS protein with cardiovascular autonomic reflexes such as the baroreflex …

Physiological Roles Of Mammalian Transmembrane Adenylyl Cyclase Isoforms, Katrina F. Ostrom, Justin E. Lavigne, Tarsis F. Brust, Roland Seifert, Carmen Dessauer, Val J. Watts, Rennolds S. Ostrom

Pharmacy Faculty Articles and Research

Adenylyl cyclases (ACs) catalyze the conversion of ATP to the ubiquitous second messenger cAMP. Mammals possess nine isoforms of transmembrane ACs, dubbed AC1-9, that serve as major effector enzymes of G protein-coupled receptors. The transmembrane ACs display varying expression patterns across tissues, giving potential for them having a wide array of physiologic roles. Cells express multiple AC isoforms, implying that ACs have redundant functions. Furthermore, all transmembrane ACs are activated by Gα_s so it was long assumed that all ACs are activated by Gα_s-coupled GPCRs. AC isoforms partition to different microdomains of the plasma membrane and form …

The Concise Guide To Pharmacology 2021/22: Enzymes, Stephen Ph Alexander, Doriano Fabbro, Eamonn Kelly, Alistair Mathie, John A. Peters, Emma L. Veale, Jane F. Armstrong, Elena Faccenda, Simon D. Harding, Adam J. Pawson, Christopher Southan, James A. Davies, Detlan Boison, Kathryn Elisa Burns, Carmen Dessauer, Jürg Gertsch, Nuala Ann Helsby, Angela A. Izzo, Doris Koesling, Rennolds Ostrom, Nigel J. Pyne, Susan Pyne, Michael Russwurm, Roland Seifert, Johannes-Peter Stasch, Mario Van Der Stelt, Albert Van Der Vliet, Val Watts, Szu Shen Wong

Pharmacy Faculty Articles and Research

The Concise Guide to PHARMACOLOGY 2021/22 is the fifth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of nearly 1900 human drug targets with an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes over 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record …

Uplc-Ms/Ms Analysis Of The Michaelis-Menten Kinetics Of Cyp3a-Mediated Midazolam 1′- And 4-Hydroxylation In Rat Brain Microsomes, Devaraj Venkatapura Chandrashekar, Barent Dubois, Reza Mehvar

Pharmacy Faculty Articles and Research

Midazolam (MDZ) is a short-acting benzodiazepine with rapid onset of action, which is metabolized by CYP3A isoenzymes to two hydroxylated metabolites, 1′-hydroxymidazolam and 4-hydroxymidazolam. The drug is also commonly used as a marker of CYP3A activity in the liver microsomes. However, the kinetics of CYP3A-mediated hydroxylation of MDZ in the brain, which contains much lower CYP content than the liver, have not been reported. In this study, UPLC-MS/MS and metabolic incubation methods were developed and validated for simultaneous measurement of low concentrations of both hydroxylated metabolites of MDZ in brain microsomes. Different concentrations of MDZ (1–500 µM) were incubated with …

Differential Effect Of Proinflammatory Cytokines On Corneal And Conjunctival Epithelial Cell Mucins And Glycocalyx, Kiumars Shamloo, Priya Mistry, Ashley Barbarino, Christopher Ross, Vishal Jhanji

Pharmacy Faculty Articles and Research

Purpose: Ocular surface mucins and glycocalyx are critical for providing ocular hydration as well lubrication and repelling pathogens or allergens. Elevated levels of tear proinflammatory cytokines in dry eye may have detrimental effect on mucins and glycocalyx. The present study tested the effect of proinflammatory cytokines IL-6, TNF-α, and IFN-γ on membrane-tethered mucins expression, glycocalyx, and viability of ocular surface epithelial cells.

Methods: Stratified cultures of human corneal and conjunctival epithelial cells were exposed to different concentrations of IL-6, TNF-α, and IFN-γ for 24 hours. The mucins gene and protein expressions were quantified by real-time polymerase chain reaction …

Kinetics Of Dextromethorphan-O-Demethylase Activity And Distribution Of Cyp2d In Four Commonly-Used Subcellular Fractions Of Rat Brain, Barent N. Dubois, Farideh Amirrad, Reza Mehvar

Pharmacy Faculty Articles and Research

The purpose of this study was to compare the enzymatic kinetics and distribution of cytochrome P450 2D (CYP2D) among different rat brain subcellular fractions.

