Residual solvent analysis of pharmaceutical products in accordance with the ICH Q3C guideline

Your needs : to reliably analyze residual solvents in your pharmaceutical products to meet the requirements stated by ICH Q3C

What is ICH Q3C ?

The ICH (International Conference on Harmonization) QC3 directive specifies the recommendations concerning acceptable toxicological concentrations of residual solvents (or residual volatile impurities) in pharmaceutical products to ensure the safety of patients.

ICH Q3C classifies residual solvents into three categories based on the toxicological risk they pose to humans :

Class 1 residual solvents : to be avoided

These solvents are carcinogenic (or at least suspected to be) for humans and pose a risk to the environment.

Class 2 residual solvents : for restricted use

These solvents are suspected to have severe but reversable toxic effects on humans.

Class 3 residual solvents : with low toxicity

What is a residual solvent according to ICH Q3C ?

Residual solvents in pharmaceutical products are defined as volatile organic compounds used in the manufacturing processes of pharmaceutical or medicinal products (benzene, acetone, cyclohexane, toluene, 1,4-dioxane…)

Residual solvents do not have any therapeutic benefits. However, an organic solvent can be used in pharmaceutical production processes to improve yield or to impose physicochemical properties on a substance or pharmaceutical product (ex. purity, crystallinity, solubility).

Consequently, finding these residual solvents in pharmaceutical products is possible, mostly because some techniques used in the manufacturing process do not completely eliminate these solvents.

How are residual solvents screened and quantified in pharmaceutical products ?

Residual solvents are usually isolated using separative techniques such as gas chromatography coupled with mass spectrometry (GC-MS). Harmonized methods such as those described in the American Pharmacopeia (USP 467)  must be used as much as possible to measure the concentration of residual solvents. If a different method is used it will first need to be properly verified.

The validation of analytical methods for residual solvents will be done in accordance with the directives specified in ICH Q2 documents (USP 467).

Regularly carrying out inspections makes it possible to avoid manufacturing incidents and to always be in line with changes in pharmaceutical specifications.

Our analytical services for ICG Q3C solvents

For over 30 years, out laboratory has had the experience and specific analytical fleet to be able to assists pharmaceutical companies with analysis of residual solvents in accordance with ICH Q3C guidelines, all while providing tailored support.

Assistance from a laboratory with expertise in the analysis of ICH QC3 solvents such as FILAB allows you to better overcome strategic challenges and changes in the field of pharmaceuticals.

FILAB laboratory assists pharmaceutical companies with research into residual solvents in pharmaceutical products and substances using GC-MS and HS-GC-MS equipment.

The positive aspects of FILAB

  • A highly qualified team

  • Responsiveness in responding to and processing requests

  • A complete analytical park of 2100m²

  • Tailor-made support

The ICH organization, also known as the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), serves as a platform for regulatory authorities and the pharmaceutical industry to collaborate on scientific and technical matters related to pharmaceuticals.


ICH's primary goal is to promote global harmonization within the pharmaceutical industry. By doing so, they aim to facilitate the development and registration of safe, effective, and high-quality pharmaceutical products in countries. This harmonization effort includes streamlining the resources necessary to bring these products to market while upholding stringent standards.


The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) develops a range of Quality Guidelines (Q1 to Q14) that cover various aspects of pharmaceutical development, including impurities, stability, and overall quality. One of these guidelines, ICH.Q3C, specifically addresses residual solvents and undergoes regular revisions.


It is crucial to stay up to date with these revisions, as residual solvents can have a significant impact on product quality. To ensure consistency and adherence to international standards, specifications for residual solvents ICH are established at the international level.


At the FILAB laboratory, we are proficient in the analytical methods required to accurately determine and measure the quantity of residual solvents in a sample. Our team of experts follows the acceptable health limits set by international professionals working within the ICH. Stay compliant and trust FILAB for accurate and reliable residual solvent testing.

- ICH Q3C indicates acceptable daily exposures (ADEs) for each residual solvents

- PDE, meaning Permitted Daily Exposure, are defined as pharmaceutically acceptable doses of residual solvents ICH

- Residual solvents are classified according to assessment of their potential risk to human health

Solvents, such as water, play a crucial role in the production of pharmaceutical drugs. However, the residual solvent presence can impact the safety, quality, and stability of the drugs. To ensure that residual solvent levels are kept to a minimum, it is necessary to conduct laboratory analysis. This analysis is a vital component of your drug registration file and is required to obtain market authorization.

Anaïs DECAUX Customer Support Manager
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