Workshop on GMP and Quality Assurance of
Multisource Tuberculosis Medicines
Kuala Lumpur – Malaysia
21-25 February 2005
Stability Studies
(emphasis on FPPs)
Theo Dekker, D.Sc., consultant to WHO
Research Institute for Industrial Pharmacy
North-West University, Potchefstroom, South Africa
iiftgd@puk.ac.za
Feb 2005
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TG Dekker – WHO, Malaysia
Abbreviations
API
BP
CEP
EOI
FDC
FPP
ICH
Int.Ph.
R&D
TB
USP
25ºC/60%RH
Feb 2005
Active pharmaceutical ingredient
British Pharmacopoeia
EU certificate of suitability
Expression of interest
Fixed dose combination
Finished pharmaceutical product
International Conference on Harmonization
International Pharmacopoeia
Research and development
Tuberculosis
United States Pharmacopeia
25ºC ± 2ºC / 60% RH ± 5% RH etc.
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TG Dekker – WHO, Malaysia
The perspective
 Pharmaceutical R & D provides the foundation of the
activities aimed at ensuring that the patient receives
an FPP (product) that consistently meets established
standards & specifications of
 Safety
 Efficacy
 Quality
 The FPP should be stable - and thus retain these
standards – throughout the shelf-life,
 if kept in the original packaging and
 when correctly distributed, stored & handled
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TG Dekker – WHO, Malaysia
Topics for discussion
1.
2.
3.
4.
5.
Objective of stability studies
Glossary / definitions
Example of transport monitoring
Study protocol/requirements
Rifampicin containing FDCs to exemplify


Expression of degradants
Assay / degradation analytical requirements
6. Closing remarks
Feb 2005
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TG Dekker – WHO, Malaysia
The objective of stability studies
The purpose of stability testing is to provide evidence
on how the quality of a drug substance [API] or drug
product [FPP]
 varies with time
 under the influence of a variety of environmental
factors such as temperature, humidity, and light,
and
 to establish a re-test period for the API (drug
substance) or
 a shelf life for the FPP (drug product) and
recommended storage conditions.
ICH QA1(R2)
Feb 2005
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TG Dekker – WHO, Malaysia
Glossary [ICH QA1(R2)]
Re-test period
 The period of time during which the API is expected to remain
within its specification and, therefore, can be used in the
manufacture of a given drug product, provided that the API
has been stored under the defined conditions
 After this period, a batch of API destined for use in the
manufacture of a FPP should be re-tested for compliance with
the specification and then used immediately
 A batch of drug substance can be re-tested multiple times and
a different portion of the batch used after each re-test, as long
as it continues to comply with the specification
 For most biotechnological/biological substances known to be
labile, it is more appropriate to establish a shelf life than a retest period. The same may be true for certain antibiotics
Feb 2005
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TG Dekker – WHO, Malaysia
Glossary (2)
Re-test date
The date after which samples of the API should be examined
to ensure that the material is still in compliance with the
specification and thus suitable for use in the manufacture of a
given drug product [if stored under defined conditions]
Expiry (expiration) date
The date placed on the container label of an FPP designating
the time prior to which a batch of the FPP is expected to
remain within the approved shelf life specification
 if stored under defined conditions, and after which it must
not be used {no re-testing !!}
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TG Dekker – WHO, Malaysia
Glossary (3)
Stress testing (API)
 Studies undertaken to elucidate the intrinsic stability of the
IPA. Such testing is part of the development strategy and is
normally carried out under more severe conditions than those
used for accelerated testing.
Stress testing (finished product)
 Studies undertaken to assess the effect of severe conditions
on the finished product. Such studies include photostability
testing (see ICH Q1B) and specific testing on certain products,
(e.g., metered dose inhalers, creams, emulsions, refrigerated
aqueous liquid products).
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TG Dekker – WHO, Malaysia
Glossary (4)
Accelerated testing
 Studies designed to increase the rate of chemical degradation
or physical change of an API or FPP by using exaggerated
storage conditions as part of the formal stability studies. Data
from these studies, in addition to long term stability studies,
can be used
 to assess longer term chemical effects at non-accelerated
(real-time) conditions &
 to evaluate the effect of short term excursions outside the
label storage conditions such as might occur during
shipping
 Results from accelerated testing studies are not always
predictive of physical changes
Current accelerated conditions for solid orals: 40ºC/75%RH
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TG Dekker – WHO, Malaysia
Example of shipping conditions (1)
UNICEF ↔ Kampala (1989): Temperature
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TG Dekker – WHO, Malaysia
Example of shipping conditions (2)
UNICEF ↔ Kampala (1989): Relative humidity
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TG Dekker – WHO, Malaysia
Stability protocol/report
The following elements (see Guidelines, Annex 2)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Feb 2005
Info on batches tested (commercial formula)
Unit composition (or cross-reference)
Container-closure system (commercial!!)
Literature and/or supporting data
Stability specifications (only for FPPs)
Analytical methods – stability indicating (cross-reference)
Stability plan (schedule)
Tabulated test results (including specifications)
Analysis/discussion of data (statistical if negative trend)
Re-test or shelf-life proposal (including storage condition)
Post approval commitments
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TG Dekker – WHO, Malaysia
Stability batches
 Stability data for three primary batches



