Biopharmaceutics

Question 1

What is biopharmaceutics?

Answer 1

study of the relationship between the physicochemical properties of a drug, the dosage form, and route of administration on the rate and extent of systemic absorption
-influences the time course of drug concentrations in the body
-influences clinical response (onset, duration, intensity)

Question 2

What are some factors that biopharmaceutics has an influence on?

Answer 2

drug liberation
rate of dissolution
rate of absorption; extent of absorption (F)

Question 3

What are the clinical factors that impact the choice of dosage form? What are the pharmaceutical factors?

Answer 3

clinical factors:
-primary disease location
-patient and compliance
-effect desired
pharmaceutical factors:
-availability of formulation
-PC characteristics
-stability of dosage form

Question 4

True or false: drug must be in solution to be absorbed

Answer 4

true

Question 5

What is the equation used to describe dissolution of drug from dosage form?

Answer 5

Noyes-Whitney equation

Question 6

Summarize the Noyes-Whitney equation.

Answer 6

dC/dt=d/h x S x (Cs-C)
dC/dt: rate of dissolution
d/h: diffusion coefficient
h: width of diffusion layer
S: surface area of drug
Cs: solubility (drug conc in diffusion layer)
C: conc in bulk solution

Question 7

What is the rate limiting step in dissolution?

Answer 7

diffusion from diffusion layer to bulk solution