Residual Solvents
ICH Q3C Impurities: Residual Solvents
Contract Laboratories Perspectives
Assad J. Kazeminy, Ph.D.
President and CEO of Irvine Analytical Laboratories, Inc.
Residual Solvents
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This Session will address the implementation of ICH Residual
Solvents requirements by USP and PhEur from perspective of CRO:
¾ Solvent Classification
¾ Interaction between Laboratory and API Manufacturer
¾ Selection of Methodologies
Screening methodologies
™ Method Validation
™ Routine vs. Qualification testing
¾ Past Chromatographic Challenges
¾ Case Studies
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Introduction
• Residual solvents have had official limits in the United States as
set in USP 30 <467> and by the FDA in 1997 and have been
monitored by most pharmaceutical manufacturers extensively for
more than two decades in both bulk and finished products.
• Residual process solvents in pharmaceutical samples are monitored
using gas chromatography (GC) with either flame ionization
detection (FID) or mass spectrometry. Based on good
manufacturing practices, measuring residual solvents is mandatory
for the release testing of all active pharmaceutical ingredients and
is routinely performed on samples of process intermediates.
• On Jan 1, 2007 title of Chapter <467> will be changed to Residual
Solvents.
Introduction
z Sample introduction techniques include both static and dynamic
headspace analysis, solid-phase microextraction, and direct injection of
solution containing bulk drug substance or drug product into the gas
chromatograph.
z In conclusion, gas chromatograph-based procedures will continue to
dominate residual solvent testing because of its specificity for
identification of the solvent, but the use of alternative sample introduction
techniques into a gas chromatograph will continue to expand in the near
future.
Classification of Residual Solvents by Risk
Assessment
Solvents were evaluated for their possible risk to human health and placed into
one of three classes as follows:
Class 1 solvents: Solvents to be avoidedKnown human carcinogens, strongly suspected human carcinogens, and
environmental hazards.
Class 2 solvents: Solvents to be limitedNongenotoxic animal carcinogens or possible causative agents of other
irreversible toxicity such as neurotoxicity or teratogenicity. Solvents
suspected of other significant but reversible toxicities.
Class 3 solvents: Solvents with low toxic potentialSolvents with low toxic potential to man; no health-based exposure limit is
needed. Class 3 solvents have PDE's of 50 milligrams (mg) or more per day
Interaction between CRO and Sponsor
In order to launch and complete studies successfully the following steps
are recommended:
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Project Initiation
Provide CRO with DMF information and/or Physico/Chemical properties
of the API
Provide limits for each known residual solvent to CRO if Testing Drug
Product (Based on TDI)
Agree on choice of technology to be utilized in support of testing (GCFID or GC/MS)
Is prescreening required?
API Qualification or routine Testing?
Method Validation Scope
Interaction between CRO and Sponsor
•
•
Method Transfer
™ CRO required to review validation report
™ Feasibility
™ Write protocol
™ Generally, selectivity, LOD/LOQ and Repeatability
™ CRO will provide Final report for review and approval
Routine Analysis
™ Always start with USP <467> procedure A
™ Upon completion of studies CRO will provide C of A and Raw data if
deemed necessary.
Interaction between CRO and Sponsor
•
•
•
•
Screening Method
It is recommended to perform chromatographic profile for API which
residual solvent are not known and/or their respective limits are not
known.
Generally GC/MS equipped with Head Space analyzer is
recommended
• Due to its greater sensitivity
• Greater selectivity
In addition to chromatographic profile, following studies need to be
evaluated:
• LOD/LOQ
• Repeatability
Interaction between CRO and Sponsor
•
Follow USP Procedure A
• If peak response of any peak in Test solution is ≥ to either peak in
Class I and or Class II proceed to procedure B for ID
• Follow USP Procedure C for accurate quantitation of known
residual solvents
Interaction between CRO and Sponsor
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Method Validation
Upon completion of screening method, the method needs to be Validated as
follow:
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Selectivity
Linearity from LOQ to 120% of specified limit for each solvent
LOD/LOQ for standards and Spiked sample
Repeatability
Intermediate Precision
Accuracy: 80 to 120% of each solvent
Robustness
•
•
GC
Head Space
Interaction between CRO and Sponsor
Qualification of API
™
Qualify each API by evaluating 3 consecutive lots of API
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If multiple vendors of API are available, perform repeatability in triplicate
preparation for each vendor
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This work is performed only once
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Upon completion of API qualification, test future lots by analyzing samples in
triplicate preparation
Interaction between CRO and Sponsor
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Routine API Testing
Perform Routing Testing as follow:
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Chromatographic non-interference
LOD/LOQ
System Suitability
Bracketing Standards
Sample (n=3)
Blank
Bracketing Standard
Selection of Methodologies
•
•
•
To determine Residual Solvents, many quality-control labs in
pharmaceutical manufacturing employ GC-FID for the determination
of residual solvents that are included in either USP <467> or ICH
guidelines.
