Elemental Impurities Testing:

Its Role in Compliance,

Analysis Components,

and Industry Collaboration around

Technical Challenges

Donna Seibert, PhD

on behalf of the

Technical and Analytical Challenges Sub-team

to the Coalition for Rational Implementation

AAPS

October 27, 2015

EI Risk Assessment Components • Model on ICH Q3D

– Illustrative examples in Appendix 4

– Scientifically sound assessment of risk

• Product Information

– Identify raw materials and weight percent in formulation

– Identify maximum daily dose and route of administration

• Documentation Review

– Sources of raw materials and related risks

– Intentionally added elements

– Potential elements from manufacturing and container closure

• Data

– Raw material or finished product

– Example: 1-6 lots of raw materials or finished products depending on

pre-assessment of risk

• Manufacturing, container closure, water

– Data

– Position papers??

2

• Literature

• Supplier Information

• Pooled Data

Fit for Purpose Methods

• Risk Assessment

– Screening methods

– Wide range of elements

• General screen (15-24 EIs)

• Target elements of interest

– Quantitative or semi-quantitative

– Typically not fully validated

3

• Formal Control

– Limit tests or quantitative tests

– Specific elements in specific products or materials

– Fully validated

– Methods & validation reports included in NDA/ANDA

filings

Elemental Impurities Testing

Challenging Terrain

• Key challenge for industry and the regulatory community

– Analytical testing required to quantitate elemental impurities in drug products, APIs and excipients down to the levels listed in USP <232> and/or ICH Q3D guideline.

• Variety and complexity of pharmaceutical samples

• Many labs expanding capabilities

– Pharmaceutical labs adapting to ICP-MS analysis

– Existing spectroscopy labs adapting to the requirements of <233>

• Technical/Analytical Challenges Project Team formed in 2013 as a sub-team of the Coalition for Rational Implementation

TECHNICAL/ANALYTICAL CHALLENGES PROJECT TEAM

Sub-Team Objectives:

• Communicate the complexity of ICP/MS methodology (including,

as appropriate, difficult and/or hazardous sample preparation

studies) and portray a realistic picture of the technique for the

benefit of industrial partners as they build expertise in elemental

impurities analysis

• Compile, elucidate, and bring visibility to technical and analytical

challenges that RM suppliers and FP manufacturers are facing

during implementation of USP/ICH Elemental Impurities controls.

• Bring industrial, regulatory, and academic partners together to

propose solutions to analytical challenges wherever possible.

5

TECHNICAL/ANALYTICAL CHALLENGES PROJECT TEAM

Team Chartered June 2013

Membership (42+ colleagues)

• Comprised of scientists from

– Coalition companies

• 5 pharmaceutical companies

• 7 raw material suppliers (API/excipient)

– 8 Contract laboratories

– 1 Government laboratory

– 1 University laboratory

Analytical Testing Considerations

• Sample Preparation

– Ensure appropriate solution preparation

– USP <233> suggests

• neat solution

• direct solution (aqueous or organic)

• indirect solution via closed vessel (microwave assisted)

• Instrumental Analysis

– System suitability/data integrity

– Options for sample introduction and interference reduction

– Data interpretation

7

Total Metal Extraction vs.

Acid Leach Methodology

8

Total Impurities = present in any form

Bioaccessible = soluble in digestive juices

Bioavailable = reach systemic circulation

Total Impurities ≥ Bioaccessible ≥ Bioavailable

“Total metal extraction is the preferred sample preparation approach

to obtain an indirect solution.” 2S (USP38)

“Alternatively, leachate extraction may be appropriate with justification

following scientifically validated metal disposition studies, which may

include animal studies, speciation, or other means of studying

disposition of the specific metal in the drug product.” 2S (USP38)

Courtesy: F. Walker, Chemical Solutions

Total Metal Extraction vs.

Acid Leach Methodology

Acid Leach methodologies

– Intended to assess bioaccessible or bioavailable levels of elemental

impurities in a material

– Typically use less aggressive conditions—heating blocks, shakers,

rotators

– Often used in environmental and food industries

– Allowed by USP <233> with supporting data

9

Courtesy: F. Walker, Chemical Solutions

Total Metal Extraction vs.

Acid Leach Methodology

Total Metal Extraction

– Not defined in USP <233>

– Intended to analyze all elemental impurities contained in the sample? Or

all that can be extracted?

– Typically use aggressive condition

– Requirement for full dissolution of the sample matrix resulting in a clear

solution

• Not explicitly stated in USP <233>

• Required by EP 2.4.20

10

Example Microwave Digestion Conditions

With HF

Load

–0.25 grams of sample

–1.5 mL 70% HNO3

–1.5 mL 49% HF

Heat

–30 minute ramp to 250 °C

–20 minutes @ 250 °C

Dilute

–to 20 mL with DI water

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Default Digestion

Load

–0.25 grams of sample

–3.0 mL 70% HNO3

–0.5 mL 37% HCl

–3.0 mL 30% H2O2

Heat

–15 minute ramp to 140 °C

–5 minutes @ 140 °C

–10 minute ramp to 240 °C

–10 minutes @ 240 °C

Dilute

–to 50 mL with DI water

ICP/MS Analysis

• Prepare Instrument for Analysis

– Daily performance checks

– Plasma alignment, MS tuning, etc.

