This document summarizes key concepts regarding bioequivalence studies. It defines bioequivalence as the absence of a significant difference in the rate and extent to which the active ingredient becomes available at the site of drug action when administered at the same molar dose under similar conditions. The document discusses study designs such as fasting, food effect, and multiple dose studies. It also covers regulations, biowaivers, and the purpose of bioequivalence studies to demonstrate that generic drug products are therapeutically equivalent to the brand name version.

1. BIOEQUIVALENCE AND DRUG
PRODUCT ASSESSMENT: IN VIVO
SUBMITTED BY :
KRISHNAPRIYA V H
1ST SEM M.PHARM , REGULATORY AFFAIRS
DEPARTMENT OF PHARMACEUTICAL SCIENCE
PUTHUPALLY , KOTTAYAM

2. CONTENTS
• INTRODUCTION
• DEFINITIONS
• STUDY CONSIDERATIONS
• BIOEQUIVALENCE STUDY DESIGNS
• BE REGULATIONS
• BIOWAIVERS
• PURPOSE OF BIOEQUIVALCE STUDY
• REFERENCE

3. INTRODUCTION
• Bioequivalence (BE) is the sole objective is to measure and compare formulation
performance between two or more pharmaceutically equivalent drug product.
• Simply the BE studies are performed to compare the bioavailability of the generic
drug product to the brand name product.
• This study is ensuring uniformity in standard of quality, safety, and efficacy of
product.
• BE /BA study data are required during the New Drug Application (NDA) as per
schedule Y
• The FDA (Food and Drug Administration) publishes guidance for BE studies (see 21
CFR 320.25,or www.fda/gov/eder/guidance )

4. • Sponsors may also request meeting with FDA to review the study design for a
specific drug product.
• The FDA believes that products classified as therapeutically equivalent can be
substituted for each other, with the full expectation that the substituted product
will produce equivalent clinical effects and safety profile as the original product.
• Both the BA and BE focus on the release of drug substance from it’s dosage
form and subsequent absorption to the systemic circulation.

5. Definitions
By USFDA
The absence of a significant difference in the rate and extend to which the active
ingredient or active moiety in pharmaceutical equivalents or alternatives become available
at the site of drug action when administered at the same molar dose under similar
condition in an appropriately designed study.
By WHO
Two pharmaceutical products are bioequivalent, if they are pharmaceutically
equivalent or pharmaceutical alternatives ,and their bio availabilities ,in terms of rate
(Cmax & tmax ) and extent of absorption (AUC) ,after administration of the similar molar
dose under the same conditions, are similar such a degree that their effects can be
expected to be essentially the same

6. 1. AUC = Area under the curve
• The are under the drug
concentration in plasma
/serum/whole blood v/s time
curve
2. Cmax = maximum observed
concentration
3. Tmax = maximum time to
reach the Cmax

7. Study considerations
The basic design for bioequivalence study is determined by:
• Scientific question and objectives to be answered
• Nature of reference material and dosage form, to be tested
• The availability of analytical methods
• Pk and Pd of drug substance
• Route of administration
• Benefit risk and ethical consideration(testing in humans)

8. BE study designs
The FDA provides the guidance for the performance of: In
vitro dissolution and In vivo bioequivalence studies which
include(solid oral dosage form):
1. Fasting study
2. Food intervention study
3. Cross – over study designs
4. Multiple dose (steady-state )study

9. Fasting study design
• This study is required for all immediate release and modified release
oral dosage forms.
• Both male and female subjects are included.
• Overnight fasting is required(at least 10 hrs).
• After administration of drug ,fasting continued up to 4 more hrs.
• Blood sampling is performed before dose and at different intervals
after dose.
• Plasma drug concentration-time profile is obtained.
• No other medication given at least 1 week prior to study.

10. Food intervention study
• It uses single dose, randomized, 2 treatment, 2 period
crossover study.
• Conducted using meal conditions that have greatest effect on
GI physiology.
• Meal containing high calories(50% of total caloric content) and
fat (800-1000 cal) is taken.
• After a overnight fast of 10 hrs, meal is given 30min prior to
dosing.
• The meal is consumed over 30min with administration of
drug(with 240ml of water) immediately after meal.
• No food is allowed 4hrs after dosing.
• Study on drugs like ibuprofen and naproxen which is affected
by food.

11. Cross over study designs
• Each subject receives the test and reference drug product.
• Latin Square Crossover designs are used for BE study in
human volunteers .
• These Latin Square designs plans the clinical trials so that
each subject receives each drug product only once.
• Enough time between medications for elimination of drug
is given.
• Possible crossover effects are minimized by sequence or
order in which drug products are given to subject.