Rat brains were used to prepare total membrane, crude mitochondrial, purified mitochondrial, and microsomal fractions, in addition to total homogenate. Michaelis–Menten kinetics of the brain CYP2D activity was estimated based on the conversion of dextromethorphan (DXM) to dextrorphan using UPLC-MS/MS. Protein levels of CYP2D and subcellular markers were determined by Western blot.

Microsomal CYP2D exhibited high affinity and low capacity, compared with the mitochondrial CYP2D that had a much lower (∼50-fold) affinity but a higher (∼six-fold) …

Correcting Glucose-6-Phosphate Dehydrogenase Deficiency With A Small-Molecule Activator, Sunhee Hwang, Karen Mruk, Simin Rahighi, Andrew G. Raub, Che-Hong Chen, Lisa E. Dorn, Naoki Horikoshi, Soichi Wakatsuki, James K. Chen, Daria Mochly-Rosen

Pharmacy Faculty Articles and Research

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, one of the most common human genetic enzymopathies, is caused by over 160 different point mutations and contributes to the severity of many acute and chronic diseases associated with oxidative stress, including hemolytic anemia and bilirubin-induced neurological damage particularly in newborns. As no medications are available to treat G6PD deficiency, here we seek to identify a small molecule that corrects it. Crystallographic study and mutagenesis analysis identify the structural and functional defect of one common mutant (Canton, R459L). Using high-throughput screening, we subsequently identify AG1, a small molecule that increases the activity of the wild-type, the …

“Do We Know Jack” About Jak? A Closer Look At Jak/Stat Signaling Pathway, Emira Bousoik, Hamidreza Montazeri Aliabadi

Pharmacy Faculty Articles and Research

Janus tyrosine kinase (JAK) family of proteins have been identified as crucial proteins in signal transduction initiated by a wide range of membrane receptors. Among the proteins in this family JAK2 has been associated with important downstream proteins, including signal transducers and activators of transcription (STATs), which in turn regulate the expression of a variety of proteins involved in induction or prevention of apoptosis. Therefore, the JAK/STAT signaling axis plays a major role in the proliferation and survival of different cancer cells, and may even be involved in resistance mechanisms against molecularly targeted drugs. Despite extensive research focused on the …

Pde8 Is Expressed In Human Airway Smooth Muscle And Selectively Regulates Camp Signaling By Β 2 Ar-Ac6, Timothy B. Johnstone, Kaitlyn H. Smith, Cynthia J. Koziol-White, Fengying Li, Austin G. Kazarian, Maia L. Corpuz, Maya Shumyachter, Frederick J. Ehlert, Bianca E. Himes, Reynold A. Pannettieri Jr., Rennolds S. Ostrom

Pharmacy Faculty Articles and Research

Two cAMP signaling compartments centering around adenylyl cyclase (AC) exist in human airway smooth muscle (HASM) cells, one containing ß2AR-AC6 and another containing E prostanoid receptors (EPR)-AC2. We hypothesized that different phosphodiesterase (PDE) isozymes selectively regulate cAMP signaling in each compartment. According to RNA-seq data, 18 of 24 PDE genes were expressed in primary HASM cells derived from age- and gender-matched donors with and without asthma. PDE8A was the third most abundant of the cAMP-degrading PDE genes, after PDE4A and PDE1A. Knockdown of PDE8A using shRNA evoked 2-fold greater cAMP responses to 1 DM forskolin in the presence of IBMX. …

Design, Synthesis, And Evaluation Of Dasatinib-Amino Acid And Dasatinib-Fatty Acid Conjugates As Protein Tyrosine Kinase Inhibitors, Rakesh Tiwari, Alex Brown, Neda Sadeghiani, Amir Nasrolahi Shirazi, Jared Bolton, Amanda Tse, Gennady M. Verkhivker, Keykavous Parang, Gongqin Sun

