This document summarizes a stability study report on various types of stability testing for pharmaceutical products. It discusses real-time stability testing which monitors products under recommended storage conditions. Accelerated stability testing exposes products to elevated stress conditions to accelerate degradation. Retained sample testing analyzes stability samples from marketed batches. The International Council for Harmonization guidelines provide standards for long-term, intermediate, and accelerated testing conditions and frequencies. Shelf life is calculated using the Arrhenius equation by plotting degradation rates at different temperatures to extrapolate stability at room temperature.

1. STABILITY STUDY
PTE 603 ASSIGMENT
By Ogoh Adakole Augustine
An M.Sc. Student of Pharmaceutical Technology
University of Jos
Lecturer: Dr J.D Audu-Perer

2. OUTLINE
• INTRODUCTION
• OBJECTIVES AND USES
• IMPORTANT OF STABILITY STUDIES
• TYPE OF STABILITY STUDIES
REAL-TIME STABILITY TESTING
ACCELERATED STABILITY TESTING
RETAINED SAMPLE STABILITY TESTING
• ICH HARMONISED TRIPARTITE GUIDELINE
• STEPS INVOLVED IN CALCULATING OF SHELF LIFE
• REFERENCES
2

3. INTRODUCTION
• Stability of a pharmaceutical drug products is the ability of a drug
formulation in a specific container-closure system to remain within its
physical, chemical, microbiological, therapeutic and toxicological
specifications throughout its shelf life
• Biopharmaceutical products in storage change as they age, but they
are considered to be stable as long as their characteristics remain
within the manufacturer's specifications (Robert, 2003).
• The number of days that the product remains stable at the
recommended storage conditions is referred to as the shelf life
(Robert, 2003).
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4. INTRODUCTION CONT’D
• A measure of how a pharmaceutical product
maintains its quality attributes over time
• Stability testing is used to:
 Provide valid evidence as to how the quality of drugs changes
with time.
 Establish shelf life of pharmaceutical drug product or to
establish a re-test period for the active pharmaceutical
ingredient
For registration purposes
 To determine the recommended storage conditions of drug
product.
To determine the right container and packaging materials.
4