Because some of the solvents co-elute, these labs must use at least two
different separation phases. Co-elution is not a problem with mass
spectrometric detection, as most co-eluting analytes have unique ions.
The mass spectrometer also provides a means to identify unknown or
unexpected contaminants.
With the 5975 inert Mass Selective Detector (MSD), a single analysis
provides both selected ion monitoring (SIM) for sensitive quantitation
and full-scan spectra for identification of unknowns.
Selection of Methodologies
•
According to published list in ICH Q3C , there are 61
solvents.
•
This list would be a challenge for separation on any single
GC phase , as critical coelution will be inevitable.
•
In ICH guideline, residual solvents are grouped based on
their toxicity, both class I and class 2 need to be analyzed
by sensitive and specific methodologies. However, class 3
could be assayed by non-specific techniques, such as
weight loss on drying <731>, due to their low toxicity.
Selection of Methodologies
•
Due to the advance in head space technology-mainly dynamic
sampling techniques, and dual column capability faster analysis, better
sensitivity and specificity is possible (MACH system allows up to 4
columns).
•
Restek group has reported separation of 23 residual solvents in 8 min
by utilizing dual column separation on MACH system. MACH is an
Agilent GC 6890 equipped with Gerstel Modular Accelerated Column
Heater (MACH)
Figure 1. Agilent GC/MS equipped with Head Space Analyzer
Agilent Technologies, 6890N Network GC system,
MS: Agilent Technologies, 5975 inert XL Mass Selective Detector
Data aAnalysis: Software: G1701DA ChemStation,
Figure 2.
CTC Autosampler System for Headspace and Liquid Injection.
Past Challenges 1
USP OVI Method IV for Class II Solvents
¾
Two early eluting extraneous peaks were detected on sample chromatogram.
¾
Upon laboratory investigation it was determined that these two peaks were
reproducible and are process Solvents from API.
¾
In API Technical Package there was no information about those two Unknown
peaks.
¾
Further investigation is pending .
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Past Challenges 1
USP OVI Method IV for Class II Solvents
Chromatogram 1
Unknown Peaks
Methylene Chloride
Trichloromethene
Sample
Chloroform
1,4-Dioxane
Standard
Past Challenges 2
USP OVI Method IV for Class II Solvents
¾
One Late eluting extraneous peak was detected on sample chromatogram.
¾
Laboratory Investigation suggested that Unknown peak is present in every
sample preparation of API (Same Lot).
¾
In API Technical Package there was no information about this Unknown
peak.
¾
Further investigation is pending
Past Challenges 2
USP OVI Method IV for Class II Solvents
Chromatogram 2
Methylene Chloride
Trichloromethene
Unkown Peak
Chloroform
Sample
1,4-Dioxane Standard
Past Challenges III
USP OVI Method I for Class II Solvents
¾
One early eluting extraneous peak was detected on sample chromatogram.
¾
Laboratory Investigation suggested that Unknown peak is present in every
sample preparation of API (Same Lot).
¾
In API Technical Package there was no information about this Unknown
peak.
¾
No attempt was made for Identification of Unknown peak.
