Lecture 9

Question 1

Upper and lower rectum have what type of tissue

Answer 1

Upper - Simple Columnar
Lower - strat. squamous non-keratinized->keratinized near sphincter = HIGHLY FOLDED

Question 2

Which areas of rectum show high drug absorption?

Answer 2

Strat. Squamous and non-keratinized

Question 3

Problem with rectal drugs

Answer 3

Low residence time (stimulates bowel movement)

Question 4

Oral absorption first step

Answer 4

Disintegration/ deaggregation of particle

Question 5

Dissolution action

Answer 5

Getting drug out of particles and into solution

Question 6

What can cross GI barrier for absorption?

Answer 6

Free Active Pharmaceutical Ingredient (API)

Question 7

Dissolution

Answer 7

The rate at which the drug releases (has to release at certain time)

Question 8

Biorelevant dissolution times are…

Answer 8

Variable from person to person

Question 9

T/F: There can be variation with dissolution within same patient

Answer 9

True

Question 10

T/F: Greater GI residence leads to lower absorption

Answer 10

False (higher absorption)

Question 11

T/F: Gastric pH and residence changes can happen if formulation is taken before meals

Answer 11

True (fed state may be a little less predictable, but still possible)

Question 12

Factors influencing solubility

Answer 12

Buffer capacity
Bile salts
Regional Fluids
Other Drugs
Potential issues from endogenous substrates

Question 13

Strong Buffer Capacity…

Answer 13

Resists changes, holds pH well

Question 14

Buffer capacity/pH-
solubility relationship

Answer 14

Higher the buffer capacity and pH, higher solubility

Question 15

Higher solubility of drug means what for absorption?

Answer 15

More of the drug is able to be absorbed

Question 16

T/F: Transporters and enzymes vary along GI tract

Answer 16

True

Question 17

T/F: Diet and Chemical Exposure varies in GI

Answer 17

True

Question 18

Two big challenges for GI Physiology Clinical Considerations

Answer 18

Pharmacogenetics
Genomics

Question 19

T/F: Drug-nutrient and drug-drug interactions are common in GI tract

Answer 19

True

Question 20

Drug distribution is different between…

Answer 20

Different compounds based on their physiochemical properties

Question 21

Where do lipophilic compounds partition vs hydrophilic?

Answer 21

Lipo- Fatty tissues
Hydro- Tissues where endothelium is permissive (spleen/liver)

Question 22

Nature of pharmacokinetic processes

Answer 22

Described by concentration time profiles (blood/plasma vs. time)
Compartments represent kinetically similar tissues/spaces
Processes can be reversible/irreversible
Can be linear/non linear
Fast and slow processes tend to “disappear”

Question 23

What two main factors dictate distriubtion?

Answer 23

Perfusion and Permeability rates

Question 24

Drug distribution restricted to one tissues vs at diff rates trend (linear/non-linear?)

Answer 24

Restricted - Linear
Different rates - non linear

Question 25

Bioavailability Definition

Answer 25

The rate and extent of drug absorption

Question 26

Absolute Bioavailability definition

Answer 26

is the AUC of a given dosage form compared with the AUC of the same dose injected intravenously

Question 27

Relative bioavailability

Answer 27

Refers to the AUC of a given dosage form compared to an arbitrary reference standard

Question 28

T/F: Bioequivalent means the therapeutic effect of two dosage forms are equivalent

Answer 28

False