Del. Code tit. 19, § 109

Any person whose interest is affected thereby may commence an action in the Superior Court of this State, in any of the 3 counties against the Department as defendant to determine the reasonableness and validity of any rule made pursuant to § 106 of this title, provided that no such action may be brought except as an appeal from the determination of the Department and within the time for such appeal, both as provided in § 106(e) of this title. Such action and pleadings thereon shall be governed by the laws and rules of practice applicable to other civil actions.