• Sample Introduction & Instrument Parameters

– Accessories, reaction gasses & collision cells

• Interference reduction

– Internal standards

• Selected by isotopic mass or ionization potential

– Correction equations

• Calibration & LOQ

– Blank, 0.5J and 1.5J calibration standards (minimally)

– Multiple sets of standards may be needed to cover required elements

– LOQ can be a concern

• For some finished products (e.g., liquid products with large MDDs)

• When analyzing raw materials

Typical Sequence Including

System Suitability & Calibration

13

Solution Purpose/Description Requirement

Calibration Standards (5 + blank) Establish Curve r2 NLT 0.99

ICV (Initial Calibration Verification) Midpoint Std Readback w/i 80-120% of theor. conc.

ICB (Initial Calibration Blank) Carryover Check below lowest calibration std

Samples (max 10)

Preparation Blank below lowest calibration std

LCS (Lab Control Sample) Digested, spiked blank w/i 70-150% of theor. conc.

Sample (1)

Pre-digestion Spike (PDS, 1) Matrix spike w/I 70-150% after subtraction of

indigenous EIs

Remaining Samples (2-4) + PDS

CCV (Continuing Calibration Verification) Midpoint Std Readback w/i 80-120% of theor. conc.

CCB (Continuing Calibration Blank) Carryover Check below lowest calibration std

Remaining Samples & CCV/CCB

Data Interpretation

Data review

• Recognition of issues

– Instrument drift

– Carryover/memory effects

– Interferences or element-specific pitfalls

– Non-ideal recoveries

• Reportable data

– Use of multiple modes and/or reaction gasses possible

– Can require data selection

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Analytical Considerations—Conclusions

• Clearly define goal of testing

– Screening for risk assessment or formal control

• Clearly define type of digestion

– Total metal extraction or acid leach

• Understand materials and how matrix can affect analysis

– Dissolved solids, undigested carbon, etc.

• Get to know your analyst!

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Inter-laboratory Collaborative Study Overview

OBJECTIVES:

To provide a DATA-DRIVEN way to discuss technical aspects

of ICP-MS testing for elemental impurities

• Inter-laboratory data comparison for standardized samples

• Inter-laboratory evaluation of effectiveness of microwave digestion

• Compare bio-relevant leach/extraction techniques to total metal

extraction

• Determine the correlation (good or bad) between the summation of

individual component results vs. testing the formulated tablet

PARTICIPANTS:

• 13 member laboratories participated in the collaborative study

• Blinded participation was a pre-requisite for several laboratories

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Inter-laboratory Collaborative Study Overview

SAMPLES:

• Two Treatment Groups

• Group A Tablets contained native EI levels originating from

excipients

• Group B Tablets were spiked with ICH Class 1 & 2A elements

• As, Cd, Pb, Hg, Mo, Co, Se, V

• Tablets designed with an intended MDD of 1 g, so that material

concentration (ug/g) and ICH limit (ug/day) could be plotted on the

same scale

METHODS:

• Uniform method—a defined set conditions intended to be run at

each lab

• Non-uniform methods—methods of choice for participating labs

Uniform Digestion—Arsenic

Mean (ppm): 0.57 1.47

STD: 0.98 0.91

RSD (%): 172 62

ND values: 12 0

Native Enhanced

Blue points are below LOQ,

Error bars set at 1.5 x Interquartile Range

o Open circles indicate outliers

Uniform Digestion—Lead

Mean (ppm): 1.07 3.12

STD: 0.35 0.75

RSD (%) 33 24

ND values: 3 1

Native Enhanced

Blue points are below LOQ,

Error bars set at 1.5 x Interquartile Range

o Open circles indicate outliers

Data Refinement—Lead by Uniform Digestion

Original

07-Jan-2015

Updated

05-Mar-2015

• Orange data points indicate outliers o Open circles indicate outliers

pp

m

Error bars set at 1.5 x Interquartile Range

Data Refinement—Lead by Uniform Digestion

Original

07-Jan-2015

Updated

05-Mar-2015

• Orange data points indicate outliers o Open circles indicate outliers

pp

m

Error bars set at 1.5 x Interquartile Range

Labs benefit from having comparator samples

Summary Statistics—All Methods

Element Mean

(ppm) STD RSD

(%)

As 0.16 0.05 33.94

Cd 0.02 0.04 204.28

Pb 0.88 0.14 15.37

Hg 0.06 0.07 116.52

Co 0.23 0.19 84.48

Mo 0.09 0.14 161.22

Se 0.16 0.22 137.59

V 0.85 0.50 58.57

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Element Target

(ppm) Mean

(ppm) STD RSD

(%)

