An introduction to the Prequalification of Active Pharmaceutical Ingredients
The WHO Prequalification of Medicines Programme (PQP) facilitates access to quality medicines through assessment of products and inspection of manufacturing sites. Since good-quality active pharmaceutical ingredients (APIs) are vital to the production of good-quality medicines, PQP has started a pilot project to prequalify APIs.
WHO-prequalified APIs are listed on the WHO List of Prequalified Active Pharmaceutical Ingredients. The list provides United Nations agencies, national medicines regulatory authorities (NMRAs) and others with information on APIs that have been found to meet WHO-recommended quality standards. It is believed that identification of sources of good-quality APIs will facilitate the manufacture of good-quality finished pharmaceutical products (FPP) that are needed for procurement by UN agencies and disease treatment programmes.
Details of the API prequalification procedure are available in the WHO Technical Report Series TRS953, Annex 4. Key elements of this document are given below.
What is API prequalification?
API prequalification provides an assurance that the API concerned is of good quality and manufactured in accordance with WHO Good Manufacturing Practices (GMP).
API prequalification consists of a comprehensive evaluation procedure that has two components: assessment of the API master file (APIMF) to verify compliance with WHO norms and standards and assessment of the sites of API manufacture to verify compliance with WHO GMP requirements.
Prequalification of an API is made with specific reference to the manufacturing details and quality controls described in the APIMF submitted for assessment. Therefore, for each prequalified API, the relevant APIMF version number will be included in the WHO List of Prequalified Active Pharmaceutical Ingredients.
Steps in the process
The WHO prequalification procedure for medicines and active pharmaceutical ingredients
Initially, an application is screened to determine whether it is covered by the relevant expression of interest (EOI). It is also screened for completeness; in particular, the formatting of the submitted APIMFs is reviewed. Once the application has been accepted, a WHO reference number is assigned to it.
A team of assessors then reviews the submitted APIMF, primarily at bimonthly meetings in Copenhagen. Invariably, assessors raise questions during assessment of the APIMF that require revision of the information submitted and/or provision of additional information, and/or replacementof certain sections within the APIMF. Applicants are contacted to resolve any issues raised by the assessors.
It is important that any prequalified API can be unambiguously identified with a specific APIMF. Therefore, once any and all issues regarding its production have been resolved, the applicant will be asked to submit an updated APIMF that incorporates any changes made during assessment. The version number of the revised and up-to-date APIMF will be included on the WHO List of Prequalified Active Pharmaceutical Ingredients, to serve as a reference regarding the production and quality control of that API.
For APIMFs that have already been accepted in conjunction with the prequalification of an FPP, full assessment is generally not required. Such APIMFs are reviewed only for key information and conformity with administrative requirements. Nonetheless, a request for further information may be made, to ensure that the APIMF meets all current norms and standards; PQP reserves the right to do so.
An assessment is also undertaken of WHO GMP compliance at the intended site(s) of API manufacture. Depending on the evidence of GMP supplied by the applicant, this may necessitate on-site inspection by WHO. If a WHO inspection is conducted and the site is found to be WHO GMP-compliant, the API will be recommended for prequalification. Additionally, a WHO Public Inspection Report (WHOPIR) will be published on the PQP web site.
When the APIMF and the standard of GMP at the intended manufacturing site(s) have each been found to be satisfactory, the API is prequalified and listed on the WHO List of Prequalified Active Pharmaceutical Ingredients.
The successful applicant will also be issued a WHO Confirmation of Active Pharmaceutical Ingredient Prequalification document. This document contains the accepted active ingredient specifications and copies of the assay and related substances test methodology. This document may be provided by the API manufacturers to interested parties at their discretion.
Maintenance of API prequalification status
Applicants are required to communicate to WHO any changes that have been made to the production and control of a WHO-prequalified API. This can either be in the form of an amendment, or as a newly-issued version of the APIMF. It is the applicant’s responsibility to provide WHO with the appropriate documentation (referring to relevant parts of the dossier), to prove that any intended or implemented change will not have or has not had a negative impact on the quality of the prequalified API. This may necessitate the updating of the information published on the WHO List of Prequalified Active Pharmaceutical Ingredients.
The decision to prequalify an API is based upon information available to WHO at that time, i.e. information in the submitted APIMF, and on the status of GMP at the facilities used in the manufacture and control of the API. The decision to prequalify an API is subject to change, should new information become available to WHO. For example, if serious safety and/or quality concerns arise in relation to a prequalified API, WHO may suspend the API until the investigative results have been evaluated by WHO and the issues resolved, or delist the API in the case of issues that are not resolved to WHO’s satisfaction.
Who can participate?
Any manufacturer of any active pharmaceutical ingredient (API) that is included on an Invitation to Submit an Expression of Interest for Product Evaluation can submit an application for product evaluation.
If an applicant is acting on behalf of a manufacturer, the actual manufacturer(s) of the API and any contract manufacturers, must be clearly listed in the cover letter
To manufacturers of medicinal products
The vision of the WHO Prequalification of Medicines Programme (PQP) is of a world in which good-quality medicines are available to all those who need them. PQP facilitates access to good-quality medicines through assessment of products and inspection of manufacturing facilities. Since good-quality active pharmaceutical ingredients (APIs) are vital to the production of good-quality medicines, PQP has started a project to prequalify APIs.
APIs that meet assessment criteria will be added to the WHO List of Prequalified Active Pharmaceutical Ingredients. Manufacturers and National Regulatory Authorities (NRAs) can use the List to help them identify APIs of assured quality, while UN agencies and others can use the List to supplement the information found on the WHO List of Prequalified Medicines Products.
The issuing of an invitation to submit an expression of interest (EOI) is the first step in the prequalification process. Each invitation is developed in consultation with WHO disease programmes, other UN agencies (including UNAIDS and UNICEF) and UNITAID. The 1st Invitation to manufacturers of APIs to submit a request for an evaluation of an API was issued in October 2010.
The current EOI is:
In applying for evaluation of an API, manufacturers are requested to submit a covering letter, application form, API master file (APIMF), site master file (SMF), and evidence of current GMP certification to PQP. Thereafter, PQP will undertake a comprehensive evaluation of the APIMF and review the GMP status of the manufacturing site(s). In some cases, PQP will request additional information and may also inspect the manufacturing site(s).
Prequalification of Active Pharmaceutical Ingredients (APIs) – Procedural Guidance
Any applicant who is unclear over any aspect of the API prequalification procedure should contact PQT prior to submission, since incorrect submissions will be rejected.