CHE316 3/25

"Describe the process of fragment-based screening in drug discovery."

"Fragment-based screening involves screening hundreds of thousands of small compounds (fragments) to identify those that can bind to a protein's active or allosteric site. The goal is to increase the likelihood of binding by using smaller molecules that have fewer interactions and lower affinity, which can then be linked together to form lead compounds with better binding affinity."

"Explain the significance of IRAK inhibitors in inflammation."

"IRAK inhibitors target the IRAK kinase, which plays a role in inflammation. By inhibiting this kinase, the compounds can potentially serve as anti-inflammatory agents. A clinical candidate was developed from hits identified through fragment screening, although initial binding affinity was too high, indicating a need for further optimization."

"How does the concept of lead compounds relate to fragment-based screening?"

"Lead compounds are developed by linking small fragments identified during fragment-based screening. The aim is to create larger compounds that exhibit good binding affinity and activity at the target site, enhancing the chances of successful drug development."

"Define the four key processes of ADME in drug design."

"ADME stands for Absorption, Distribution, Metabolism, and Excretion. These processes are crucial in drug design as they determine how a drug is absorbed into the body, how it is distributed throughout the body, how it is metabolized or transformed, and how it is excreted from the body."

"Do poor absorption characteristics affect drug development?"

"Yes, poor absorption characteristics can significantly hinder drug development. Factors such as high molecular weight, excessive hydrogen-bond donors or acceptors, and unfavorable partition coefficients can indicate that a molecule is unlikely to effectively cross biological membranes."

"Explain the importance of the partition coefficient in drug design."

"The partition coefficient (P), measured as log(P), is a measure of a drug's polarity and its ability to cross membranes. A log(P) value greater than 5 suggests poor absorption, while an ideal range is between 1.1 and 1.8. This coefficient is determined by measuring the concentration of a drug in n-octanol versus water."

"How can metabolic activity affect drug safety?"

"Metabolic activity can alter a drug within the human body, potentially converting it into a toxic product. This transformation is a significant concern in drug safety, as it can lead to adverse effects and limit the drug's therapeutic use."

"Describe the role of docking in the drug development process."

"Docking is used to predict the binding affinity of a fragment to a target protein by calculating the change in Gibbs free energy (delta G). This helps in assessing how well a fragment may bind to the target and guides the optimization of drug candidates."

"What factors indicate that a molecule may have poor absorption?"

"Factors indicating poor absorption include a molecular weight greater than 500 Da, more than 5 hydrogen-bond donors, more than 10 hydrogen-bond acceptors, and a partition coefficient (log(P)) greater than 5."

"Explain the concept of linking fragments in drug design."

"Linking fragments involves combining small drug-like molecules that have shown potential binding to a target protein. This process aims to create larger, more effective compounds that maintain or enhance binding affinity and biological activity."

"Describe the significance of Lipinski's rules in drug development."

"Lipinski's rules help to determine the bioavailability of compounds, indicating their potential effectiveness as drugs."

"Explain the role of blood proteins in drug distribution."

"Compounds that do not dissolve readily in blood bind to blood proteins, such as albumin, which affects their distribution in the body."

"How does P-glycoprotein affect drug transport in cells?"

"P-glycoprotein is an active transporter that exports drugs from cells using ATP, recognizing drug-like compounds that do not belong in the cell."

"Define the blood-brain barrier and its importance in pharmacology."

"The blood-brain barrier consists of closely spaced, fairly impermeable cells that allow gases and nutrients to cross while blocking many drugs, making it difficult for drugs to reach the brain and CNS."

"What happens if a drug is too polar in relation to the blood-brain barrier?"

"If a drug is too polar, it may not cross the blood-brain barrier effectively, limiting its therapeutic effects in the brain."

"Do you want a drug to be a P-glycoprotein substrate? Why or why not?"

"No, you do not want a drug to be a P-glycoprotein substrate because it will be actively exported out of cells, reducing its effectiveness."

"Explain the concept of the boiled egg plot in pharmacology."

"The boiled egg plot visually represents the intestinal absorptivity of compounds, with the white area indicating high absorptivity."

"How do compounds distribute to different tissues in the body?"

"Compounds can be distributed to various fluids or tissues (compartments) based on their solubility and binding properties."

"What is the impact of a drug's polarity on its bioavailability?"

