Module 1B rational dosage form design

Question 0

What are the bio pharmaceutical considerations in the design and manufacture of drugs (6)

Answer 0

1. Aqueous solubility
2. Lipid-aqueous partition coefficient
3. Absorption across membranes
4. Protection from acidic environment
5. Metabolic inactivation
6. Prodrugs

Question 1

Outline the physiochemical and bio pharmaceutical properties of a drug that are considered when developing a suitable dosage form (5)

Answer 1

1. pH solubility and dissolution rate
2. Partition coefficient
3. Stability or degradation rate in the body
4. Susceptibility to metabolic inactivation
5. Mechanism of transport through membranes

Question 2

Importance of polymorphism in drug dosage form design (4)

Answer 2

Polymorphism is the ability of a chemical species to crystallise into more than 1 crystal habit
This causes different:
-dissolution rates and solubility
Having a dramatic impact on bioavailability when dissolution is the rate limiting step in absorption

Question 3

When is controlling the release of drug desirable (2)

Answer 3

When compounds are:
- absorbed rapidly through mucous membranes or
- removed rapidly from the site of action
The approach normally reduces the systemic side effects of the drug

Question 4

Describe the primary advantages of delivering drugs via alternative routes vs oral route (3)

Answer 4

1. Avoids absorption and metabolic barriers in GI tract
2. Provides systemic availability when oral admin is contraindicated
3. Provide a concentration-time profile similar to IV dosing

Question 5

Describe the rate limiting steps in oral drug absorption (3)

Answer 5

1. Disintegration
2. Dissolution
3. Absorption

Question 6

Define biopharmaceuticals (2)

Answer 6

Allows for rational design of drug products

-delivers the drug at a specific rate to optimise thereputic effect and minimise adverse effects

Question 7

Define drug delivery system

Answer 7

System of delivering drugs to the target site

• drug product
• drug dosage form

Question 8

Define bio equivalent drug product

Answer 8

Pharmaceutical equivalents whose bioavailability does not show a significant difference

Question 9

Define generic drug product

Answer 9

Bio equivalent as well as the rate and extent of systemic drug absorption is not statistically different under:

               - the same experimental conditions
               - route of administration
               - similar dosage form
               - same chemical form
               - same dose