Pharmacy Faculty Articles and Research

Derivatives of dasatinib were synthesized via esterification with 25 carboxylic acids including amino acids and fatty acids by extending the inhibitor to interact with more diverse sites and to improve specificity. Dasatinib-L-arginine derivative (Das-R, 7) was the most potent of the inhibitors tested with IC50 values of 4.4 nM, <0.25 nM, and <0.45 nM against Csk, Src, and Abl kinases, respectively. The highest selectivity ratio obtained in our study, 91.4 Csk/Src belonged to compound 18 (Das-C10) with an IC50 of 3.2 μM for Csk compared to 35 nM for Src. Furthermore, many compounds displayed increased selectivity toward Src, as compared with Abl. Compounds 15 (Das-E) and 13 (Das-C) demonstrated the largest gains (10.2 and 10.3 Abl/Src IC50 ratios). Das-R (IC50 = 2.06 μM) was significantly more potent than Das (IC50 = 26.3 μM) against Panc-1 cells while they both showed an IC50 < 51.2 pM against BV-173 and K562 cells. Molecular modeling and binding free energy simulations revealed a good agreement with the experimental results and rationalized differences in selectivity of the studied compounds. Integration of experimental and computational approaches in the design and biochemical screening of dasatinib derivatives facilitated rational engineering and diversification of dasatinib scaffold, providing useful insights into mechanisms of kinase selectivity.

Selective Binding Of Airapl Tandem Uims To Lys48-Linked Tri-Ubiquitin Chains, Simin Rahighi, Ilauna Braunstein, Nicola Ternette, Benedikt Kessler, Masato Kawasaki, Ryuichi Kato, Tsutomu Matsui, Ariel Stanhill, Soichi Wakatsuki

Pharmacy Faculty Articles and Research

Lys48-linked ubiquitin chains act as the main targeting signals for protein degradation by the proteasome. Here we report selective binding of AIRAPL, a protein that associates with the proteasome upon exposure to arsenite, to Lys48-linked tri-ubiquitin chains. AIRAPL comprises two ubiquitin-interacting motifs in tandem (tUIMs) that are linked through a flexible inter-UIM region. In the complex crystal structure UIM1 binds the proximal ubiquitin, whereas UIM2 (the double-sided UIM) binds non-symmetrically to the middle and distal ubiquitin moieties on either side of the helix. Specificity of AIRAPL for Lys48-linked ubiquitin chains is determined by UIM2, and the flexible inter-UIM linker increases …

Mechanism Underlying Ikk Activation Mediated By The Linear Ubiquitin Chain Assembly Complex (Lubac), Hiroaki Fujita, Simin Rahighi, Mariko Akita, Ryuichi Kato, Yoshiteru Sasaki, Soichi Wakatsuki, Kazuhiro Iwai

Pharmacy Faculty Articles and Research

The linear ubiquitin chain assembly complex (LUBAC) ligase, consisting of HOIL-1L, HOIP, and SHARPIN, specifically generates linear polyubiquitin chains. LUBAC-mediated linear polyubiquitination has been implicated in NF-κB activation. NEMO, a component of the IκB kinase (IKK) complex, is a substrate of LUBAC, but the precise molecular mechanism underlying linear chain-mediated NF-κB activation has not been fully elucidated. Here, we demonstrate that linearly polyubiquitinated NEMO activates IKK more potently than unanchored linear chains. In mutational analyses based on the crystal structure of the complex between the HOIP NZF1 and NEMO CC2-LZ domains, which are involved in the HOIP-NEMO interaction, NEMO mutations …

Synthesis And Evaluation Of C-Src Kinase Inhibitory Activity Of Pyridin-2(1h)-One Derivatives, Karam Chand, Suchita Prasad, Rakesh Tiwari, Amir Nasrolahi Shirazi, Sumit Kumar, Keykavous Parang, Sunil K. Sharma

Pharmacy Faculty Articles and Research

Src kinase, a prototype member of the Src family of kinases (SFKs), is over-expressed in various human tumors, and has become a target for anticancer drug design. In this perspective, a series of eighteen 2-pyridone derivatives were synthesized and evaluated for their c-Src kinase inhibitory activity. Among them, eight compounds exhibited c-Src kinase inhibitory activity with IC50 value of less than 25 mu M. Compound 1-[2-(dimethylamino)ethyl]-5-(2-hydroxy-4-methoxybenzoyl)pyridin-2(1H)-one (36) exhibited the highest c-Src kinase inhibition with an IC50 value of 12.5 mu M. Furthermore, the kinase inhibitory activity of compound 36 was studied against EGFR, MAPK and PDK, however no significant activity …

Synthesis Of Pyrazolo[3,4-D]Pyrimidine Derivatives And Evaluation Of Their Src Kinase Inhibitory Activities, Anil Kumar, Guofeng Ye, Xianfeng Gu, Yuehao Wang, Gongqin Sun, Keykavous Parang

Pharmacy Faculty Articles and Research

A series of pyrazolo[3,4-d]pyrimidine derivatives was synthesized and evaluated for the Src kinase inhibitory activities. Compound 6e and 10c exhibited inhibition of Src kinase with an IC50 value of 5.6 and 5.1 μM, respectively. Hydroxamate derivative 15a was found to be a metal-mediated inhibitor for human Csk with an IC50 value of 2.0 μM showing 56-fold selectivity over Src kinase inhibition.