"A drug's polarity affects its ability to dissolve in blood and cross biological barriers, influencing its bioavailability and therapeutic effectiveness."

"Describe the significance of the color yellow in relation to drug properties."

"Yellow indicates a high likelihood for a drug to cross the blood-brain barrier (BBB)."

"Explain the process of drug metabolism."

"Drugs are metabolized primarily through oxidation and conjugation reactions."

"How do cytochrome P450 enzymes contribute to drug metabolism?"

"Cytochrome P450 enzymes catalyze oxidation reactions, which are crucial for drug metabolism."

"What are the potential consequences of inhibiting cytochrome P450 enzymes?"

"Inhibition can indicate toxicity or cause severe toxicity when combined with other drugs."

"Define conjugation reactions in drug metabolism."

"Conjugation reactions involve the addition of substances like glucuronic acid, sulfate, or amino acids to increase drug solubility and aid in excretion."

"Explain the role of glutathione reductase in drug metabolism."

"Glutathione reductase recycles glutathione via the pentose phosphate pathway, which is important for detoxification."

"How does acetaminophen undergo metabolism in the liver?"

"Acetaminophen is first oxidized by cytochrome P450, converting its phenolic group to a ketone, and then glutathione is added ortho to the ketone."

"What can happen if the liver does not have sufficient glutathione when processing acetaminophen?"

"Insufficient glutathione can lead to necrotic cell death in the liver."

"Describe the effect of large doses of acetaminophen on liver glutathione levels."

"Large doses can deplete liver glutathione, increasing the risk of toxicity."

"How can toxicity impact drug effectiveness?"

"Toxicity can limit the effectiveness of drugs, potentially leading to adverse effects."

"Describe the consequences of drug toxicity."

"Drug toxicity can occur if a drug is overly effective or interacts with proteins other than its intended target."

"Explain how drug transformations can lead to toxicity."

"Drug transformations can sometimes produce toxic metabolites, with acetaminophen being a common example."

"Define the therapeutic index in pharmacology."

"The therapeutic index is the ratio of the concentration of a drug required to kill 50% of test organisms (LD50) to the effective concentration (EC50)."

"How does drug excretion occur in the body?"

"Excretion can occur through the kidneys, or drugs can be concentrated in the gallbladder and excreted into the intestine."

"What happens to drugs and metabolites in the intestine?"

"In the intestine, drugs and metabolites can be excreted through stool, reabsorbed into the bloodstream, or further degraded by digestive enzymes."

"Explain the process of enterohepatic cycling."

"Enterohepatic cycling is the recycling of compounds from the bloodstream into the intestine and back, which can significantly slow the excretion rate."

"Define the half-life of a drug."

"The half-life of a drug is the time required to eliminate 50% of the compound from the body."

"How does knowledge of drug target structure aid in drug design?"

"Understanding the structure of a drug target allows for structure-based drug design, leading to more effective drug development."

"Describe the synthesis of HIV protease inhibitors."

"HIV protease inhibitors were synthesized using structure-based drug design and subsequently improved through compound optimization."

"What role does structure-based drug design play in synthesizing COX2 inhibitors?"

"Structure-based drug design was utilized to create inhibitors of cyclooxygenase 2 (COX2), which is crucial in the inflammatory immune response."

"Explain the purpose of fragment screening in drug design."

"Fragment screening provides valuable information that guides the drug design process."

"How was the initial design of an HIV protease inhibitor approached?"

"The initial design combined parts of one compound with good inhibition activity but poor solubility with another compound that had better solubility."

"What is compound optimization in drug development?"

"Compound optimization involves analyzing the structure-activity relationship (SAR) to improve drug efficacy and bioavailability."

"Describe the characteristics of the antiviral PF-00835231 against SARS-CoV-2."

"PF-00835231 is structurally similar to a peptide that binds within SARS and is rich in hydrogen bond donors, which affects its pharmacokinetics."

"Explain the significance of hydrogen bond donors in PF-00835231."

"PF-00835231 has five hydrogen bond donors, contributing to its polar surface area and affecting its absorption in the gut."

"What are Lepinski’s rules and how does PF-00835231 relate to them?"

"Lepinski’s rules are guidelines for drug-like properties, and PF-00835231 is considered a strong violator of these rules due to its peptide-like structure."