Pharmacology Chapter 4 - Pharmacokinetics Flashcards
Pharmacokinetics
Study of drug movement throughout the body.
Pharmakon -
greek word for poison.
Four Basic Pharmacokinetic Processes are…
Absorption (movement from site of administration into blood), Distribution (movement from blood to intestinal space of tissue and then into cells), Metabolism (enzymatic alteration of drug structure), and Excretion (movement of drug and metabolites out of the body.)
Matter
anything that has mass.
Element
a substance that can not be broken down into simpler substances (O, C, etc). Each element has a set of properties that distinguish it from other elements.
Atom
smallest particle of an element that retains the characteristics of that element. Every atom has energy and ability to do work.
Compounds
substance made from elements are called compounds. (H20)
Molecules
smallest units of a compound that still have the properties of that compound. (In H20, the ratio of H and O is 2:1, so the formula is H20.)
Molecules are generally neutral.
Ions
Electrically charged molecules
Polar Molecules
molecules with uneven distribution of electrical charge. A polar molecule is any molecule with unbalanced charge distrubtion.
Polar Molecules and water…
Because water molecules are polar, they attract each other as well as other polar molecules and ions.
Solutes/Solvent
Solutes that dissolve in a SOLVENT are soluble.
Non polar substances Do/Do Not dissolve in water?
They DO NOT
Like dissolves?
Like.
Acid - what kind of donor is it?
proton donor. (a substance that releases hydrogen ions when mixed with water.)
Base - what kind of donor is it?
substance that separates in water…PROTON ACCEPTOR.
pH -
0-14. Acid is 0, most basic is 14.
Ionization -
the process of becoming charged (ion.)
Acids tend to become ___ in basic media and bases tend to ____ in acidic media.
Ionized
Diffusion - def
movement of a molecule/substance from a higher to a lower concentration.
Osmos - def
movement of water molecules through a semi-permeable membrane from a higher to a lower water concentration.
Ion Trapping or pH Partitioning
When there is a ph gradient on either side of a membrane, acidic drugs will accumulate on the alkaline side, and basic drugs will accumulate on the acidic side.
Membrane structure - basic
layers of cells - double layer of molecules - phospholipids - phospholipid bilayer.
Three ways to cross a cell membrane
Through channels or pores - very few do this.
With aid of a transport system - carrier protein, requires some energy.
Direct Penetration of membrane - most common.
Polar Molecules and ions Can/Cannot cross membrane.
CANNOT
Charged molecules Can/cannot cross membrane.
Cannot
Factors affecting absorption
Rate of dissolution, surface area, blood flow, lipid solubility pH partitioning
Routes of Administration - two types.
Enteral (via GI tract - Oral.) and Parenteral - outside the GI tract, like IV, IM, etc.
Intravenous Advantages and Disadvantages
Advantages - no barrier to absorption, rapid onset, use of large fluid volumes.
Disadvantages - high cost, inconvenience, difficult to administer, irreversible..etc.
Intramuscular - barrier?
Only barrier to absorption is capillary wall.
Intramuscular Advantages/Disadvantages
Adv - rate of absorption can be fast, etc. Disadvantages - painful, risk of local infection, and nerve damage.
Subcutaneous - similar to?
similar to IM.