The formulation and manufacturing process should be
the same as proposed for marketing
In container-closure system proposed for marketing
Preferably manufactured from different API batches
 Full info on batches tested (tabulated format) e.g.:







Feb 2005
Batch number
Manufacturing date
Manufacturing site
Batch size (in kg & in number of units)
Container-closure (primary packaging)
Date of initial analysis (release)
API batch number
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TG Dekker – WHO, Malaysia
Tablets – stability batches data - example
1st
2nd
3rd
Batch number
Manufacturing date
Manufacturing site
Batch size (kg)
Batch size (number of units)
Batch type (full-scale, pilot, etc.)
Primary packaging
Date initial analysis
Batch number of API
Feb 2005
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TG Dekker – WHO, Malaysia
Stability specifications
Stability studies should include testing of those
attributes (parameters) of the FPP that are
 susceptible to change during storage and thus
 are likely to influence quality, safety, and/or efficacy.
 The testing should cover, as appropriate, the physical,
chemical, biological, and microbiological attributes,
preservative content (e.g., antioxidant, antimicrobial
preservative), and functionality tests (e.g., for a dose
delivery system)
From ICH Q1A(R2)
Feb 2005
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TG Dekker – WHO, Malaysia
Tablets – stability specifications
 Parameters for tablets that are often omitted:
 Tablet strength, friability and moisture can change
with time
– if not in release specs, include in stability
– these are interrelated, also with dissolution
– these are inexpensive
 Microbial limit at release and end-of-shelf
 Dissolution specification must be same as for
release
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TG Dekker – WHO, Malaysia
Example - FPP specs – uncoated tablets
Attribute
Release limits
Stability limits
Appearance
Full description
Same as release
Identification
At least 1 method
Dimensions
Diameter, etc
Average mass
w.r.t. theoretical
Mass uniformity
Ph.Eur/USP/Int.Ph
Not required for
stability studies.
Not regarded as
variables for
product.
Water content
Product specific
Tablet hardness* Product specific
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Same as release?
Same as release
TG Dekker – WHO, Malaysia
Example of FPP specs – uncoated tabs (con.)
Attribute
Release limits
Stability limits
Friability *
≤ 1 % (normally)
Same as release
Dissolution
Set per product
Same as release
Disintegration
Not required if dissolution is done
Related subs.
(degradants)
Only if formed
during production
95.0-105.0%,
unless justified
Required. Limits
to one decimal
May be 90.0105.0% if justified
Skip-testing
End-of-shelf
Assay (content)
Microbial limits
* Tests not necessary at release if done in-process
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TG Dekker – WHO, Malaysia
FPP stability specs. – special for FDCs
 Degradants (related substances) must be stated &
calculated in % with respect to the parent API, not the
sum of the APIs, e.g.
 Rifampicin / isoniazid tablets. Rifampicin quinone
(degradant) as % of rifampicin (not of all peaks in HPLC)
 If 2 APIs react with each other, then the degradant to
be stated with respect to worst case, e.g.
 Rifampicin / isoniazid tablets. Isonicotinyl hydrazone forms
from the 2 APIs. Specification: % hydrazone with respect
to rifampicin (worst-case in mass balance).
 Unknown degradants – with respect to worst case
 Dissolution – include all APIs (e.g. FDCs in the USP)
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TG Dekker – WHO, Malaysia
Isonicotinyl hydrazone expression
The reaction (simplified):
Isoniazid + rifampicin → hydrazone + ..
Rel. MM
137
829
845
MM Ratio (÷137) 1.0 mg
6.0 mg
6.2 mg
FDC mg
FDC ratio



