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Related substances and Impurities


مساء الخير يا دكاتره 

ممكن حد يعرفني what the different between related substances and Impurities in raw materials .... 

وياريت لو حد يعرف داتا كويسه افهم منها موضوع related and impurities  اكون شاكر له

1 Answer
Best Answer

Briefly; Impurities are the main huge tree! while related substances are considered branch of that tree.

A good guidance is ICH Q3A.

 In details; according to ICH Q3A; Impurities can be classified into the following categories:

 Organic impurities (process- and drug-related; related substances)

 Inorganic impurities

 Residual solvents

Organic impurities can arise during the manufacturing process and/or storage of the drug substance. They can be identified or unidentified, volatile or non-volatile, and include:

- Starting materials

- By-products

- Intermediates

- Degradation products

- Reagents, ligands and catalysts

Inorganic impurities can result from the manufacturing process. They are normally known and identified and include:

 Reagents, ligands and catalysts

 Heavy metals or other residual metals

 Inorganic salts

 Other materials (e.g., filter aids, charcoal)

Solvents are inorganic or organic liquids used as vehicles for the preparation of solutions or suspensions in the synthesis of a new drug substance.


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