Flashcards in Introduction to Biopharmaceutics Deck (23)

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1

## Biopharmaceutics is..

### The study of how physiochemical properties of drugs, dosage forms and routes of administration affect the rate and extent of drug absorption.

2

## Why is Biopharmaceutics important?

### There is a knock on effect on the drug, and in turn - the patient.

3

## What does the body to the drug? (4)

###
ADME

Absorption

uptake into system

Distribution

transfer to body fluids and tissue

Metabolism

transform into metabolites

Excretion

removed

4

## How can we know the amount of drug in the body?

###
Plasma concentration

The higher the plasma concentration, the higher drug concentration.

5

## What is the Therapeutic window?

### The minimum effective concentration.

6

## C max (plasma conc max), what would this be in IV administration?

### Same as plasma drug concentration at 0 because no absorption phase.d

7

## What is the Toxic range?

### The minimum toxic concentration.

8

## Why are repeated doses needed?

### Because plasma concentration decreases over time and fall before therapeutic range.

9

## What is the onset of time?

### The time where the plasma concentration first exceeds the therapeutic window.

10

## What is AUC?

### the exposure of the body to the drug.

11

##
Equation for AUC

IV administration

### Co (initial conc) / elimination rate constant

12

## What is the plasma half life?

### Time taken for the plasma concentration of a drug to fall by 50%

13

## Equation for plasma half life:

### t1/2 = t2 - t1

14

## Is the plasma half life constant?

### Yes because it follows first order kinetics.

15

## Long plasma half life means...

### more time can pass before taking a second dose.

16

## What is the volume of distribution?

### an indication of how likely a drug is to remain in the body or go into tissues.

17

## Equation for volume of distribution:

###
Vd = D / Co

D = IV dose (mg)

Co = initial plasma conc mg per L

18

## Clearance is...

###
the volume of plasma from which the drug is eliminated per unit time L per H.

hepatic and renal clearance.

19

## Equation for AUC in oral administration:

###
D x F / CL

D = dose

F = bioavaliability

CL = clearence

20

## Bioavaliability, F, is..

### the fraction of the dose that reached systemic circulation.

21

## What is F in IV administration?

### 1 or 100%

22

## What is F in oral administration?

### F < 1 due to pre-systemic effects

23