All certificates of authorization previously issued under either Article 3 of this chapter, the "Postsecondary Educational Authorization Act of 1978," or Article 4 of Chapter 4 of this title, the "Georgia Proprietary School Act," as such articles and provisions existed immediately prior to July 1, 1991, shall remain valid until their expiration date or until such certificate can be renewed in accordance with the terms of this part and the rules, regulations, and standards of the commission. The commission is authorized to adopt interim rules and regulations to allow for the transition to this part for institutions regulated under the aforementioned articles.