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Questions and Answers
What does a successful drug comprise?
What are the phases of drug action?
What are the components of ADME?
Absorption, Distribution, Metabolism, Excretion
What does the pharmaceutical phase involve for orally administered drugs?
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Which property influences drug dissolution?
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Passive diffusion is the only process for drug absorption.
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What is meant by pharmacodynamics in drug action?
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The process of drug absorption through the GIT membrane to circulation is known as ______.
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Which transport method is often used for polar drugs?
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What is the main function of the pharmacokinetic phase?
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Study Notes
Drug Action
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A successful drug is composed of three key factors: activity, **ADME (Absorption, Distribution, Metabolism, Excretion) **, and safety (Toxicity).
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The pharmaceutical phase of drug action involves the disintegration of a pill's components in the gastrointestinal tract (GIT), followed by the release and dissolution of the drug.
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The pharmacokinetic phase is the study of how the body absorbs, distributes, metabolizes, and eliminates a drug (ADME).
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The pharmacodynamic phase explores how a drug interacts with its specific biological target at a molecular level and the subsequent pharmacological effects that result.
Physicochemical Properties and Phases of Drug Action
- The most effective drug for binding interactions isn't necessarily the most successful drug in medicine.
- A drug reaching its target is crucial for effectiveness, therefore the study of pharmacokinetic and pharmacodynamic phases is vital.
Pharmaceutical Phase
- Drug dissolution is influenced by the pH of the medium.
- Weakly acidic drugs dissolve better in alkaline regions of the GIT and vice versa.
Pharmacokinetic Phase: Absorption
- Drug absorption includes the passage of the drug from the GIT into the bloodstream.
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Passive diffusion.
- Para- and transcellular are passive processes and dominate (~90% of drug absorption).
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Transcellular: occurs through the cell membrane or cytoplasm, relatively fast, and may occur throughout the GIT wall.
- Lipid-soluble unionized drugs dissolve in the membrane and are driven through by a concentration gradient.
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Paracellular: occurs through aqueous pores between cells, slower, and is mainly present in the small intestine.
- Primarily for polar, small molecules.
- Carrier-mediated facilitated transport is typically seen with some polar drugs, commonly those similar to endogenous compounds that rely on specific membrane carrier systems (e.g., methotrexate).
- Ionization plays a role in drug absorption.
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Description
This quiz covers the essential phases of drug action, including the pharmaceutical, pharmacokinetic, and pharmacodynamic phases. Understand how ADME factors into drug effectiveness, and the significance of bonding interactions in pharmacology. Test your knowledge on how drugs interact with biological targets and their impact on health.
