Drug Disposition- ADME Flashcards
What is drug disposition
the study of the movement of drugs across biological membranes in the body from the time of absorption until elimination.
what does ADME stand for?
Absorption/Distribution/Metabolism/Elimination
the higher the lipid solubility…
the easier/ faster it can cross cell membranes
non-ionized molecules cross…
lipid membranes more easily / more mobile
The what of a weak acid or base determines in what pH the substance will be ionized
the pKa
what does it mean when the pKa = pH
the drug is 50% ionized
acidic drugs are ionized in what type of environments?
Basic (alkaline, high pH)
Basic drugs are ionized in what type of environments?
acidic environments (low pH)
weak acid equals…
NI / I
weak base equals…
I / NI
antilog -3 equals?
Antilog 3 equals
-3 = 1/1000 or 0.001 3 = 1000/1 or 100
Antilog -2 equals?
Antilog 2 equals?
-2 = 1/100 or 0.01 2 = 100/1 or 100
Antilog -1 equals?
Antilog 1 equals?
-1 = 1/10 or 0.1 1 = 10/1 or 10
antilog 0 equals?
1
membranes are more permeable to?
non-ionized forms of drugs (lipid) soluble and no electric charges) than to ionized forms
Weak acids are absorbed from an acidic environment and will become sequestered in a more…
alkaline ( higher pH) environment
weak bases are absorbed from an alkaline environment and will become sequestered in a more…
acid (lower pH) environment
Facilitated diffusion is..
Carrier mediated, saturable, moves with concentration gradient, and does not require energy.
Active transport is…
Carrier mediated, saturable, selective, and moves substances against the concentration, gradient and requires energy
Energy for active transport can be supplied…
directly though ATP (primary) or indirectly after ATP is used to create an electrochemical gradient (secondary)
what is the term when transporters move two substances together
symporter
what is the term where on substance is exchanged for another
antiporter
What is the P-glycoprotein system?
specific form of active transport in which the transporter is an efflux pump, this protein is an expression of the MDR-1 gene
What does the MDR-1 do?
removes drugs after being absorbed into specific cells or tissue sites
what is Pinocytosis?
a specific type of endocytosis, drugs bind to the surface of the cell then the cell membranes invaginates and interoizes the drug.
