21 C.F.R. § 1316.62
Rulings of the presiding officer may not be appealed to the Administrator prior to his consideration of the entire hearing without first requesting the consent of the presiding officer. Within ten (10) business days of receipt of a party's request for such consent, the presiding officer shall certify on the record or in writing his determination of whether the allowance of an interlocutory appeal is clearly necessary to prevent exceptional delay, expense or prejudice to any party, or substantial detriment to the public interest. If the presiding officer denies an interlocutory appeal, he shall, within three (3) business days, transmit his determination and the parties' filings related to the interlocutory appeal to the Administrator for the Administrator's discretionary review. If an interlocutory appeal is allowed by the presiding officer or if the Administrator determines that an appeal is warranted under this section, any party to the hearing may file a brief in quintuplicate with the Administrator within such period that the Administrator directs. No oral argument will be heard unless the Administrator directs otherwise.
21 C.F.R. §1316.62