Selectivity Of The Ubiquitin-Binding Modules, Simin Rahighi, Ivan Dikic

Pharmacy Faculty Articles and Research

Ubiquitin-binding modules are constituents of cellular proteins that mediate the effects of ubiquitylation by making transient, non-covalent interactions with ubiquitin molecules. While some ubiquitin- binding modules bind single ubiquitin moieties, others are selective for specific ubiquitin chains of different linkage types and lengths. In recent years, functions of ubiquitin chains that are polymerized through their Lys or N-terminal Met (i.e. linear chains) residues have been linked to a variety of cellular processes. Selectivity of ubiquitin-binding modules for different ubiquitin chain types appears as a key to the distinct regulatory consequences during protein quality control pathways, receptor endocytosis, gene transcription, signaling …

Substituted Coumarin Derivatives: Synthesis And Evaluation Of Antiproliferative And Src Kinase Inhibitory Activities, Abha Kathuria, Sarah Jalal, Rakesh Tiwari, Amir Nasrolahi Shirazi, Shilpi Gupta, Shiv Kumar, Keykavous Parang, Sunil K. Sharma

Pharmacy Faculty Articles and Research

Six classes of coumarin derivatives (i.e. 3-alkyl-4-methylcoumarins, pyranocoumarins, coumarin carboxamides, quaternary ammonium coumarins, 7-aminocoumarins, and 4-aminocoumarins) were synthesized and evaluated for inhibition of cell proliferation of colon adenocarcinoma (HT-29), breast carcinoma (MDA-MB-468 or MCF-7), and human ovarian adenocarcinoma (SK-OV-3) cells. C-3-Alkyl substituted analogs of 4-methylcoumarins and pyranocoumarins, 5 and 6, inhibited the cell proliferation of MDA-MB-468 and SK-OV-3 cells by 53-74%, while 3-decyl substituted pyranocoumarin 10 and triethyl substituted quaternary ammonium coumarin derivative 29 inhibited the cell proliferation of HT-29 and SK-OV-3 cells by 63-72% at a concentration of 50 μM. Among all the compounds studied, C-3 decyl substituted quaternary …

Enzymatic Processing Of Amelogenin During Continuous Crystallization Of Apatite, Vuk Uskoković, M.-K. Kim, W. Li, S. Habelitz

Pharmacy Faculty Articles and Research

Dental enamel forms through a protein-controlled mineralization and enzymatic degradation with a nanoscale precision that new engineering technologies may be able to mimic. Recombinant fulllength human amelogenin (rH174) and a matrix-metalloprotease (MMP-20) were employed in a pHstat titration system that enabled a continuous supply of calcium and phosphate ions over several days, mimicking the initial stages of matrix processing and crystallization in enamel in-vitro. Effects on the self-assembly and crystal growth from a saturated aqueous solution containing 0.4 mg/ml rH174 and MMP-20 with the weight ratio of 1:1000 with respect to rH174 were investigated. A transition from nanospheres to fibrous …

Novel Approaches For Designing 5'-O-Ester Prodrugs Of 3'-Azido-2'3'-Dideoxythymidine (Azt), Keykavous Parang, Leonard I. Wiebe, Edward E. Knaus

Pharmacy Faculty Articles and Research

3'-Azido-2'3'-dideoxythymidine (AZT, 1, zidovudine, RetrovirTM) is used to treat patients with human immunodeficiency virus (HIV) infection. AZT, after conversion to AZT-5'-triphosphate (AZT-TP) by cellular enzymes, inhibits HIV-reverse transcriptase (HIV-RT). The major clinical limitations of AZT are due to clinical toxicities that include bone marrow suppression, hepatic abnormalities and myopathy, absolute dependence on host cell kinase-mediated activation which leads to low activity, limited brain uptake, a sort half-life of about one hour in plasma that dictates frequent administration to maintain therapeutic drug levels, low potential for metabolic activation and/or high susceptibility to catabolism, and the rapid development of resistance by HIV-1. …