Introduction to absorption

Question 1

What is pharmacokinetics?

Answer 1

How body handles drugs.

Question 2

What is pharmacodynamics?

Answer 2

What drug does to the body

Question 3

What is absorption?

Answer 3

All processes from site of administration to site of measurement. If drug given I/V, this step doesn’t take place.

Question 4

What is bioavailability?

Answer 4

Defined here as a measure of the extent of absorption of unchanged administered compound

Question 5

What is distribution?

Answer 5

Reversible transfer of substance between site of measurement and other sites within the body.

Question 6

What is metabolism?

Answer 6

Irreversible loss of unchanged substance by chemical conversion (alters physchem properties of the drug)

Question 7

What is excretion?

Answer 7

Irreversible loss of unchanged substance

Question 8

What is elimination?

Answer 8

Irreversible loss of unchanged substance from site of measurement

Question 9

What is disposition?

Answer 9

Elimination and distribution

Question 10

PK behaviour is a function of:

Answer 10

• Physicochemical and structural properties of drug
• Dosage form
• Route of drug administration – i.v., oral, i.m.
• Physiology of the body

Question 11

Factors influencing the pharmacokinetics of a drug:

Answer 11

genetics, size, age , disease, co-administration of other drugs, environmental factors (smoking)

Question 12

Components of pharmacokinetics are:

Answer 12

• data (primary e.g. concentration, or derived e.g. cumulative amount excreted in urine)
• models

Question 13

What are the three types of PK models for ADME?processes

Answer 13

1. Single equation - integrated C = C0e-kt or differential
2. Kinetic compartmental models - number of compartments defined by the data often used for fitting of sparse clinical data – population PK modelling
3. Physiologically-based PK models - Major tool for predicting in vivo pharmacokinetics from in vitro data (Simulation workshops)