5. IMPORTANT OF STABILITYTESTING
 Quality assurance to the patient as in regard to good treatment
outcomes
 Economic considerations.
 Legal requirement for regulatory bodies
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6. OBJECTIVESAND USES (Thorat et al., 2014)
Objective Type of study Use
To select adequate formulation &
container Closure system .
Accelerated Development of
the product
To determine shelf life &storage
condition.
Accelerated&
Real time
Development of
the product& of
the registration
dossier
To substantiate the claimed shelf
life.
Real time Registration
dossier
To verify that no changes have
been introduced in the
formulation or manufacturing
process that can adversely affect
the stability of the product.
Accelerated&
Real time
Quality assurance
in general,
including quality
control
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7. TYPES OF STABILITYTESTING (Thorat et al.,
2014)
Real-Time stability testing
Retained sample stability testing
Accelerated stability testing
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8. Real-Time stability testing
• In real-time stability testing, a product is stored at recommended
storage conditions and monitored until it fails the specification
(Robert, 2003).
• Real-time stability testing is normally performed for longer
duration of the test period in order to allow significant product
degradation under recommended storage conditions (Thorat et
al., 2014).
• The period of the test depends upon the stability of the product
which should be long enough to indicate clearly that no
measurable degradation occurs and must permit one to
distinguish degradation from inter-assay variation(conditions
(Thorat et al., 2014).
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9. Real-Time stability testing cont’d
• During the testing, data is collected at an appropriate frequency.
• The reliability of data interpretation can be increased by
including a single batch of reference material for which stability
characteristics have already been established (Thorat et al.,
2014)
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10. ICH Climatic zone and Long term condition (Thorat et
al,2014)
Climatic
zone
Climatic
definition
Major
countries
Region
Mean annual
partial water
press
Long term
testing
condition
1 Temperate Europe,
Russia
<15ºC/,<11hP
a
21ºC/45%RH
2 Subtropical&
Mediterranea
n
Japan
,Southern
Europe
>15ºC-
22ºC/>11-
18 hPa
25ºC/60%RH
3 Hot & Dry Iraq, India >22ºC>15hPa 30ºC/35%RH
4a Hot & Humid Iran ,Egypt >22ºC>15-
27hPa
30ºC/65%RH
4b Hot & very
humid
Brazil,
Singapore
>22ºC>27hPa 30ºC/75%RH
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11. Retained sample stability testing (Thorat et al.,2014)
• This method is normally use for marketed product that require
stability study.
• In this study, stability samples, for retained storage for at least
one batch a year are selected.
• If the number of batches marketed exceeds 50, stability samples
from two batches are recommended to be taken.
• At the time of first introduction of the product in the market, the
stability samples of every batch may be taken, which may be
decreased to only 2% to5% of marketed batches at a later stage.
• In this study, the stability samples are tested at predetermined
intervals i.e. if a product has shelf life of 5 years, it is
conventional to test samples at 3, 6, 9, 12,18, 24, 36, 48, and
60 months
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12. ACCELERATED STABILITYTESTING
 All medicinal products decompose with time
Stability study to predict the shelf life of the product, by
accelerating the rate of decomposition, preferably by increasing
the temperature of reaction conditions.
Studies designed to increase the rate of chemical degradation or
physical change of a drug substance or drug product by using
exaggerated storage conditions as part of the formal stability
studies (ICH, 2003).
In accelerated stability tests, a product is stored at elevated
stress conditions (such as temperature, humidity, and pH)
(Robert, 2003)
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13. ACCELERATED STABILITYTESTING CONT’D
(Thorat et al., 2003)
• In addition to temperature, stress conditions applied during
accelerated stability testing are moisture, light, agitation,
gravity, pH and package
• In accelerated stability testing the samples are subjected to
stress, refrigerated after stressing, and then assayed
simultaneously.
• comparison of the unstressed product with stressed material is
made within the same assay and the stressed sample recovery is
expressed
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14. ICH HARMONISED TRIPARTITE GUIDELINE (ICH,
2003)
• According to International Council for Harmonization(ICH),
• The long term study for drug product must be continued for a
sufficient period of time beyond 12 months to cover the shelf
life of the product.
• Intermediate storage condition data are required when a
significant change occurs prior to completion of study under
the accelerated storage condition.
• The accelerated storage condition must be >15º C above the
long term study storage conditions.
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15. Storage condition (ICH, 2003)
STUDY Storage condition Minimum time
period covered by
data at submission
Long term 25°C ± 2°C/60%
RH ± 5% RH or
30°C ± 2°C/65%
RH ± 5% RH
12 months
Intermediate 30°C ± 2°C/65%
RH ± 5% RH
6 months
Accelerated 40º C ± 2º C
75%RH ± 5%
6 months
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16. ICH HARMONISED TRIPARTITE GUIDELINE
Selection of Batches
• Data from stability studies should be provided on at least three
primary batches of the drug product.
• The primary batches should be of the same formulation and
packaged in the same container closure system as proposed for
marketing.
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17. Testing Frequency (ICH, 2003)
For Long term testing, during 1st year sampling should be done
every 3 months, during 2nd year is 6months and after 2years is
once a year.
Accelerated testing should be done at least six months and it
suggests sampling points of 0, 3, 6 months.
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18. STEPS INVOLVED IN CALCULATING OF
SHELF LIFE(Habib et al., 2015)
Based on the principle of chemical kinetics demonstrated by
Garret and Carper method
Free and Blythe method
Shelf Life Determination Based on Arrhenius Plot (Garret
and Carper method )
• The mathematical prediction of shelf life is based on the
application of the Arrhenius equation, which indicates the
effect of temperature on the rate constant, k, of a
chemical reaction of thermodynamic temperature, 1/T, is a
straight line
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19. ARRHENIUS EQUATION
• It explains the effect of temperature on rate of a reaction.
According to Arrhenius, for every 10º rise in temperature, the
speed of reaction increases about 2-3 times
K=Ae-Ea/RT
• Log K=Log A - Ea/2.303*RT
• Where, K= rate constant
• R= gas constant =1.987 cal/mole
• T = absolute temperature
• A = frequency factor
• Ea = energy of activation
• T10% = (2.303/K)*(log100/90)
• T90% = (2.303/K)*(log100/10
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20. Garret and Carper method
• 1. Keep several samples of the drug product at atleast three
temperatures, such as 40ºC, 50ºC and 60ºC.
• 2. Determine the drug content at all three storage points by
taking a number of samples and take the mean drug content. We
do this for a few weeks.
• 3. At each temperature we plot a graph between time and log
percent drug remaining. If the decomposition is first order
this gives a straight line. If it is zero order, percent drug
remaining versus time will give a straight line.
• 4. Next we take the log K or log of reaction constant on Y axis
and 1/T x 10-3 on X axis and draw a best fit line. This line is
the Arrhenius Plot, extrapolate this line to get k at 25ºC and
from this we calculate the shelf-life.
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21. Arrhenius plot for predicting drug stability at
room temp(PLOT 1)
21