Past Challenges 3
USP OVI Method IV for Class II Solvents
Chromatogram 3
Methylene Chloride
1,4-Dioxane
Methylene Chloride
Trichloroethylene
Chloroform
Standard
Unknown Peak
Sample
Chloroform
Chloroform
Past Challenges
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Lesson Learned
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Perform API Screening by Utilizing GC/MS
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Ask for DMF
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Qualify your API
Published Methodologies in USP
Procedure A (Profiling) for Water-Soluble Article
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Class 1 and Class 2 residual Solvents
–
Chromatographic Conditions:
Column: 0.32mm x 30 m fused-silica column coated with 1.8 μm layer of
G43 or 0.53 mm x 30m wide-bore column coated with 3.0 μm layer of G43
Carrier: He or N2 with linear velocity of 35 cm/sec and split ratio of 1:5
Column temperature: 50 °C –
6 °C /min--165 °C hold for 20 min
Injection port: 140 °C
Detector Temperature: FID @ 250 °C
Method of Injection: Static Head Space
Note: USP Residual Solvent standards are available
Published Methodologies in USP
Procedure B (Peak ID)
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Class 1 and Class 2 Residual Solvents
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Chromatographic Conditions:
GC-FID
Column: 0.32mm x 30 m fused-silica column coated with 0.25 μm layer of
G16 or 0.53 mm x 30m wide-bore column coated with 0.25 μm layer of G16
Carrier: He or N2 with linear velocity of 35 cm/sec and split ratio of 1:5
Column temperature: 40 °C –10 °C /min--240 °C
Injection port: 140 °C
Detector Temperature: 250 °C
Method of Injection: Static Head Space
Published Methodologies in USP
Procedure C
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Class 1 and Class 2 Residual Solvents for Water-Soluble Article
• Follow Procedure A or B for Quantification of each Residual Solvent
• Injection Sequence is as follows:
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Blank
System Suitability
Standard Solution
Test Solution
Spiked Test Solution
Standard Solution
Screening Method
•
•
•
•
It is recommended to perform chromatographic profile for API which residual
solvents are not known and/or their respective limits are not known
Generally GC/MS equipped with Head Space analyzer is recommended
• Due to its greater sensitivity
• Greater selectivity
In addition to chromatographic profile, following studies need to be evaluated:
• LOD/LOQ
• Repeatability
Follow USP Procedure A
• If peak response of any peak in Test solution is ≥ to either peak in Class I
and or Class II proceed to procedure B for ID and
• Follow USP Procedure C for accurate quantitation of known residual
solvents
Case Study I : Class I Solvents Incubation Time
Objective: To assess affect of incubation time on recovery of Class I
solvents in water soluble Matrix.
Methodology:
Instrument: Agilent GC-FID equipped with Headspace Analyzer
Column: Phenomenex ZB-624, 30 m x 0.53 mm, 3μm
Temperature program: 40°C for 20 min -----50°C/min to 240°C
Injection Port Temp.: 140°C
Head Space Parameter: 80°C for 30, 45 and 60 min
Injection Volume: 1 ml
Case Study I : Class I Solvents Incubation Time
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Graph 1
1,2-DCA
60min
TCE
45min
30min
Benzene
0
500
1000
1500
2000
2500
3000
3500
Peak Area
Case Study I : Class I Solvents Incubation Time
Conclusion:
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Incubation time had minimum effect on each residual solvent recovery.
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However, it is highly recommended to consider conducting robustness
studies on critical GC and Head Space parameters.
Case Study II : Screening Method For Class II Solvents
Objective : To evaluate a Screening method for water soluble Class II solvents
Scope of the Work: Selectivity, LOD/LOQ, System Suitability and Repeatability
Case Study II : Screening Method For Class II Solvents,
Results
Blue: Spike sample
Red: Blank
Green: Unspike Sample
Trichloromethene
Methylene Chloride
Toluene
Case Study III : DMSO Selection for Non-Aqueous
Soluble API
z
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Objective: To evaluate chromatographic profile of various DMSO
Scope: Selectivity of method for non –Aqueous soluble API was assessed by
utilization of different grades of DMSO as diluent
– Method: GC/FID equipped with Head Space Analyzer
– Column: ZB 624, 30 m x 0.53 mm, 3 μm (USP G43)
Case Study III : DMSO Selection for Non-Aqueous
Soluble API
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Results
DMSO A (Blank)
DMSO A with Sample
Case Study III : DMSO Selection for Non-Aqueous
Soluble API
DMSO B (Blank)
DMSO B with Sample
Case Study III : DMSO Selection for Non-Aqueous
Soluble API
DMSO C (Blank)
DMSO C with Sample
Summary
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Review API DMF or Technical Package
Perform Screening of API
Qualify API
Acknowledgement
Ruggero Pocci
David Pride
Hamid Forouhar
Mai Zhang,PhD
GC Group Leader
GC Scientist
QC manager
Sr. Scientist