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Flashcards in Pharmacology Deck (17):
1

what is meant by drug absorption

the process by which a drug enters the body from its site of administration

2

what is meant by drug distribution

the process by which a drug leaves the site of administration, enters the blood and subsequently the tissues perfused by the blood.

3

what is meant by drug metabolism

the process by which tissue enzymes (principally in the liver – hepatic metabolism) catalyze the chemical conversion of a frequently lipid soluble drug to an often less active and more polar form that is more readily excreted from the body

4

what is meant by drug excretion

the processes that remove the drug, or its metabolites, from the body (principally the kidneys – renal excretion)

5

what is meant by drug elimination

The linked processes of metabolism and excretion

6

what factors affect drug absorption

solubility

chemical stability

lipid to water partition coefficient

7

what is acids relationship with protons

donates protons

8

what is base's relationship with protons

accepts protons

9

what does the degree of ionisation depend on in drugs

pKa of the drug

local pH

10

what can calculate Proportions of ionised and unionised drugs

the Henderson-Hasselbalch equation

11

what is the Henderson-Hasselbalch equation

pKa - pH = log(AH/A-)
for acid

pKa - pH = log(BH+/B)
for base

12

what facilities the absorption of weak acids

pH of the stomach lumen

13

where are bases readily absorbed

small intestines

14

what is oral availability

the fraction of drug that reaches the systemic circulation after oral ingestion

15

what is systemic availability

fraction that reaches the systemic circulation after absorption

16

what are ionised and unionised drugs distribution

if they are not bound to plasma protein (e.g. albumin, α1-acid glycoprotein) they can move freely by diffusion

17

what are the only drugs that move readily by diffusion

unionised drugs