BIOM 3090 Lecture 5: BIOM 3090 class notes lec 5
9 Jun 2018
School
Department
Course
Professor
Pharmacokinetics –I
Physiochemical Factor in Transfer of Drugs Across Membranes
- most drugs are administered into one body compartment and move to their
site of action
o drugs must PERMEATE various barriers that separate compartments
(i.e. cell membranes)
- intravenous: dump
things into the compartment
o biotransformation: metabolized by the liver
o proportion of drug is always moving around, being absorbed and
being eliminated
- absorption, distribution, metabolism and excretion of a drug (active
pharmaceutical ingredient) involves transport across cell membranes, which
is affected by several drug characteristics
o molecular size and structural features
o degree of ionization
o relative lipid solubility of ionized/non-ionized forms
o affinity and binding to serum and tissue proteins
o Oil and water test: take drug and put it in a graduated cylinder →
gives an idea of the chemical structures
o Passive transport
▪ Paracellular transport: goes between the membrane
▪ Passive diffusion through cell membranes or between cells
o Carrier-mediated transport: ions have to be shuttled, cant go between
or through membrane
▪ Facilitated transport
▪ Active transport
- Passive transport:
o Cell membranes consist of amphipathic lipids
