Integrated pharmacokinetics distribution

Question 1

What is the determines the concentration of free drug

Answer 1

• Concentration gradient and
  the direction of diffusion
• Binding to plasma protiens

Question 2

Acidic reversible binding to plasma proteins

Answer 2

Acidic & neutral drugs bind that bind to albumin such as warfarin

Question 3

basic reversible binding to plasma proteins

Answer 3

Basic drugs bind to β-globulins such as quinine

Question 4

Process of drug binding with plama proteins

Answer 4

• Free and bound drugs are in a dynamic equalibrium
• Highly bound to plasma proteins which is less available for drug action
• One drug can displace other drug binding of other drug
• Thermodynamic motion, collision; thermal energy dominate the electrostatic forces

Question 5

Barriers for distributing the drug

Answer 5

• Cell arrangements
• Active transporters
• Size and lipid solubility

Question 6

Blood flow effecting drug distribution

Answer 6

• High: heart, brain, lungs, kidney, glands
• Low: skin, muscle
• Negligible- bone, teeth, hairs, cartilage

Question 7

Tissue accumulation

Answer 7

• Highly lipid soluble drugs accumulate
  acute - thiopental
  chronic
• Possible redistribution of drugs influenced by kentics

Question 8

Blood Brain Barrier

Answer 8

• Diffusion only possible for lipid soluble drugs
• The integrity compromised during meningitis (allowing access for antibiotics)
• Active transport possible

Question 9

Blood Placental Barrier at tight junction

Answer 9

• Lipid solubility and size of the drug determine the distribution to foetus.
• Drug use in pregnancy: Risk adverse/toxic teratogenic effects during pregnancy and
  neonatal toxicity during labour

Question 10

Theoretical volume of plasma

Answer 10

Vd = total vol of drug/Plasma conc

Question 11

Drug accumulates in tissues if

Answer 11

• ## Vd > 40 litres

Question 12

Drug restricted to plasma and interstitial fluid

Answer 12

Vd < 10 litres