2.4 - Absorption

Question 1

Movement of drug form site of administration to the central compartment (blood)

Answer 1

Absorption

Question 2

Rate & Extent of disappearance of a drug from the site of administration

Answer 2

Physiologic

Question 3

Rate & extent of drug entry into systemic circulation

Answer 3

Pharmacokinetic

Question 4

Factors Affecting Absorption

Answer 4

• Dose Size
• Surface Area of the Absorption Environment
• pH of the Absorption Environment
• Degree of Perfusion
• Gastric Emotying Time

Question 5

Dose Size

Answer 5

⬆️dose = ⬆️absorption

Question 6

Absorption Environment

Answer 6

• Stomach

* Small Intestine

Question 7

Surface Area of the Absorption Environment

Answer 7

⬆️Surface Area = ⬆️Absorption

Question 8

Main site of drug absorption

Answer 8

Small Intestine

– SA = 120 m2 (villi& microvilli)

Question 9

pH of the Absorption Environment

Answer 9

• Stomach — Acidic (⬇️pH)

* SI — Basic (⬆️pH)

Question 10

Weak Acid

Answer 10

• Stomach: Non-ionized (absorbed)

* SI: ionized (excreted)

Question 11

Weak Base

Answer 11

• Stomach: Ionized (excreted)

* SI: Non-ionized (absorbed)

Question 12

Degree of Perfusion — Blood Supply

Answer 12

⬆️Perfusion = ⬆️Absorption

Question 13

– For PO drugs

– Time it takes for the stomach to empty its contents

Answer 13

Gastric Emptying Time (GET)

Question 14

Stomach

Answer 14

– Small Surface Area
– Small perfusion
— POOR ABSORPTION Environment except ASA & Ethanol

Question 15

Gastric Emptying Time (GET)

Answer 15

⬆️GET = ⬇️Absorption

Question 16

Normal Gastric Emptying Time

Answer 16

2-3 hours

Question 17

Factors that ⬆️ GET

Answer 17

• Stress
• Gastric ulcer
• Heavy exercise
• Heavy meal
• Lying on the left side
• Antimotility/ Anticholinergics

Question 18

Factors that ⬇️ GET

Answer 18

• Extremes in food temp
• Lying on the RIGHT side
• Mild exercise
• Promotility Drugs

Question 19

Pharmacokinetic Parameters

Answer 19

• Bioavailability

* Bioequivalence

Question 20

Measurement of RATE AND EXTENT of drug absorption

Answer 20

Bioavailability

Question 21

Methods

Answer 21

• Cumulative Urinary Excretion Data

* Plasma Concentration vs Time Graph

Question 22

Parameters

Answer 22

• Cmax
• tmax
• AUC

Question 23

– Maximum drug plasma concentration
– Measure BOTH rate and extent
– Most variable

Answer 23

Cmax

Question 24

– Time to reach Cmax

– Measures the RATE

Answer 24

Tmax

Question 25

– Area Under the Curve

– Measures the EXTENT

Answer 25

AUC

Question 26

Bioavailability Studies

Answer 26

• Absolute Bioavailability

* Relative Bioavailability

Question 27

– Measurement in the similarity of the bioavailability of the generic drug product and the BA of the innovator

Answer 27

Bioequivalence

Question 28

Minimum number of subjects

Answer 28

12

Question 29

Acceptable

Answer 29

(90% Confidence Interval) 0.8 (80%) - 1.25 (125%)

Question 30

– Same API, salt/ ester/ complex-
– Same dosage form, strength
– Differ in excipient, brand name

Answer 30

Pharmaceutical Equivalents

Question 31

– Same API
– May differ in:
 - salt/ ester/ complex
 - dosage form
 - dosage strength

Answer 31

Pharmaceutical Alternatives

Question 32

– Pharmaceutical Equivalents

– Bioequivalent

Answer 32

Therapeutic Equivalence

Question 33

– Differ in API

– Same drug class

Answer 33

Therapeutic Alternatives