Method Development & Method Validation for Related Substance and Assay

Analytical methods are intended to establish the identity, purity, physical characteristics and potency of drugs. Methods are developed to support drug testing against specifications during manufacturing and quality release operations, as well as during long-term stability studies. Methods may also support safety and characterization studies or evaluations of drug performance. According to the International Conference on Harmonization (ICH), the most common types of analytical procedures are: (a) identification tests, (b) quantitative tests of the active moiety in samples of API or drug product or other select-ed component(s) in the drug product, (c) quantitative tests for impurity content, and (d) limits tests for the control of impurities.

The Source and Classification of Impurities

The related substances are systematically divided into organic impurities, inorganic impurities and residual solvents. Organic impurities may be generated during the production process and/or storage of new APIs. Organic impurities of APIs mainly include starting materials, intermediates, by-products, degradation products, reagents, ligands, catalysts, etc. Inorganic impurities are usually known to the production process and have been structurally identified. They include reagents, ligands, catalysts, heavy or other residual metals, inorganic salts, etc. Solvents are organic or inorganic liquids used as carriers for the preparation of solutions or suspensions during the synthesis of new APIs, and because they generally have known toxicity, they are controlled according to the residual solvent method. The possible degradation pathways in the preparation and the reaction with excipients and packaging containers will also produce impurities. In order to ensure the product quality is controllable, safe and effective, it is necessary to control the degradation impurities. Method validation is the process used to confirm that the analytical procedure employed for a specific test is suitable for its intended use. Results from method validation can be used to judge the quality, reliability and consistency of analytical results. It is an integral part of any good analytical practice.

Method Development and Method Validation Process

A systematic method development and validation strategy is to utilize better experimental design and follow the following process for efficient, high-quality analytical method development. Method validation for a substance is to demonstrate that the analytical method is suitable for its intended purpose. Method development and method validation process is as follows.

Method Development and Method Validation Process

Our Services

CD Formulation, as a professional drug formulation development provider, offers a series of drug analysis and testing services, including the determination of physical constants, bio-assays, impurity analysis, stability testing and method validation and development services, which help customers to know enough specific information about drugs for better drug development and accelerate the process of drug commercialization.

Why Choose CD Formulation?

CD Formulation has provides full service method development and method validation for our customers based on decades of industry experience. From initial research including separation mode selection, stationary phase selection, mobile phase selection through to lifestyle method improvements, we work closely with customers to produce methods which meet or exceed their analytical needs. Based on the company's advanced testing equipment and perfect quality management system, it can help the project team to complete the development and methodological verification of analytical methods for APIs and preparations.

How to Contact us?

If you have a requirement about our services, please contact us by phone or email, our colleagues will reply to you within three working days.


  1. ICH Q2(R2): Validation of a analytical procedures.
  2. ICH Q3A(R2): Impurities in New Drug Substances.
  3. ICH Q3B(R2): Impurities in New Drug Products.
  4. USP 1225: Validation of compendial procedures
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