20.93—Changes to formulas.
(a) General.
Except as provided in paragraph (b) of this section, any change of ingredients or quantities of ingredients listed in an appoved formula shall constitute a different article for which a different approved formula is required by § 20.91.
(1)
A change from an ingredient identified in the formula by a brand name to the same quantity of a chemically identical ingredient acquired under a different brand name, or