Pharmacokinetics 2

Question 1

Pharmacokinetics

Answer 1

what the body does to the drug - absorption, distribution, metabolism and excretion

Question 2

pharmacodynamics

Answer 2

what the drugs do to the body - drug action and mechanism

Question 3

pH

Answer 3

the measure of the concentration of protons (H+) in a solution

Question 4

acid solutions -

Answer 4

DONATE PROTONS

and have a higher concentration of H+ than pure water

Question 5

basic solutions

Answer 5

ACCEPT PROTONS

- lower conc. of H+ than pure water

Question 6

water H+ conc.

Answer 6

1 x 10 ^ - 7 M

Question 7

pH equation =

Answer 7

• log↓10 [H+]

Question 8

pKa

Answer 8

is the pH where a drugs exists as 50% ionised and 0% unionised

(tells you what pH needed for a solution to donate/accept protons)

Question 9

pKa and acidi drugs

Answer 9

acidic drugs have a low pKa and so are more likely to be ionised in alkaline solution (high pH)

Question 10

pKa and basic drugs

Answer 10

basic drugs have a high pKa and so they are ionised in low pH

Question 11

unionised molecules are more…than ionised molecules

Answer 11

lipophilic

(lipophilic - can cross cell membranes)

Question 12

what is the Henderson Hasselbalch Equation used for?

Answer 12

to calculate the PERCENTAGE OF IONISATION of a drug in acellular compartments of different pH.

Question 13

what is the Henderson Hasselbalch Equation

Answer 13

pH = pKa +log ([A-]/[HA])

Question 14

why will al weak acid be more soluble at an acidic pH?

Answer 14

because it is uncharged and uncharged molecules move more readily through a lipid (nonpolar) environment, like the cell membrane, compared to charged molecules

same with weak base in basic pH