Primary Mechanism of Drug Membrane Transport
The most important mechanism for drug passage across biological membranes is:
- Passive diffusion — Correct Answer
- Pinocytosis
- Filtration
- Active transport
Explanation:
Correct Answer: Passive diffusion
Passive diffusion is the most important mechanism for majority of drugs. It is a random movement of drug molecules from higher to lower concentration, requiring no cellular energy and no carrier protein.
Factors Governing Passive Diffusion
- Concentration gradient: Greater difference → faster diffusion.
- Drug molecular size: Smaller molecules move more rapidly.
- Lipophilic nature: Higher lipid solubility → higher diffusion.
- Temperature: Lower temperature → slower diffusion.
- Membrane thickness: Thicker membrane → slower diffusion.
Why Other Options Are Wrong
- Active transport — requires energy; moves drugs against concentration gradient.
- Pinocytosis — important for large macromolecules; minor role in pharmacology.
- Filtration — mainly significant in glomerular filtration and CSF removal.
📚 About this Topic — Veterinary Pharmacology and Toxicology
This multiple choice question is from Veterinary Pharmacology and Toxicology, Veterinary Science. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Veterinary Pharmacology and Toxicology to strengthen your preparation.
