Drug discovery phase involves identifying and designing new drug molecules with potential therapeutic effects. This is the initial stage in developing a new drug, focused on identifying compounds that could become safe and effective medicines. Key Steps for Drug Discovery Phase: Target Identification and Validation A target is usually a protein, enzyme, or receptor involved … Read more
Preclinical evaluation phase tests drug safety and efficacy in lab and animal studies before human trials. This phase tests the lead compound in non-human subjects (cells and animals) to assess its safety, effectiveness, and behavior in the body. Major Objectives of Preclinical Evaluation Phase: Evaluate safety and toxicity Study pharmacokinetics (PK): what the body does … Read more
Clinical trial phase evaluates drug safety, dosage, and effectiveness in humans through structured studies. Clinical Trial Phase Involves systematic testing in humans, divided into several phases: Phase 0 (Optional): Microdosing studies in a few volunteers Assesses basic pharmacokinetics and drug-target interaction Phase I: Conducted in healthy volunteers (20–100) Focuses on safety, tolerability, and pharmacokinetics Determines … Read more
Pharmacovigilance monitors, detects, and prevents adverse drug effects to ensure safe and effective medicine use. Once a drug is on the market, it’s still under continuous surveillance through pharmacovigilance. Definition of Pharmacovigilance: It is the science and activities relating to the detection, assessment, understanding, and prevention of adverse effects or other drug-related problems. Key Activities: … Read more
Drug-receptor interactions describe how drugs bind to receptors, influencing potency, efficacy, and selectivity. Drugs produce their effects mainly by interacting with receptors—specific macromolecules usually found on or within cells. Key Concepts of Drug-Receptor Interactions: Receptor: A protein molecule that receives chemical signals from outside a cell. Ligand: A molecule (e.g., drug) that binds to a … Read more
This article explains about the Signal transduction mechanisms explain how receptors convert external signals into cellular responses. Signal Transduction Mechanisms Signal transduction is the process by which a chemical signal (like a drug or hormone) is transmitted from the outside of the cell to the inside, leading to a cellular response. Most drugs act through … Read more
GPCRs are membrane receptors that transmit signals via G-proteins, regulating many physiological processes. Structure of GPCRs: Single polypeptide chain with 7 transmembrane α-helices Coupled to G-proteins (GTP-binding proteins) inside the cell Mechanism of GPCRs: Agonist binds to receptor (outside of cell) Receptor undergoes conformational change Activates G-protein by exchanging GDP for GTP G-protein dissociates into … Read more
This article explains about the Ligand-gated ion channels are receptors that open or close ion pathways in response to specific ligands. Structure of Ligand-gated ion channels: Multi-subunit protein with a central ion pore Opens or closes in response to ligand (drug/neurotransmitter) binding Mechanism: Ligand binds to receptor Ion channel opens Specific ions (Na⁺, K⁺, Ca²⁺, … Read more
Regulation of receptors involves upregulation or downregulation, affecting drug sensitivity and therapeutic response. Regulation of Receptors Cells dynamically regulate receptors in response to various stimuli to maintain homeostasis. Key mechanisms include: Receptors can change in number or sensitivity in response to drug exposure: Upregulation Increase in receptor number or sensitivity. Occurs after prolonged use of … Read more
Classification of receptors is based on structure, function, and response, including ion channel, GPCR, enzyme, and nuclear types. Classification of Receptors Receptors are classified based on their structure and signal transduction mechanism: Ionotropic Receptors (Ligand-Gated Ion Channels) Response in milliseconds. Example: Nicotinic acetylcholine receptor, GABA-A receptor. Metabotropic Receptors (G-Protein Coupled Receptors – GPCRs) Response in … Read more