75 mg
1.0 mg
150 mg
2.0 mg
At 100% reaction, no rifampicin left, 67% isoniazid intact
Hydrazone to be expressed with respect to rifampicin
Rifampicin worst-case in mass balance
Feb 2005
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TG Dekker – WHO, Malaysia
Stability indicating analytical methods
 Analytical methods must be suitable for the purpose
of stability testing (stability indicating), particularly in
the case of
 Assay of the API(s) in the FPP
 Determination of the degradants (related substances)
 Determination of preservatives
 If the same as release testing methods, a reference
will suffice
 Release methods should include validation for stability
 Compendial methods
 May not be suitable (e.g. non-specific like titration)
 May not exist for the particular purpose (e.g. degradants)
Feb 2005
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TG Dekker – WHO, Malaysia
Rifampicin containing FDC
assay/degradation methods (1)
Particular degradants to consider:
1.
2.
3.
4.
5.
Isonicotinyl hydrazone
Rifampicin quinone
Rifampicin N-oxide
3-Formyl rifamycin (present in FDCs?)
25-Desacetyl rifampicin

All to be determined & expressed with respect to
rifampicin
 Assay method(s) must be specific (considering
degradants)
 A method for degradants to be developed
Feb 2005
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TG Dekker – WHO, Malaysia
Rifampicin containing FDC
assay/degradation methods (2)
Examples of methods:
 USP 28 (2, 3, 4 FDC capsules/tablets)
 Assay method (stability indicating when tested in our lab)
C-18 column, gradient chromatography (see USP)
 No specification/test for degradants
 S. Singh et al. (NIPER)
 Various HPLC methods, mainly related to isonicotinyl
hydrazone determination, simultaneously with rifampicin
and isoniazid (one example given here)
 RIIP analysis (Research Institute for Industrial Pharmacy)
 For assay of rifampicin and degradants – other APIs with
a separate method
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TG Dekker – WHO, Malaysia
USP FDC assay method
DAD1 A, Sig=238,4 Ref=360,100 (C:\HPCHEM~1\ASTERIX\AMR\03060406.D)
5.443 - Pyrazinamide
mAU
350
300
Pyrazinamide
250
Rifampicin
13.044 - Rifampicin
Isoniazid
150
4.182 - Isoniazid
200
switch
0
0
5
10
15
19.585
16.544
16.993
10.999
10.010
10.379
3.626
2.643
3.042
50
11.555
11.872
9.695
100
20
Isonicotinyl hydrazone in area of gradient “switch”,
difficult for quantification
Feb 2005
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TG Dekker – WHO, Malaysia
A NIPER HPLC method
S. Singh et al., Pharm. Pharmacol. Commun., 6, 405-410 (2000)
Feb 2005
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TG Dekker – WHO, Malaysia
RIIP HPLC chromatogram
27.413 - Rifampicin
DAD1 A, Sig=254,4 Ref=360,100 (AMR_RIF\07090407.D)
3-Formyl rifamycin
mAU
50
0
5
Quinone
Hydrazone
10
15
24.070 - 3-Formylrifamycin
0
18.861 - Rifampicin Quinone
10
14.171 - Hydrazone
20
7.389 - Rifampicin N-Oxide
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N-Oxide
Other 3 APIs
40
rifampicin
20
25
30
min
C-18: methanol/phosphate buffer pH 7.0 : 6/4
Signals well separated
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TG Dekker – WHO, Malaysia
4FDC products – degradation results
Product
Primary container
A
Pvdc/Alu
B
HDPE
securitainer
8
C
Pvdc/Alu
Age (months)
N-oxide (%)
Hydrazone (%)
Quinone (%)
3-Formyl (%)
Total related subs.
10
7.2
1.3
5.0
10.2
2.6
8.5
5.0
12.8
8
The 4FDC tablets instable: Isonicotinyl hydrazone main degradant
Container permeability may play a role (Alu/Alu > Pvdc/Alu?)
Feb 2005