As 1.77 1.25 0.27 21.65

Cd 0.38 0.36 0.06 15.78

Pb 1.58 2.87 0.38 13.27

Hg 1.30 0.31 0.09 27.95

Co 1.62 0.75 0.08 11.30

Mo 0.72 1.38 0.50 36.29

Se 1.46 0.59 0.48 80.68

V 3.10 2.14 0.40 18.80

Non-uniform, Native Levels Non-uniform, Enhanced Levels

Element Mean

(ppm) STD RSD

(%)

As 0.57 0.98 171.55

Cd 0.01 0.03 195.67

Pb 1.07 0.35 32.60

Hg 0.47 1.68 360.71

Co 0.17 0.03 18.39

Mo 0.17 0.22 134.02

Se 0.23 0.33 142.98

V 1.91 1.98 103.41

Element Target

(ppm) Mean

(ppm) STD RSD

(%)

As 1.77 1.47 0.91 61.84

Cd 0.38 0.38 0.13 33.40

Pb 1.62 3.12 0.75 24.00

Hg 1.30 0.37 0.17 46.00

Co 0.72 0.67 0.19 28.67

Mo 1.58 1.47 0.41 28.02

Se 1.46 0.57 0.38 66.39

V 3.10 2.67 1.69 63.15

Uniform, Native Levels Uniform, Enhanced Levels

Non-Uniform Methods using HF—Lead Results

• 6 HF methods vs. uniform

digestions

• Limited ability to generate clear

digestates (total digestion)

• No discernable increase in

extraction of Pb from tablets with

native levels

23

Native

pp

m

Non-Uniform Methods using HF—Lead Results

• 6 HF methods vs. uniform

digestions

• Limited ability to generate clear

digestates (total digestion)

• No discernable increase in

extraction of Pb from tablets with

native levels

24

Native

Use of HF does not guarantee clear digestate or “total” digestion

pp

m

RM Summation vs. Tablet Testing

(Native Levels, Uniform Digestion) • Outliers highly affected means for finished product analysis

(16.8% of all reported values were classified as outliers)

Raw Materials Analysis

Finished Product Analysis

Outlier Analysis

Through calculation of Odds Ratios:

• Tablet Type

– Tablets with native levels and those with enhanced levels of were not

distinguishable in frequency of outliers

• Microwave Type

– Individually pressurized vessels (IPV) vs. single reaction chamber (SRC)

systems showed that IPV systems are 6.7 times more likely to produce

outliers than SRC systems

• Correction Equations

– Use of correction equations for certain elements reduced the odds of

producing outliers by 7.7 times

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Data Overview

• All elements across all labs

• Statistical analyses* indicate

that the variability for each

element across labs is

significantly higher with the

uniform method than the

non-uniform method

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* Measurement Systems Analysis and Assessment of Variability

Native Enhanced

Data Overview

• All elements across all labs

• Statistical analyses* indicate

that the variability for each

element across labs is

significantly higher with the

uniform method than the

non-uniform method

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* Measurement Systems Analysis and Assessment of Variability

Labs perform best when methodology is optimized for their instrumentation

Native Enhanced

Inter-Laboratory Study Conclusions

• Data for standardized samples show high variation across

laboratories

• Labs benefit from access to standardized evaluation samples

• Comparison of summation approach and finished product testing is

confounded by low levels of native elements and high influence of

outliers

• Outlier analysis shows that microwave type may affect results and

use of correction equations is beneficial for some elements

• Tighter variation among non-uniform methods suggests need for

flexibility in methodology for testing labs

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On-going and Future Work

• Publication of Phase I results

– Drafted

• XRF investigation on existing tablets (4 participating labs)

– Experimental planning and material distribution complete

– Sample testing is in progress

• Phase II testing

– Build on results and learnings from Phase I

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Phase II Inter-Laboratory Study

To include:

• New tablets containing higher native EI levels

– Need to ensure that formulation remains realistic & compressible

– Spike with updated ICH Class 1 & 2A elements

• Refinement of test protocols

– Ensure adequate data around HF vs. non-HF methods

– Ensure adequate data around acid leach vs. total digestion methods

– Distribute raw materials to a larger number of labs

– Define procedures around LOQs and LODs

– More carefully consider use of reaction gases/KED, internal standards,

and correction equations

• Refinement of reporting templates

– To streamline data analysis

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Study Participants and Acknowledgements AQura Cornel Venzago

Chemical Solutions Francine Walker

ColorCon Gary Hayes

Dow Corning Jason Sturm

ELS Brendan Murray

JM Huber Hal Garber, John Offidani

Liverpool John Moores Univ. Phil Riby

Perrigo James Bennett, Andy Kampfschulte, Josh Foote,

Rob Lievense, Matt Schmitt, Saul Gylys

Pfizer Sam Powell, Nikki Clements

P&G Denise McClenathan, Roy Dobson, Andrei Shauchuk

RTI James Harrington

Solvias Gisela Fontaine, Josephine Archinal

US Geological Survey Ruth Wolf

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…and all other TAC Team members, Thank You!!!