Pharmacology

• Drug/Ligand Binding:

  • Definition: Interaction between a drug (ligand) and its specific biological target, such as a protein (receptor, enzyme, etc.).
  • Mechanism: Typically reversible and involves non-covalent interactions like hydrogen bonds, ionic bonds, van der Waals forces, and hydrophobic interactions.
• Binding Affinity:

  • Definition: A measure of the strength of the interaction between a drug and its target.
  • Implication: High affinity means the drug binds tightly and effectively at lower concentrations, whereas low affinity requires higher concentrations for effective binding
• The ligand is a chemical messenger released by 1 cell to signal itself or a different cell. The binding results in a cellular effect, which manifests as any number of changes in that cell, including altering gene transcription or translation or changing cell morphology.
• Genetic Variability, Ligand Binding, and Personalized Healthcare

  Genetic Variability:

  • Impact: Variations in genes among individuals can affect the structure and function of proteins, including drug targets (e.g., receptors, enzymes).
  • Outcome: This can alter how well a drug binds to its target.

  Impact on Personalized Healthcare:

  • Variability in Response: Genetic differences can lead to variability in drug efficacy and safety among individuals.
  • Personalized Treatments: Personalized healthcare uses genetic information to tailor drug treatments for better efficacy and reduced adverse effects.
• Importance of Molecular Structure, Molecular Target, and Target Tissue Characteristics.

  Molecular Structure:

  • Importance: Determines the specific interactions between a drug and its target.
  • Outcome: Influences binding affinity and specificity.
• Importance of Molecular Structure, Molecular Target, and Target Tissue Characteristics.

  Molecular Target:

  • Nature: The type of drug target (e.g., receptor, enzyme) affects how the drug will work.
  • Mechanism of Action: Different targets have different mechanisms of action.
• Importance of Molecular Structure, Molecular Target, and Target Tissue Characteristics.

  Target Tissue Characteristics:

  • Distribution and Accessibility: The distribution and accessibility of the drug to the target tissue are crucial.
  • Factors: Blood flow, tissue permeability, and presence of specific receptors impact the drug’s effectiveness.
• Common Classes of Protein Targets for Drugs.

  Enzymes:

  • Function: Catalyze biochemical reactions.
  • Drug Action: Drugs can inhibit or activate enzymes to alter metabolic pathways.
• Common Classes of Protein Targets for Drugs.

  Carrier Molecules:

  • Function: Transport substances across cell membranes.
  • Drug Action: Drugs can inhibit these carriers to affect cellular uptake of substances.
• Common Classes of Protein Targets for Drugs.

  Ion Channels:

  • Function: Allow ions to pass through cell membranes.
  • Drug Action: Drugs can modulate these channels to alter electrical activity in cells.
• Common Classes of Protein Targets for Drugs.

  Receptors:

  • Function: Bind signaling molecules (ligands) and initiate cellular responses.
  • Drug Action: Drugs can act as agonists (activating receptors) or antagonists (blocking receptors).
• Drug-Specificity:

  • Definition: The ability of a drug to selectively bind to its intended target without affecting other proteins or pathways.
  • Benefit: High specificity reduces the risk of side effects.
• Non-Specific Drug Effects:

  • Definition: Occur when a drug affects multiple targets, leading to unintended actions and potential side effects.
  • Challenge: Non-specificity can complicate the therapeutic profile of a drug.
• Absorption:

  • Definition: The process by which a drug enters the bloodstream from its site of administration.
• Distribution:

  • Definition: The dispersion of a drug throughout the body’s fluids and tissues.
• Metabolism:

  • Definition: The chemical alteration of a drug by the body, primarily in the liver.
  • Purpose: Often involves converting the drug into more water-soluble compounds for easier elimination.
• Elimination:

  • Definition: The removal of the drug and its metabolites from the body.
  • Routes: Mainly through the kidneys (urine) or the liver (bile).
• Phase One Metabolism:

  • Reactions: Involves chemical reactions such as oxidation, reduction, and hydrolysis.
  • Enzymes: Often catalyzed by enzymes like cytochrome P450.
  • Purpose: Introduce or expose functional groups on the drug molecule.
• Phase Two Metabolism:

  • Reactions: Involves conjugation reactions where the drug or its Phase One metabolites are linked with endogenous molecules (e.g., glucuronic acid, sulfate).
  • Purpose: Forms more water-soluble compounds for excretion.
• First-Pass Metabolism:

  • Definition: Refers to the initial metabolism of a drug in the liver and intestines immediately after oral administration.
  • Impact: Can significantly reduce the bioavailability of a drug, affecting its efficacy and dosing.
• Routes for Drug Administration:

  • Oral
  • Intravenous (IV)
  • Intramuscular (IM)
  • Subcutaneous (SC)
  • Inhalation
  • Topical
  • Sublingual/Buccal
• Routes for Drug Administration.

  Oral:

  • Method: Swallowed and absorbed through the gastrointestinal tract.
• Routes for Drug Administration.

  Intravenous (IV):

  • Method: Directly into the bloodstream for rapid effect.
• Routes for Drug Administration.

  Intramuscular (IM):

  • Method: Injected into muscle tissue for moderate absorption speed.
• Routes for Drug Administration.

  Subcutaneous (SC):

  • Method: Injected under the skin for slower absorption.
• Routes for Drug Administration.

  Inhalation:

  • Method: Breathed into the lungs for rapid absorption.
• Routes for Drug Administration.

  Topical:

  • Method: Applied to the skin or mucous membranes for local effect.
• Routes for Drug Administration.

  Sublingual/Buccal:

  • Method: Placed under the tongue or in the cheek pouch for direct absorption into the bloodstream.
• Protein Binding:

  • Definition: The extent to which a drug binds to plasma proteins (e.g., albumin) in the blood.
  • Implication: Highly protein-bound drugs have less free drug available for action but a longer duration of effect.
• Bioavailability:

  • Definition: The fraction of an administered dose of a drug that reaches the systemic circulation in an active form.
  • Factors: Influenced by absorption and first-pass metabolism.
• Biliary Excretion:

  • Definition: The elimination of drugs and their metabolites via bile into the intestine.
  • Outcome: Ultimately excreted in the feces.
• Half-Life:

  • Definition: The time it takes for the concentration of a drug in the bloodstream to reduce by half.
  • Implication: Determines the dosing interval and duration of action.