Bioavailability and Bioequivalence

Question 1

Define biopharmaceutics.

Answer 1

Biopharmaceutics is the study of how the physical and chemical properties of drugs, dosage forms, and routes of administration influence the rate and extent of drug absorption, distribution, metabolism, and excretion

Question 2

What is biovailability?

Answer 2

Bioavailability refers to the fraction of drug administered that reaches systemic circulation and is available to exert its therapeutic effect.

Question 3

What is bioequivalence?

Answer 3

Bioequivalence refers to the relationship between two drug products that are pharmaceutically equivalent and have similar bioavailability to such a degree they can be expected to have the same therapeutic effects.

Question 4

Mention 5 factors affecting bioavailability/bioequivalence.

Answer 4

1. Formulation factors e.g. excipient
2. Manufacturing process
3. Physicochemical characteristics of active ingredients e.g. particle size, partition coefficient
4. Physiological factors e.g. sex, age, disease state
5. Route of administration
6. Drug interactions

Question 5

Define pharmacokinetics.

Answer 5

Pharmacokinetics is the study of the time course or the quantitative measure of the adsorption, distribution, metabolism and excretion of drugs.

Question 6

Define clinical pharmacokinetics.

Answer 6

Clinical pharmacokinetics is the application of pharmacokinetic principles in patients with the aim of designing indivisualised drug regimens to produce optimal therapeutic outcome while minimising the risk of adverse effects.

Question 7

What is a pharmaceutical equivalent?

Answer 7

Pharmaceutical equivalents are drug products that contain the same active ingredients and are of the same dosage form, route of administration, and concentration, and meet the same or comparable standards in the official compendia.

Question 8

What is an interchangeable pharmaceutical product?

Answer 8

A product that is therapeutically equivalent to a reference product.

Question 9

What is a reference product?

Answer 9

It is a pharmaceutical product with which a new product is intended to be interchangeable in clinical practice.

Question 10

What is therapeutic substitution?

Answer 10

Therapeutic substitution involves replacing a prescribed drug with a different chemical entity that is expected to have the same therapeutic effect.

Question 10

What is generic substitution?

Answer 10

Generic substitution is the practice of replacing a brand-name drug with a generic version that is bioequivalent and pharmaceutically equivalent.

Question 11

What are the two steps involved in bioavailability?

Answer 11

1. Dissolution
2. Absorption

Question 13

Mention 6 cases where bioequivalence studies are necessary.

Answer 13

1. When a new product is introduced by one manufacturer when a similar product is already licensed to another manufacturer.
2. When the manufacturer of a licensed product wished to vary the excipients or manufacturing process of the product.
3. When a drug has a narrow therapeutic index
4. High excipient to drug ratio
5. Fixed combination drugs with systemic action
6. Sustained-release or modified-release drugs