Lippincott’s Pharmacology Chapter 1

Passive Diffusion
High conc. -> low
majority of drugs work this way
does not involve carrier, is not saturable, and shows a low structural specificity

Facilitated Diffusion
involves carrier proteins
High conc -> low
no energy required, an be saturated, may be inhibited by compounds that compete for the carrier

Active Transport
Shows saturation kinetics for the carrier
drugs closely resemble naturally occurring metabolites that are actively transported across cell membranes
may be competitively inhibited

exo/endocytosis
B12 is absorbed by endocytosis; some neurotransmitters (e.g., norepinephrine) are stored in vesicles and released by exocytosis

Distribution equilibrium
when the permeable form of a drug achieves an equal concentration in all body water space

P-glycoprotein
a multidrug transmembrane transporter protein responsible for transporting various molecules , including drugs, across cell membranes; in areas of high expression, it reduces drug absorption

bioavailability
the fraction of administered drug that reaches the systemic circulation

bioequivalence
when two related drugs show comparable bioavailability and similar times to achieve peak blood concentrations

therapeutic equivalence
when two similar drug products that are pharmaceutically equivalent with similar clinical safety profiles

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