Lecture 2-3: General Principles of Pharmacokinetics Flashcards
What is pharmacokinetics
Describes the process by which the body handles the drugs presented to it
What are 4 the pharmacokinetic processes
- Absorption
- Distribution
- Metabolism
- Excretion
What are ways drugs can be absorbed
- Oral intake
- Inhalation
- Injection
Drugs enter the bloodstream and interact/bind with ___
Proteins
Do bound or free drugs leave bloodstream and go to site of action
Free
Size of ____ determines what size of molecules can get in and out of bloostream
Fenestrated capillaries
What is the distribution process of drugs
- Enter liver or other sites of bio transformation
- Either enter bile to be eliminated or can be reabsorbed or enter circulation
- Free drug when migrates to site of action or inactive tissues
How are drugs eliminated
- Transported in Bile and eliminated in feces
- Air
- Urine via kidney
What is the major site of elimination/excretion
Kidney—> urine
What are the 3 kinds of passive transported
- Simple diffusion
- Channel mediated
- Transporter mediated
What is passive/simple diffusion
Water soluble and lipid soluble drugs penetrate membrane
What does carrier mediated transport depend on
- Structure specifics- # of transporter molecules
- Competition for binding
- Tmax- # of transporters finite
What are the 2 types of carrier mediated transport
- Facilitated diffusion
- Active transport (ATP)
What is filtration
Glomerular filtration in kidney
What is transcytosis (pinocytosis)
Drug molecules and fluid get engulfed by vesiculation of cell membrane
Mechanisms of membrane penetration follow ____ gradient
Concentration gradient
Are most drugs in clinical use weak or strong acids/bases
Weak
The extent of ionization is described by what equation
Henderson hasselbachs
In order for a drug to be lipid soluble does it need to be ionized or non-ionized and why
Non-ionized, if it is ionized it will bind H20 and become large and charged therefore will not be able to go through membrane and will be eliminated
Do acidic drugs have lower or higher pKa’s
Lower
Do basic drugs have lower or higher PKa’s
Higher
What is the ionized form of an acid
A-
What is the unionized form of an acid
HA
What is the ionized and unionized form of basic drug
Unionized form: B
Ionized form: BH+