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BIO EQUIVALENCE STUDIES
BY ANUSHA
BIOPHARMACEUTICS &
PHARMACOKINETICS
It is commonly observed that there are several formulations
of some drug, some drug, and similar dosage forms meant to be given by
some route. So, the substitution of one product for another can be made
as they are equally effective therapeutically.
Objectives for Bioequivalence Studies
 If a new drug is intended to substitute for an approved medicinal
product as a Pharmaceutical equivalent or alternative. The equivalence
with that product should be shown or justified.
 Bioequivalence studies should be performed to ensure the clinical
performance of such drug products
SOME IMPORTANT TERMS
Equivalence: It is a relative term that compares drug products with respect
to specific characteristics or function or to a definite set of standards.
Chemical Equivalence: Indicates two or more drug products contain the
same labelled chemical substance as an active ingredient.
Pharmaceutical Equivalence: Indicates that two or more drug products are
identical in strength, purity, quality, and content uniformity, and
disintegration and dissolution characteristics.
Bioequivalence: It is a relative term that denotes that the drug substance in
two or more identical dosage forms reaches the systemic circulation at the
same relative time to the same relative extent
SOME IMPORTANT TERMS
Therapeutic Bioequivalence: Indicates two or more drug products that
contain some therapeutically active ingredient elicit identical
pharmacological effects.
DESIGN OF BIOEQUIVALENCE STUDIES
• The test and reference drug formulation must contain
- Pharmaceutically equivalent drug
- In the same dose strength
- In a similar dosage form
- Given by the same route of administration
• Approval from the testing unit consists of both single and multiple dose
studies.
STUDY DESIGNS
1) Fasting study: Did for immediate-release or modified-release oral
dosage forms
 Male and female subjects are used
 Blood sampling is done at appropriate intervals to obtain the plasma-
drug concentration time profile
 Subjects should be in a fasting condition (at least 10 hr before drug
administration and 4 hr after administration)
2) Food intervention study:
 Studies are conducted after a high-fat and high-calorie meal
 Subject is in fasting conditions for at least 10 hr before
administration, and a meal is given 30 minutes before dosing ( no food
is given for at least 4 hours after dosing)
 Done for the modified release dosage form and for the immediate
release form if bioavailability is affected by food
3) Multiple dose (steady state) study:
 Done for oral extended-release (controlled-release) drug products
 Three consecutive Cmin measured on three consecutive days to
determine steady state
4) Cross over designs:
 Each subject receives a test and a reference drug product
For example:
• Latin square crossover design
 Each formulation is administered just once to each subject and once in
each study period
 Unlike a parallel design, all the subjects do not receive the same
formulation at the same time in a given study period
Latin square crossover design for 6 or 12 subjects to compare three
different formulations X, Y, Z
Subject number Study period 1 Study period 2 Study period 3
1, 7 X Y Z
2, 8 Y Z X
3,9 Z X Y
4,10 X Z Y
5,11 Z Y X
6,12 Y X Z
Advantages:
 Minimize intersubject variability
 Minimize intrasubject variability
 Minimize variability due to time effect
Drawbacks:
The study takes a long time, as an appropriate washout period
is essential
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