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TG Dekker – WHO, Malaysia
Testing frequency & storage conditions
Solid oral dosage forms (tablets, capsules):
Condition▼
Month►
0
3
6
9 12 18 24 36
30ºC / 65% RH (zone IV) X X X X X X X X
40ºC / 75% RH (accel)
X X
25ºC / 60% RH (zone II)
X X X X X X X
 Zone IV is real-time condition for prequalification
project, unless otherwise justified
 Zone II only if justified (may be fall-back for zone IV)
 ASEAN proposal for zone IV: 30ºC / 75% RH
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TG Dekker – WHO, Malaysia
Stability storage facilities
RIIP facilities (110 m3)
Three rooms: 25ºC/60%RH; 30ºC/65%RH; 40ºC/75%RH
Feb 2005
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TG Dekker – WHO, Malaysia
Significant changes during stability
1. A 5% change in assay from its initial value (or failure to
meet acceptance criteria when using biological methods)
2. Any degradation product exceeding its acceptance criterion
3. Failure to meet the acceptance criteria for appearance,
physical attributes, and functionality test (e.g., colour, phase
separation, resuspendibility, hardness, dose delivery per
actuation);
4. and, as appropriate for the dosage form:
 Failure to meet the acceptance criterion for pH; or
 Failure to meet the acceptance criteria for dissolution for
12 dosage units
5. Dissolution specifications for release and stability must
be the same (otherwise possible BE change)
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TG Dekker – WHO, Malaysia
Pitfall
 The assay value is still within the limits

but the change during stability is more than 5.0%
 Example






Feb 2005
Release assay limit: 95.0 – 105.0%
Stability assay limit: 92.5 – 105.0%
Release assay: 101.0% (within spec)
24-Month assay: 93.0% (within spec)
Loss in potency: 8.0% !!
This is a significant change !!
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TG Dekker – WHO, Malaysia
Reporting of stability data
 Stability should be presented in well
constructed tables (stability data sheets)
 See Annex 2 for an example
 Relevant administrative information must appear
on sheet
 Acceptance criteria for each attribute must be
included in the table for quick reference purposes
 Result sheets must bear date and responsible
person signature / QA approval
Feb 2005
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TG Dekker – WHO, Malaysia
Evaluation of stability data
1. The data show no/little variation with time


Statistical analysis not required (justify)
Proposed shelf-life = 2 x real-time data (R), but not more
than R + 12 months (30 months max)
2. The data show trend(s)


Statistical analysis required [see ICH Q1A(R2)]
Proposed shelf-life depends on the statistical analysis
3. Commitment



Feb 2005
For confirmation of provisional (tentative) shelf-life, realtime data are required
First 3 production batches on stability
Follow up stability testing (FUST) – one batch per year
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TG Dekker – WHO, Malaysia
Closing remarks
 Stability testing is an essential part of the
process of ensuring that the patient receives a
product that meets established standards of
safety, efficacy and quality
 Sound planning and execution of stability
studies are important
 Valuable time may be lost if the data are insufficient
 Always include all attributes which may change with time
(e.g. water content, friability & tablet strength in the case
of uncoated tablets) – pay upfront and save later
Feb 2005
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TG Dekker – WHO, Malaysia