Distribution Flashcards
“Compartments” Concept
Groups of tissues/ fluids for which the rates of update/clearance of a drug are similar; distribution of drugs involves movement between different compartments
Factors that affect distribution
Physiochemical properties of the drug
Concentration gradient between blood and tissue
Blood flow : tissue mass
Affinity of drug for tissue
Body fluids compromise ________ % of body weight
57%
Intracellular fluid constitutes _________%
40%
Extracellular fluid constitutes _____%
17%
Apparent Volume of Distribution
Apparent volume necessary to contain the entire amount of a drug if were evenly distributed throughout the body at the concentration present
Examples of tissues with high relative blood flow
Brain, Heart, Kidney, Endocrine Organs
Examples of tissues with low relative blood flow
Bone, Fat , inactive muscle
Blood Brain Barrier
Tight junctions between capillary endothelial cells and glial cells surrounding the pre capillaries force drugs to cross cell membrane to enter, CSF is constantly produced keeping space around the CNS “washed”
What mechanisms are responsible for drug efflux out of the CNS?
Active Transport mechanisms ___________________________
P-gp
Plasma protein binding is an important means of
Distribution
Acidic drugs bind primarily to
Albumin
Basic drugs primarily bind to
Alpha1-acid glycoproteins, beta-globulins and some others
Plasma protein binding is generally (reversible/irreversible)
Reversible
Bound drug is generally confined to the
Blood
