Workshop on Quality Assurance and GMP of Multisource HIV /AIDS medicines

2005.02.28. Dr. Pogány - WHO, Shanghai 1/33

Workshop on Quality Assurance and GMP of Multisource HIV/AIDS medicines

János Pogány, pharmacist, PhD, consultant to WHO

Shanghai, 01 March 2005E-mail: [email protected]

Stability StudiesA brief overview


Subjects for Discussion

1. Definitions

2. Planning stability studies and reporting results

3. Stability testing of APIs

4. Stability testing of FPPs

5. Evaluation of stability results

6. Conclusions


DEFINITIONSRe-test dateThe 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 FPP.

Re-test periodThe 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 FPP, 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 API 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.


DEFINITIONS

Expiration date (also referred to as expiry date)The date placed on the container label of an API or a FPP designating the time prior to which a batch of the API/FPP is expected to remain within the approved shelf-life specification if stored under defined conditions, and after which it must not be used.

Shelf life (expiration dating period, conformance period)The time period during which an API or a FPP is expected to remain within the approved shelf-life specification, provided that it is stored under the conditions defined on the container label.

Planning and Reporting

Stability Studies


Stability Protocol and Report1. Batches tested2. General information3. Container/closure system 4. Literature and supporting data 5. Stability-indicating analytical methods 6. Testing plan 7. Test parameters 8. Test results9. Other requirements (post-approval commitments)10. Conclusions


Stability Protocol and Report The design of the formal stability studies for the

FPP should be based on knowledge of the behaviour and properties of the API and the FPP. High risk and low risk ARVs.

The methodology used during stability studies should be described. The test procedures applied to the stability tests on the API/FPP should be validated or verified, and the accuracy as well as the precision (standard deviations) should be recorded.


Data of API Stability Batches

The batches should be representative of the manufacturing process and should be manufactured from different batches of key intermediates.

Batch number

Date of manufacture

Site of manufacture

Batch size (kg)

Primary packing materials

Date of initial analysis


Data of Capsule/Tablet Stability Batches

Batch number

Date of manufacture

Site of manufacture

Batch size (kg)

Batch size (number of units)

Primary packing materials

Date of initial analysis

Batch number of the API The batches should be representative of the manufacturing process and should

be manufactured from different batches of APIs.

2.7 Stability TestingWHO Prequalification Project

API


Stress testing (forced degradation) Degradation factor Conditions

Thermal ≥ 60 oC

Humidity ≥ 75% RH

Acid 0.1N HCl

Base 0.1N NaOH

Oxidative 3% H2O2

Photolytic Metal halide, Hg, Xe lamp, or UV-B fluorescent

Metal ions (optional) 0.05M Fe2+ or Cu2+


Forced degradation tests To validate the stability indicating power of the

analytical procedures. To identify stability-affecting factors such as ambient

temperature, humidity and light and to select packing materials, which protect the FPP against such effects.

To identify potential degradants of the API and assess if they can be formed during manufacture or storage of the FPP.

No standard method, 10-30% degradation, stress factors, conditions and time

Solid state degradation (supporting information)


Formal (Regulatory) Stability Testing

Storage temperature(°C)

Relative humidity

(%)

Minimum time period covered by data at submission

(months)

Accelerated: 40±2 75±5 6

Intermediate: 30±2 65±5 12

Long term: 25±2 60±5 12


Stability Room1. A special cabinet for each

condition

2. Design, construction, qualification, monitoring

3. Costs of operation including R + D failures

4. Time

5. Do we need new standard conditions?


Stability results A storage statement should be proposed for the

labeling (if applicable), which should be based on the stability evaluation of the API.

A re-test period should be derived from the stability information, and the approved retest date should be displayed on the container label.

An API is considered as stable if it is within the defined/regulatory specifications when stored at 30±2oC and 65±5% RH for 2 years and at 40±2oC and 75±5%RH for 6 months.

3.11 Stability testing WHO Prequalification Project

FPP


Potential Instability Issues of FPPs

Loss/increase in concentration of API

Formation of (toxic) degradation products

Modification of any attribute of functional relevance

Alteration of dissolution time/profile or bioavailability

Decline of microbiological status

Loss of package integrity

Reduction of label quality

Loss of pharmaceutical elegance and patient acceptability


Increase in concentration of APIDuring stability studies of Artesunate, the assay results were increasing. The hydrolysis may yield artenimol and succinic acid. The latter can justify the increase in assay. The assay method is „stability indicating” but not specific.

