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U.S. Department of Health and Human Services

About FDA

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Recommendations for Improving Submissions of a "Controlled Correspondence" to the Office of Generic Drugs

The Office of Generic Drugs (OGD) is willing to provide assistance to pharmaceutical companies and the related industry regarding a variety of questions posed as “Controlled Correspondences.”  It is important that the system for review of these correspondences is as efficient and effective as possible.  Please note that the OGD already makes available dissolution information and several hundred individual product bioequivalence study recommendations on the internet. 

The OGD has the following recommendations to assist having appropriate questions answered: 

  • Sometimes it is obvious the requestor has researched an issue prior to submitting a controlled correspondence. Please perform adequate research within your firm and with all potential resources before considering submission of a controlled correspondence.  Please provide information about what research has been done with all pertinent information and make sure questions are as specific as possible.  Further, with respect to excipients, we recommend that firms maintain an internal database of their own approved products and any feedback that may have been received from the agency.  By maintaining an internal database, a firm may be able to justify an excipients maximum daily dose without submitting a controlled correspondence.
  • Please submit only one copy of the correspondence to the appropriate contact. Do not submit multiple copies of the same question(s) (ex, fax and FedEx; email and FedEx) at different times to the same or different persons.  If the correspondence is a follow-up after an initial response to a control, please provide the previous control number prominently so the correspondence may be tracked accordingly.
  • Verify the correspondence is not a review issue that should be submitted to an existing ANDA.  Many questions related to an ANDA are review issues and should be submitted to the ANDA so it may be included as part of the full administrative record.  If the request is a controlled correspondence document, clearly mark the submission as such to assure it is not inadvertently placed in an ANDA.
  • In general, we are only able to provide a response to the United States agent or representative of foreign firms, similar to what is necessary when submitting an ANDA.  Some responses are by telephone while others may be answered via an official letter. The Office does not make a practice of contacting non-U.S. Agent representatives.  In addition, any email submission of a controlled correspondence request must be sent through a firm’s corporate email system to assure appropriate security.  We are not able to respond to emails which are received from general accounts such as gmail®, AOL®, Yahoo®, etc. A phone number and fax number should be included for the correspondence contact.
  • Due to our workload, the Office does not routinely send out emails confirming receipt of the incoming correspondence.  If the requestor has not received a response from OGD within 45 days, please contact the OGD.
  • For an assessment of a formulation or Qualitative (Q1) and Quantitative (Q2) formulation review, the following information from the "Approved Drug Products with Therapeutic Equivalence Evaluations”  (the Orange Book) for the product is requested: 

Active Ingredient

Dosage Form; Route

Proprietary Name



Application Number

Product Number

Approval Date

Reference Listed Drug


  • Controlled Correspondences for formulation assessment of multiple drug products should be submitted as a separate request for each product. A maximum of three proposed formulations for a drug product may be submitted per correspondence. Formulation request for a drug product with multiple strengths should be submitted as a separate correspondence.
  • There should be a maximum of three inactive ingredients per request for assessment of individual inactive ingredients.
  • The Office does not pre-review proposed drug product formulations unless the product is required to be Q1 and Q2 with the Reference Listed Drug Product.
  • A controlled correspondence should not include pharmacology/toxicology data.  If the information is necessary to justify an inactive ingredient, it should be submitted as part of the original ANDA submission for review.
  • If a correspondence for a product requires review by more than one discipline (i.e. Chemistry, Bioequivalence, and Labeling), please submit separate requests for the product for each review discipline.   

The Office of Generic Drugs will assist the industry by providing information through controlled correspondence responses.  But to be effective and efficient, the system should not be abused or over utilized.

Controlled Correspondences should be emailed, faxed or a hard copy mailed to: 

Email: GenericDrugs@FDA.HHS.Gov

Fax Number: 240-276-9327 

Mailing address: Control Correspondence Coordinator

                            Office of Generic Drugs (HFD 600)

                            Metro Park North VII

                            7620 Standish Place

                            Rockville, MD 20855

Please submit one control per subject matter. Please do not send duplications of the same correspondence by multiple means. This will only delay the processing of your correspondence.