22. PLOT 2
Arrhenius plot for predicting the rate
constant at ambient temperature(25ºC
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23. Calculation
If the reaction is following zero-order
• Expiration date at 25 oC = Initial potency – minimum
potency / reaction rate at 25 °C tx =Yo - Yx/ Ko
• If the reaction is following first order
• Expiration date at 25 oC (tx) = Log initial potency – log
minimum potency/reaction rate at 25 tx =log Yo – log Yx /
K1
• Where Yo = initial potency
Yx = final potency
Ko = zero order constant
K1 = first order constant
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24. FREEAND BLYTHE METHOD(based on t90)
• In this method the fraction life period is plotted against a
reciprocal temp. and the time in days required for drug to
decompose to some fraction of its original potency at room
temp.
• The log% of drug remaining is plotted against time and days
and the time for the loss line at several temp. to reach 90% of
the theoretical potency is noted by the doted line
• The log time to 90% is then plotted against 1/T and the time for
10% loss of potency at room temp. can be obtain from the
resulting straight line by extrapolation to 25 C
• Shelf life and expiration date are estimated in this way
• This approach clearly illustrate in below figure (plot a and b).
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25. Plot a Plot b
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26. SHELF LIFE DETERMINATION BASED ON REAL
TIME TESTING(Thorat et al., 2003)
1. Keep three batches for stability study at least for 1 year at one
fixed temperature.
2. Test them at 0, 1, 3, 6, 9, and 12 months for drug content. At
each testing time test a number of samples, so that you have a
mean and a standard deviation value of the result.
3. Now plot the graph of % drug content on Y axis and time on
X axis along with
confidence intervals. Where the lower 95% confidence curve
intersects minimum potency,
there you fix the shelf life.
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27. REFERENCES
• ICH (2003);International Council for Harmonisation Q1E
Report :Evaluation of stability data
• Haabib.U.B, Harum.A.R, Moshin.M and Khadija.T.T:An
Overview.(2015);Stability study of pharmaceutical products and
shelf life predition.European J Bio and Pharm Sci;2.pp30-40.
• Robert.T. Magari.(2003); Assessing shelf life using real-time
and accelerated stability test. Biopharm International;16(11)
• Thorat. P, Warad.S, Solunke. R, Ashok.S, Anagha. B, and
Asha.S.(2014);Stability study of dosage form: An inovative
step. World J of pharmacy and pharm Sci;3(2) pp1031-1050
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