12. Latin square cross-over study designs
• Latin square cross-over study designs for a BE study in human volunteers,
comparing three different drug formulations (A,B,C) or four different formulations
(A,B,C,D) are described.
• Latin square study designs plans the clinical trail so that each subject receives
each drug product only once, with adequate time between medications for the
eliminations of the drug from the body.
• In this design ,each subject is his own control and subject to subject variation is
reduced.

13. Latin square cross over design for BE study of three drug product (A,B,C) in
6 human volunteers
DRUG PRODUCT
Subject Study period 1 Study period 2 Study period 3
1 A B C
2 B C A
3 C A B
4 A C B
5 C B A
6 B A C

14. Advantages
• It minimizes the inter subject variability in plasma drug levels.
• Minimizes carry over effects
• Minimizes the variation due to time effect.
• Make it possible to focus more on the formulation variables which is
the key to success for any BE study.
Dis advantages
• The randomization is required
• The study takes long time due to the washout period
• When the number of formulation to be tested is more , the study
become more difficult.

15. • Period
period refers to the time period ,in which a study is performed A two-
period study is a study that is performed on two different days (time
periods) separated by a washout period.
• sequence
A sequence refers to the number of different orders in the treatment
groups in a study. For example, a two-sequence, two-period study would be
designed as above: where R = reference and T = treatment. The same
reference and the same test are each given twice to the same subject. Other
sequences are possible. In this design, Reference-to-Reference and Test-to-
Test comparisons may also be made.

16. For example : a two sequence ,two period study would be designed as
follows
where R= Reference
T= Treatment
Sequence 1
Period 1 Period 2
T R
Sequence 2
R T

17. Multiple dose (steady state) study
design
 Multiple doses of same drug are given consecutively to
reach steady state plasma drug levels.
 The multiple dose study is designed as steady state,
randomized, 2 treatment, 2 way, crossover study
comparing equal dose of test and reference.
 To ascertain that the subjects are at steady state, three
consecutive trough concentrations (Cmin) are determined.

18. BE regulations
• The FDA published it’s BA &BE regulations under title 21 of the code
of federal regulations (21 CFR)
• This regulations are divided in to sub parts
Sub part A : general provision
Sub part B: procedures for determining the BA of the drug product
Sub part C: BE requirements ,these are the set of forth requirements for marketing a
drug product.

19. Biowaivers
• The term biowaiver is applied to a drug regulatory approval process when a
dossier (application ) is approved based on the evidence of BE.
• The biowaiver means that the in vivo BA and BE studies may be waived(i.e.
not necessary for the drug product approval)
• A biowaiver is applicable when the drug substance(s) in test and
reference products are identical.
• A biowaiver may also be applicable if test and reference products contain
different salts provided that both belong to BCS Class I (high solubility and
high permeability).

20. • In 1995, US department of health and human service and US-FDA
started the BCS classification system with the aim of granting so called
Biowaiver for SUPAC.
• Applicant can request Biowaiver for oral dosage forms and oral
solubilized dosage forms .
• Biowaivers could also be granted for the drug product in the same
dosage forms but different strength similar in active and inactive
ingredients to a drug product from the same manufacturer , both the
drug product were required to meet an appropriate In vitro test
approved by FDA

21. Biopharmaceutical classification system
• The BCS is a frame work for classifying drug substance based on
solubility and intestinal permeability .
Class Solubility Permeability
Class 1 High High
Class 2 Low High
Class 3 High Low
Class 4 Low Low

22. Purpose of BA/BE study
• BA studies are performed for both approved active drug ingredients
and therapeutic moieties not yet approved for marketing by the FDA.
• New formulations of active ingredients must be approved by FDA
before marketing.
• FDA ensures that the drug product is safe and effective for its labelled
indication for use.
• The drug product must meet all applicable standards of industry,
strength ,quality and purity.
• BE studies are used to compare the BA of the same drug from various
drug product.

23. • For un marketed drug that do not have full NDA approval by the FDA,
in-vitro – in vivo BE studies must be performed on the drug
formulation proposed for marketing as a generic drug product.
• These studies demonstrating evidence of safety efficacy
• In vivo BA studies are also performed for new formulation of active
drug ingredients that have full NDA approval and are approved for
marketing.

24. References
1. Generic drug product development by Leon Shargel , Isadrdore
kanfer ( page no: 219- 239)
2. Marvin C. Meyer et. al; “Bioequivalence of Methylphenidate
Immediate-Release Tablets Using a Replicated Study Design to
Characterize Intrasubject Variability”; April 2000, Volume 17, Issue 4,
pp 381–384.
3. Sam H. Haidar et.al; “Bioequivalence Approaches for Highly Variable
Drugs and Drug Products”; January 2008, Volume 25, Issue 1, pp 237–
241.
4.Biopharmaceutics and pharmacokinetics –A teratise : DM
Brahmankar ,Sunil B Jaiswal page No: 339-350.

25. THANKYOU