Chapter 2 : Drug Design Approaches

Topics covered in this snack-sized chapter:



Drug Design Approaches arrow_upward


  • Medicinal chemistry deals with:
    • Designing,
    • Development,
    • Scientific synthesis of pharmaceutical drugs by combining the principles of chemistry and pharmacology.

    Molecular structure depiction

  • It also deals with:
    • Identification
    • Synthesis of various therapeutic chemical agents
    • Evaluation of the properties of existing drugs

    Process of Discovering Drugs arrow_upward


  • The entire process deals with designing and development of certain chemical compounds that can be used in development of medicines for deterrent and treatment of diseases in human beings as well as in animals.
  • The process involves the following steps:
    • Discovery
    • Optimization
    • Development

    Step 1: Discovery arrow_upward


  • Consists of the identification and production of new active substances usually called lead compounds.
  • Lead can originate from synthetic organic chemistry, from natural sources or from biotechnological processes.


    • Step 2: Optimization arrow_upward


  • Deals mainly with the synthetic modification of the lead structure in order to improve potency, selectivity and lessen toxicity
  • Its characteristics are the establishment and analysis of structure-activity relationships (SAR).

    • Step 3: Development arrow_upward


  • Consists of:
    • The optimization of the synthetic route for bulk production.
    • Modification of the pharmacokinetic and pharmaceutical properties of the active substance to render it suitable for clinical use.
  • This may cover optimization of properties associated with:
    • Chemical formulation: involves a thorough chemical analysis of the active substances and identification of their chemical structures.
    • Solubility: involves enhancing the solubility of the substances so that they can be used to prepare the organic compounds present in drugs.
    • Elimination: of unpleasant taste or irritation.
    • Reduction: of pain at site of injection.

    Objectives of Chemical Modifications arrow_upward


  • Chemical modifications to the lead substances are done in order to:
    • Improve the recognition as well as the binding geometries (generally known as pharmacophores) of the candidate compounds a well as lead substances.
    • A pharmacophore is an abstract description of molecular features which are necessary for molecular recognition of a ligand by a biological macromolecule.
    • Improve the physicochemical properties of those molecules that motivate the necessary pharmacokinetic/pharmacodynamics (PK/PD) as well as the toxicological profiles.

    • Adapt and optimize the synthetic route for mass scale syntheses and production of hundreds of kilograms or even more.

    • Impart a thorough knowledge of adequate synthetic practice in the perspective of large scale reactions
    • Switch over to more rigorous goods manufacturing practice (GMP) requirements for material sourcing, handling, chemistry etc.
    • Identify "triage" compounds that do not provide series displaying suitable SAR and chemical characteristics that can be used for long-term potential for development, and improving the rest series for the principle activities along with the secondary activities
    • Evaluate the physiochemical properties so that the agent can actually cure patients (both human as well as animals) when injected or administered


    Thank You from Kimavi arrow_upward


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