To verify active pharmaceutical ingredient manufacturers' GMP (Good Manufacturing Practice) certification, you can follow these steps based on the regulatory region or the issuing authority:

1. Verify Chinese GMP Certificates
You can verify Chinese GMP certificates through the official website of the National Medical Products Administration (NMPA) of China. Here’s how:
- Visit the [NMPA website] and use the search interface to enter the API name or active pharmaceutical ingredient manufacturers’s name.
- Compare the details on the website with the certificate provided by the active pharmaceutical ingredient manufacturers. Note that invalid or canceled GMP certificates will not be shown.

2. Verify EU GMP Certificates
For EU GMP certificates, you can use the EudraGMDP database:
- Access the [EudraGMDP database] to search for the active pharmaceutical ingredient manufacturers’s GMP certificate.
- Ensure that the certificate details match those provided by the active pharmaceutical ingredient manufacturers.

3. Verify US FDA Certificates
To verify GMP certificates issued by the US FDA:
- Visit the [FDA website] and use their search tools to find the active pharmaceutical ingredient manufacturers’s facility inspection records.
- Check for the latest inspection reports and compliance status.

4. Verify Australian TGA Certificates
For Australian GMP certificates issued by the Therapeutic Goods Administration (TGA):
- Use the [ARTG Search]to verify the active pharmaceutical ingredient manufacturers’s certificate.
- Enter the product name or active pharmaceutical ingredient manufacturers’s name to check if the certificate is valid.

5. Verify ISO Certifications
ISO certifications can be verified through the official certification body websites or databases:
- Use the [ISO certification verification interface]to search for the active pharmaceutical ingredient manufacturers’s ISO certificate.
- Enter the active pharmaceutical ingredient manufacturers’s name or certificate number to verify its validity.

Additional Tips
- Check for Official Certificates: Always request the official GMP certificate from the active pharmaceutical ingredient manufacturers and verify its authenticity through the relevant regulatory authority.
- Contact the Regulatory Authority: If you have doubts, you can directly contact the regulatory authority (e.g., FDA, EMA, NMPA) for verification.
- Third-Party Audits: Consider conducting third-party audits or engaging a reputable certification body to verify the active pharmaceutical ingredient manufacturers’s compliance.

By following these steps, you can ensure that the GMP certification provided by the active pharmaceutical ingredient manufacturers is valid and reliable.