1. A SEMINAR ON
TYPES OF EQUIVALENT
AND
MEASUREMENT OF BIOAVAILABILITY
PRESENTED BY:
GANDHI SONAM MUKESHCHANDRA
1ST YR M.PHARM
DEPT. OF INDUSTRIAL PHARMACY

2. CONTENTS
 Introduction & importance
 Types of equivalents
 Methods for assessing the
bioavailability

3. Introduction & Importance
 There are several formulations of same
drug, in the same dose, in a similar
dosage form and given through same
route. Substitution of one product for
another can be made equally effective,
therapeutically as per standards. In order
to ensure clinical performance of such
drug products bioequivalence studies
should be performed.

4. EQUIVELENTS
 It is a term that compares one product is
similar with respect to a specific
characteristic or function to another, or to
the defined set of the standards.
There are four types of equivalences:
 1. Chemical equivalence
 2. Pharmaceutics equivalence
 3. Therapeutic equivalence
 4. Bioequivalence

5.  Chemical equivalence:
two or more formulations contain the
same labelled chemical substance as an
active ingredient in the same amount.
 Pharmaceutics equivalence:
two or more formulations are identical in
strength, quality, purity, content
uniformity and disintegration and
dissolution characteristics.

6.  Therapeutic equivalence:
It indicates that two or more drug products
that contain the same therapeutic active
ingredients elicit same pharmacologic effects
and can control the disease to the same
extent.
 Bio equivalence:
It is a relative term which denotes that the
drug substance in two or more identical
dosage forms reaches systemic circulation at
same relative rate and to the same relative
extent i.e. their plasma concentration-time
profiles will be identical without significant
statistical differences.

7. Methods for assessing the bioavailability
 Pharmacokinetics methods
This method reflects the therapeutic
effectiveness of a drug. Thus these are indirect
methods.
 Plasma-level time studies
 Urinary excretion studies
Pharmacodynamic methods
This method involves direct measurement of
drug effect on a physiologic process as a function
of time.
 acute pharmacologic response
 therapeutic response

8. Pharmacokinetic methods
 Cmax: it gives indication whether drug is
sufficiently absorbed systematically to
provide therapeutic response
 Tmax: the peak time that gives an
indication of rate of absorption
 AUC: it gives a measure of the extent of
absorption or amount of drug that
reaches the systemic circulation.

9.  Extent of bioavailability can be
determined by following equations
 F=[AUC]oral Div/[AUC]iv Doral
 Fr=[AUC]test Dstd/ [AUC]std D test

11. Pharmacodynamic methods
1.(dXu/dt)max: it is obtained from the peak of plot
b/w rate of excretion v/s mid point time of urine
collected period.
2. (tu)max: it is analogues to the tmax of plasma
level data, its value decrease as absorption rate
increases.
3. Xu: it is related to the AUC of plasma level data
and increases as the extent of absorption
increases.

12.  Extent of bioavailability can be
determined by following equations
 F = (Xu α)oral Div/ (Xu α)iv Doral
 Fr= (Xu α)test Dstd/ (Xu α) std Dtest

13. Acute pharmacological response
 In this method acute pharmacologic
effect such as change in ECG or EEG
readings, pupil diameter etc. is related to
the time course of the given drug.
 Bioavailability can be determined by
construction of pharmacological effect-
time curve as well as dose response
graph.

14.  THERAPEUTIC RESPONSE
 This method is based on observing the
clinical response to a drug formulation
given to patients suffering from disease
for which it is intended to be used.

15. References
 Dr. Shobha rani, R Hiremath, Textbook of
Biopharmaceutics & Pharmacokinetics. Pg
no.32-47.
 D.M. Brahmankar, Sunil B. Jaiswal.
Biopharmaceutics & Pharmacokinetics A
TRETISE.Pg.no.285-289.
 Milo Gibaldi. Biopharmaceutics & Clinical
Pharmacokinetics. Fourth edition. Pg.15
 Leon shargel, applied Biopharmaceutics
and pharmacokinetics. Fifth
edition.2005.Pg.no.460-465.

16. THANK YOU