analytical considerations drs. jan welink training workshop: assessment of interchangeable...

Analytical considerations

Drs. Jan Welink

Training workshop: Assessment of Interchangeable Multisource Medicines, Kenya, August 2009

Assessment of Interchangeable Multisource Medicines, Kenya, August 20092 |

GuidanceGuidance

FDA Guidance for Industry– Bioanalytical method validation, May 2001

ICH Guidance for industry– Validation of analytical methods: definitions and

terminology, June 1995 – Validation of analytical procedures: methodology,

November 1996


GCP/GLPGCP/GLP

GCP/GLP compliance– Clinical studies have to be performed under

conditions complying with the principles of Good Clinical Practice, and for analytical methods and sample data handling conditions complying with the principles of Good Laboratory Practice are required.

– For older studies without statement of compliance with the above mentioned principles, the assessor should rely on the quality of the submitted report.


Choice of methodChoice of method

Method used for the determination of drugs and/or metabolites should be:

SensitiveAccurateDiscriminativePrecise


SensitivitySensitivity

Method should be able to quantify the drug in the sampled specimen at least 10 % of the maximum concentration reached after dosing.

Limit of Quantification (LOQ): 1/10 Cmax


DiscriminativeDiscriminative

The method should be able to discriminate between the selected analyte and interfering compounds from the environment or from other compounds administered simultaneously


AccuracyAccuracy

The method must be accurate enough to measure the true value (concentration) of the analyte in a relative small sample


PrecisionPrecision

The analytical method should be precise enough to reveal identical results when the procedure is applied repeatedly to multiple aliquots of a single homogeneous volume of the biological matrix


ValidationValidation

To measure is to know!


ValidationValidation

Specificity

Detection limit (LOD)

Quantification limit (LOQ)

Linearity

Range

Accuracy

Precision

Robustness


Validation-specificityValidation-specificity

Investigation of specificity should be conducted during the validation phase of the assay

The procedures used to demonstrate specificity should be clearly reported

Must be applied with structurally similar materials

Choices base on scientific judgements


Validation-specificityValidation-specificity


Validation-LODValidation-LOD

Various methods possible

visual evaluation• minimum level at which the analyte can be

detected reliably

signal-to noise• 3:1 ratio is acceptable

standard deviation of the slope and response• LOD = 3.3 σ / S

– σ = standard deviation of the response– S = slope of the calibration curve


Validation-LOQValidation-LOQ

Based on signal-to noise– Reliable quantification is a 10:1 ratio

Based on SD of the response and the slope – LOQ = 10 σ / S

• σ = standard deviation of the response• S = slope of the calibration curve


LOQ, LOD and SNR

Limit of Quantitation

Limit of Detection

Signal to Noise Ratio

noise

Peak ALOD

Peak BLOQ

Baseline

Validation


Validation-LOD/LOQValidation-LOD/LOQ

Recommended data:

The LOD and LOQ and the method used for the LOQ should be presented

The limits should be validated by the analyses of a suitable number of samples prepared at the LOD and LOQ limits


Validation-linearityValidation-linearity

Should be evaluated across the range of concentrations expected during the study

A minimum of five concentrations used in the range is recommended

The correlation coefficient, y-intercept slope of the regression and residual sum of squares should be submitted

Deviations from the regression line should be analysed for evaluating linearity


Validation-linearityValidation-linearity


Validation-rangeValidation-range

The specified range is derived from linearity studies and should cover the extremes of the concentrations probably reached during the study

The range should be justified in the report based on scientific information


Validation-accuracyValidation-accuracy

Accuracy should be assessed on samples spiked with known amounts of the analyte

Accuracy should be assessed using determinations over a minimum of 3 concentration levels (low, medium and high)

Accuracy should be reported as percent recovery from the added amount


Validation-accuracyValidation-accuracy

LQC

MQC

HQC


Validation-precisionValidation-precision

Repeatability– concentrations covering the specified range

Intermediate precision– Like days, analysts, equipment

Reproducibility– Determined if analyses take place in separate periods


Validation-accuracy/precisionValidation-accuracy/precision

Accuracy/precision:



Intra-day:Between-day:


Validation-accuracy/precision:Validation-accuracy/precision:

Accuracy/precision calibrators:



FDA

Accuracy

within-run between-run

normally: <15%

LLOQ: <20%

Precision

within-run between-run

normally: <15%

LLOQ: <20%


Validation-robustnessValidation-robustness

Robustness should be considered during development phase

Shows the reliability of the analytical method with respect to variations in the method parameters

In case variations occur they should be suitably controlled and if present adequately tested and documented



Typical examples:

Stability of the analytical solutions– Influence of variations of pH of the mobile phase– Influence of variations of mobile phase

composition– Influence of temperature and flow rate

Extraction conditions– pH and extraction time


Validation-recoveryValidation-recovery

Recovery:

Extraction efficiency analytical method– consistent– precise– reproducible

Recovery:80%75%91%97%65%73%

mean: 81.1%

CV: 14.7%

Recovery:15%16%13%15%16%14%

mean: 14.8%

CV: 7.9%


Validation-stabilityValidation-stability

Required data – Freeze and thaw stability– Short term temperature stability– Long term stability– Stock solution stability– Post preparation stability

Stability assessed prior subject sample analysis!


Analysis clinical samplesAnalysis clinical samples

The analytical method should be validated before the start of obtaining clinical samples.

Each analytical run should contain sufficient QC samples at the beginning, middle and end at at least 3 levels (LQC, MQC and HQC).

QC QCQC QC QCQC



Acceptation or rejection of a run should be predefined before the actual start of the analysis of the clinical samples.

QC QCQC QC QCQC

FDA criteria



All samples of 1 subject in 1 run

Subject sample reanalysis should be predefined before the actual start of the analysis of the clinical samples.

QC QCQC QC QCQC

Reasons: -improper sample injection

-mail function -concentration > HLOQC

-unexpected value -PK reason



-unexpected value

-PK reason


ReportReport

All methods should be covered by adequate Standard Operating Procedures (SOP’s) for general and analysis specific procedures

Before the start of an analytical procedure an adequate study plan has to be written or be incorporated in the study protocol


ReportReport

A specific detailed description of the bioanalytical method should be written

All experiments used to make claims or draw conclusions should be presented in the report

GLP compliance/inspections/audits


EndEnd

analytical considerations drs. jan welink training workshop: assessment of interchangeable...

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