+


Stability-indicating quality parameters

Stability studies should include testing of those attributes of the FPP that are susceptible to change during storage and are likely to influence quality, safety and/or efficacy. For instance, in case of tablets:

♦ appearance ♦ hardness ♦ friability ♦ moisture content ♦ dissolution time ♦ degradants♦ assay ♦ microbial purity


Selection of Batches At the time of submission data from stability studies

should be provided for batches of the same formulation and dosage form in the container closure system proposed for marketing.

Stability data on three primary batches are to be provided. The composition, batch size, batch number and manufacturing date of each of the stability batches should be documented and the certificate of analysis at batch release should be attached.

Where possible, batches of the FPP should be manufactured by using different batches of the API.


Evaluation – Variation, Trend A systematic approach should be adopted in the presentation

and evaluation of the stability information. Where the data show so little degradation and so little

variability that it is apparent from looking at the data that the requested shelf life will be granted, it is normally unnecessary to go through the formal statistical analysis; providing a justification for the omission should be sufficient.

An approach for analysing data on a quantitative attribute that is expected to change with time is to determine the time at which the 95% one-sided confidence limit for the mean curve intersects the (lower) acceptance criterion (95% assay).


Significant Change of FPPs A 5% change in assay from its initial value. Any degradation product exceeding its acceptance

criterion. Failure to meet the acceptance criteria for

appearance, physical attributes, and functionality test (e.g., colour, phase separation, hardness).

As appropriate for the dosage form, e.g., failure to meet the acceptance criteria for dissolution for 12 dosage units.


Evaluation – Best Case

1. Tabulate and plot stability data on all attributes at all storage conditions and evaluate each attribute separately.

2. No significant change at accelerated conditions within six (6) months.

3. Long-term data show little or no variability and little or no change over time.


Evaluation – Best Case4. Accelerated data show little or no variability

and little or no change over time.5. Statistical analysis is normally unnecessary.6. Proposed retest period or shelf life = double of

period covered by long-tem data (X) but NMT X + 12 months

7. A retest period or shelf life granted on the basis of extrapolation should always be verified by additional long-term stability data


ICH-Q1E Evaluation for Stability Data


Evaluation – Change with Time The hypothetical figure in the former slide

illustrates that the extrapolated shelf life is 29 months (25oC/60%RH) and there is only a 5% chance that this estimate will be high. Such a plot covers assay values from 105% down to 95%.

The majority of degradation processes results in an essentially linear line in this range of the label claim thus the method is generally applicable for the estimation of the expiry date at the studied storage conditions.


Carstensen, J.T. – Drug stability


Evaluation – Change with Time*The hypothetical figure in the former slide illustrates that the shelf life is 24 months (at a given temperature). There is a 5% chance that this estimate will be high. Such a plot covers potency values from 100% down to 90%.

* DRUG STABILITY — Principles and Practices

Edited by Jens T. Carstensen and C. T. RhodesThird edition, revised and expanded (2000)Marcel Dekker, Inc., 270 Madison Avenue, New York,


ICH-Q1E Evaluation for Stability Data


Evaluation – Change with Time The hypothetical figures in the former slides illustrate that

the shelf life is 31-32 months ( (25oC/60%RH) and there is only a 5% chance that this

estimate will be high. Such a plot covers degradant values from 0.6% up to 1.4%.

For FPPs in semipermeable containers, loss of vehicle can result in an increase in the API concentration. In such cases, the point where the upper 95% confidence bound intersects the 105% assay value will define the conformance period.


Additional or New Stability Data

Modifications affecting one or more steps

of the same route of synthesis of an API

Change in the route of synthesis of an API

Change in composition of the FPP

Change in immediate packaging of the FPP


Main points again Stability studies should be planned on the basis of

pharmaceutical R+D and regulatory requirements. Forced degradation studies reveal the intrinsic

chemical properties of the API, while formal stability studies establish the retest date.

The shelf life (expiry date) of FPPs is derived from formal stability studies.

Variability and time trends of stability data must be evaluated by the manufacturer in order to propose a retest date or expiry date.


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Workshop on Quality Assurance and GMP of Multisource HIV /AIDS medicines