FDA has published all the necessary NDA patent information in the Orange Book. The ANDA applicant for the generic drug approval has to submit the reference-listed drugs (RLD) information i.e., the NDA related patents for the approval. FDA recommends that when providing patent information, applicants include the expiration date for each patent, whether the RLD is protected by any pediatric exclusivity, and when any such pediatric exclusivity will expire.
The FDA cannot approve the ANDA application until the NDA listed patents are expired. In order to get approved for a generic, the ANDA applicant has to make certifications or statement for each patent issued by the U.S. Patent and Trademark Office and subsequently listed in the Orange Book that claims (1) the drug substance, (2) the drug product, and/or (3) a use of the RLD that is cited by the ANDA. There are four type of certifications for a generic drug (ANDA) approval for US market. The four certifications are commonly referred as paragraph I, II, III and IV.
Paragraph I Certification: If the Orange Book does not list a patent for the RLD, the ANDA applicant must certify that such patent information has not been submitted by the NDA holder for listing in the Orange Book.
For each patent issued by the U.S. Patent and Trademark Office and subsequently listed in the Orange Book, the applicant must certify to one of the following paragraphs:
Paragraph II Certification: That the patent information has expired.
Paragraph III Certification: The date on which the patent will expire.
Paragraph IV Certification: That the patent is invalid, unenforceable, or will not be infringed by the manufacture, use, or sale of the drug product for which the ANDA is submitted.
Applicants submitting a Paragraph IV Certification must provide the following language:
I, (name of applicant), certify that Patent No. …….. is invalid, unenforceable, or will not be infringed by the manufacture, use, or sale of (name of proposed drug product) for which this application is submitted.
Applicants submitting a Paragraph IV Certification must also certify that they will provide notice to the owner of the patent(s) and to the holder of the approved application that lists the patent(s) that is/are being challenged.
 Approvals at USFDA){kind=link}