How to Design a Leachables and Extractables Study

Background Information

Materials of Construction

What additives are used?
Multilayer films?
Printing Inks?

Finished Packaging

Which surfaces does the product contact?
Are there interactions between components?
Is there opportunity for non-product contact components to migrate?
Are there any processing aids used?

Use Conditions

Extractables

Challenge the use condition

  • Temperature
  • Solvent Strength
  • Time

Leachables

Mimic the most stringent use condition

Extraction Strategies

Cut and Cover Extraction

  • Simple systems
  • Irregularly shaped
    • Articles requiring two-sided extraction
  • Very large containers

Full Fill Extraction

  • Bags
  • Small containers
  • Tubing
  • Non-permeable
  • Printed containers

One-Sided Extraction

Multi-layer

  • Printed materials
  • Coated materials
  • Product contacts one side

Flow Through Extraction

Tubing

  • Complex systems
  • In-Line filters
  • Connectors

Large Volume Dynamic Headspace

  • Direct analysis of the entire article
  • Very high sensitivity
  • No risk of volatiles loss

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Extraction Solvent

From the background information provided for a container closure system the probable extractables were:

Expected Extractable Type Log P Boiling point
Erucamide Hydrophobic 8.8 474 °C
Linear Alkanes Hydrophobic 8.859 250-400 °C
Dibutylphthalate Hydrophobic 4.72 340 °C
Dimethoxyethane Volatile -0.2 85 °C
Irganox 1010 Non-volatile 23 N/A
Irgafos 168 Non-volatile 15.5 N/A
Tinuvin 770 Basic 6.3 N/A
Stearic acid Acidic 8.23 361 °C
Sodium benzenesulfonate Anionic N/A N/A

 

Effect of Solvent Polarity

Agilent 1290 Infinity UHPLC; Agilent 6520 QTOF-MS
Column: Agilent Zorbax Eclipse Plus C8; 1.8 µm, 2.1x50 mm
Electrospray IonizaAon (ESI); Polarity: positive

Extract Preparation

Example:

  • 250 mL per bag
  • Worst case 3 bags per day
  • Product contact surface area 310 cm2
  • Safety concern threshold (SCT) = 0.15 µg/day

AET (µg/bag) = 0.15 µg/day/3 bags/day = 0.05 µg/bag

Extract Vol. (mL) = 310 cm↑2/6 cm↑2/mL =52 mL

LOD = 0.05 µg/bag / 52 mL/bag ≈ 1 ng/mL

Qualitative Analysis

Concentration of Extracts

Extractables and Leachables can be lost during concentration

Loss depends on

  • Volatility of the analyte(s)
  • Extract handling

Best Practices

  • Mild conditions
  • Method validation
  • Headspace analysis

Qualitative Analysis

No universal analytical technique exists for E&L analysis

  • Headspace GCMS
    • Volatiles
  • QTOF-GCMS
    • Volatiles
    • Semi-Volatiles
    • Non-polar analytes
  • QTOF-LCMS
    • Polar/ionizable
  • ICP-MS
    • Metals

Extraction Conditions

Ethanol Extract

Expected Extractables Type Log P Boiling point
Erucamide Hydrophobic 8.8 474 °C
Linear Alkanes Hydrophobic 8.859 250-400 °C
Dibutylphthalate Hydrophobic 4.72 340 °C
Dimethoxyethane Volatile -0.2 85 °C
Irganox 1010 Non-volatile 23 N/A
Irgafos 168 Non-volatile 15.5 N/A
Tinuvin 770 Basic 6.3 N/A
Stearic acid Acidic 8.23 361 °C
Sodium benzenesulfonate Anionic N/A N/A

 

Qualitative Analysis

Agilent 1290 Infinity UHPLC; Agilent 6520 QTOF-MS
Column: Agilent Zorbax Eclipse Plus C8; 1.8 µm, 2.1x50 mm
Electrospray Ionization (ESI)

Agilent 7890B GC; Agilent 7200 QTOF-MS
Column: DB-5MS UI; 0.25 mm x 30 m, 0.25 µm
Electron Impact Ionization

Agilent 6890 GC; Agilent 5973 inert MSD
Electron Impact Ionization

Identification of Unknowns

Database Searches

  • Commercial Databases (NIST, Wiley)
  • Jordi Proprietary Additive and Oligomer Databases

QTOF-GC/QTOF-LC

  • Molecular Formula Generation (MFG)
  • MS/MS for QTOF -LCMS
  • CI for QTOF-GCMS

m/z Best Match Species Mass Score (MFG) Diff. (ppm) DBE
274.2731 C16 H35 N O2 [M+H]+ 273.2660 94.66 2.73 0

 

Quantitative Strategies

Relative Quantitation

  • Quantification of compounds observed is carried out against surrogate standards
  • Accuracy is based on the surrogate standard used

Estimated Analyte Conc. = Observed Analyte Peak Area / Surrogate Peak Area x Surrogate Conc.

Formal Quantitation

Confirmed compounds are quantified against an analytical standard at a series of concentrations

Methodologies:

  • External Standardization
  • Standard Addition
  • Needs high purity analytical standards

Quantitative Method Development

Quantitative Methods:

  • Dynamic Headspace GCMS
  • UHPLC-UV
  • UHPLC-CAD
  • QTOF-GCMS

In formal quantitation limit of quantitation (LOQ) can be improved using:

  • Targeted MS/MS
  • Large Volume Injection

Agilent 1290 Infinity UHPLC
Column: Zorbax SB-C18, 1.8 µm, 100 x 2.1 mm
Mobile Phase: H2O – ACN Grad.
Detection: 230 nm (DAD)

2D UHPLC

Quantitative Method Development

Column: Zorbax SB-C18; 1.8 µm, 2.1x50 mm
Mobile Phase: H2O – ACN Gradient
Detection: 230 nm (VWD)
Collection Mode: Heart-cutting; 2.18-2.22 minutes (40 µL)

Column: Eclipse Plus Phenyl-Hexyl; 1.8 µm, 2.1x50 mm
Mobile Phase: H2O – ACN Isocratic
Detection: 230 nm (DAD)

Column: Eclipse Plus Phenyl-Hexyl; 1.8 µm, 2.1x50 mm
Mobile Phase: H2O – ACN Isocratic
Detection: Fluorescence; 225 nm excitation, 310 nm emission

A successful study has:

  1. Definitive identifications
  2. Accurate quantification
  3. Appropriate extraction conditions
  4. Careful concentration of extracts

This information has been sourced, reviewed and adapted from materials provided by Jordi Labs.

For more information on this source, please visit Jordi Labs.

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Comments

  1. Imad Nour Imad Nour United States says:

    How to calculate AET for hose used to deliver pharmaceutical solution to the tank after compounding.

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