Medicinal Chemistry I

Medicinal Chemistry I is a core subject that explores the design, synthesis, and biological activity of drugs. It bridges organic chemistry and pharmacology to enhance understanding of therapeutic agents.

Key Highlights:

  • Studies drug classification, including antibiotics, sulfonamides, and chemotherapeutic agents.
  • Focuses on Structure-Activity Relationship (SAR) to relate chemical structure with drug action.
  • Explains mechanisms of action for various therapeutic compounds.
  • Covers drug synthesis and metabolic pathways.
  • Emphasizes physicochemical properties influencing drug absorption and efficacy.
  • Introduces principles of drug design and development.
  • Enhances skills needed for pharmaceutical research and formulation.
  • Builds a foundation for rational drug use and clinical application

Drug Metabolism: Definition and Importance

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Drug Metabolism

Drug metabolism is the chemical transformation of pharmaceuticals, primarily in the liver, converting lipophilic compounds into water-soluble metabolites for easier excretion. Key Goals of Drug Metabolism Detoxification: Converts toxic compounds into less harmful forms. Excretion: Enhances drug elimination via urine or bile. Regulation of Drug Activity: Activates prodrugs or inactivates drugs, influencing their effect. Enzymatic … Read more

Optical and Geometrical Isomerism

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Optical and Geometrical Isomerism

Optical and Geometrical Definition  Optical and Geometrical Isomerism: Stereoisomerism is a form of isomerism in which compounds have the same molecular formula and sequence of bonded atoms (constitution) but differ in the spatial arrangement of atoms or groups. It includes geometrical isomerism, which arises from restricted rotation around double bonds or ring structures leading to … Read more

Bioisosterism

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Bioisosterism

Bioisosterism Definition: Bioisosterism are structurally similar chemical groups that mimic the biological activity of another. Importance in Drug Design: Improved Activity: Replacement of groups can enhance potency and reduce toxicity. Increased Stability: Bioisosteres improve metabolic stability. Reduced Side Effects: Modification helps improve drug safety. Examples: Sulfonamide (-SO₂NH₂) as a bioisostere of carboxyl (-COOH) in diuretics. Fluorine … Read more

Chelation

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Chelation

Chelation Definition: Chelation is the formation of complexes between drugs and metal ions (e.g., Ca²⁺, Fe³⁺, Mg²⁺). Importance in Drug Action: Drug Absorption: Chelating with dietary minerals reduces absorption (e.g., tetracyclines + calcium). Toxicity Management: Chelating agents are used to remove heavy metals (e.g., lead, arsenic). Stability: It can enhance or reduce drug stability in … Read more

Protein Binding

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Protein Binding

Protein Binding Definition: Protein Binding: Drugs bind to plasma proteins (e.g., albumin, globulins) in the bloodstream, affecting their distribution and activity. Importance in Drug Action: Free vs. Bound Drug: Only free drug is active; bound drug serves as a reservoir. Drug-Drug Interactions: Competition for binding sites can increase free drug concentration and toxicity. Duration of … Read more

Hydrogen Bonding

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Hydrogen Bonding

Hydrogen Bonding Definition: Hydrogen bonding occurs when hydrogen (H) atoms interact with electronegative atoms (O, N, F). This contributes to a drug’s solubility and receptor binding. Importance in Drug Action: Water Solubility: More hydrogen bonds = better water solubility. Receptor Binding: Hydrogen bonds enhance drug-receptor interactions (enzyme active sites, DNA intercalation). Stability: Hydrogen bonds stabilize … Read more

Partition Coefficient

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Partition Coefficient

Partition Coefficient Definition: The partition coefficient (P) is the ratio of a drug’s solubility in lipid (oil) vs. water. It is often expressed as log P, which quantifies lipophilicity. $P = \frac{\text{Concentration in lipid phase}}{\text{Concentration in aqueous phase}}$ High log P (>3): Lipophilic (fat-soluble) Low log P (<1): Hydrophilic (water-soluble) Optimal log P (~1-3): Good … Read more

Solubility

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Solubility

Solubility Definition: Solubility is the ability of a drug to dissolve in a given solvent (e.g., water, lipids, organic solvents). Drugs must dissolve in biological fluids before they can be absorbed and exert their effect. Importance in Drug Action: Oral Bioavailability: Poorly soluble drugs have lower absorption and bioavailability. Drug Formulation: It determines the formulation … Read more

Ionization

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Ionization

Ionization Definition: Ionization refers to the process by which a molecule gains or loses protons, leading to the formation of charged species (ions). The extent of ionization depends on the pKa of the compound and the pH of the surrounding environment. Importance in Biological Action: Drug Absorption: Non-ionized (neutral) drugs cross biological membranes (lipid bilayers) … Read more

Medicinal Chemistry History and Development

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Medicinal Chemistry History and Development

Medicinal Chemistry History and Development has evolved over centuries, shaped by key discoveries, advancing methodologies, and a deeper understanding of biology and chemistry. Early Medicinal Chemistry History Ancient Times – Early medicinal practices in Egypt, China, and India relied on natural products and herbs for healing. Alchemy to Chemistry – Medieval alchemy laid the foundation … Read more