PHARMOCOKINETICS

PHARMOCOKINETICS

1. 1.ABSORPTION

   • local
   • systemic
     • enteral
       • 1. sublingual -lipid soluble -rapid absorption -bypasses liver 2.rectal route -oral rute unavalable -slow/incompleet absorption
     • parenteral
       • intravenous
       • intramuscular
       • subcutaneos
   • inhalation
   • effect of ph on absorption
   • physiological factors influencing absorption
     • surface area available for absorption
     • blood flow to absorption site
     • contact time at absorption site
     • presence of food and gastric empting
       • see metabolism for gastric emtying rate

2. 2.DISTRIBUTION

   • volume of distrobution = amount of drug in the body /plasma drug consentration
   • it is the process by witch drugs leave the blood stream and enters interstitium
   • bioavalability
     • fraction of administered drug that gains acces to the systemic circulation in a chemically uncanged form
     • factors afecting bioavalability
       • bioequivalency= comparebil bioavalibility, bioinequivalant= significant difrince in bioavailability
       • first pass metabolism
       • solubility of drugs
       • chemical instability
       • nature of drug formalation
   • factors of distribution
     • blood flow
     • capillary permeability
     • capillary structure
     • blood brain barrier
     • placental barrier
     • binding of drugs to plasma proteins
       • see pg 24 of notes
     • drug structure
       • hydrophobic (lipid soluble) hydrophhilic (water soluble)
   • volume of distribution

3. 3.METABOLISM

   • clinical implications of drug binding to plasma proteins
   • effects of bio transformation
     • terminate action
     • inactive drug - active metabolite
     • toxic metabolite from less toxic drug
     • form active metabolite from active drug
   • phases of drug metabolism
     • enzymes responsible for biotransformation located in smooth endoplasmic reticulum of liver
     • phase 1
     • phase 2
   • factors affecting drug metabolism in humans
     • genetic differences
     • age differences
     • hormonal control of drug
     • effect of diseases on drug

4. 4.ELIMINATION

   • drug ecretion in case of renal impairment
   • factors influencing gastric emptying rate
     • volume of meal
       • high volume of liquid decrease gastric empting
     • temp of meal
       • cold meals increase emting rate
     • composition & viscosity
       • fat inhibits gastric secretion witch decrease rate of empting.  Increased viscosity decrease rate of emting
     • emotions
       • depressive inhibits gastric mtility thus decrease emting
     • efects of drugs
   • HALF - LIFE
     • plasma protein binding
     • pharmacokinetic pattern
     • renal/hepatic diseases
     • active metabolites
     • enterohepatic circulation
     • volume of distribution
     • clinical significance
       • rate of elimination
       • duration of action
       • intervals between doses
       • time to steady state
       • time for complete elimination
   • mechanism of drug elimination
     • renal excretion
     • liver metabolism
   • process
     • process of biliary excretion
     • process of breast milk excretion
     • process of pulmonary elimination
     • process of fecal excretion of drugs

5. exstas

   • therapeutic index
     • toxic dose
     • effective dose
   • e cell membrane
   • physiological changes with aging
   • factors governing the fate of drug in the body