(1) If, when a drug is sold under or by a name recognized in the United States Pharmacopoeia or National Formulary, it differs from the standard of strength, quality or purity as determined by the test laid down in the United States Pharmacopoeia or National Formulary official at the time of investigation. No drug defined in the United States Pharmacopoeia or National Formulary shall be deemed to be adulterated under this subdivision if the standard of strength, quality or purity is plainly stated upon the bottle, box or other container thereof although the standard may differ from that determined by the test laid down in the United States Pharmacopoeia or National Formulary.

(2) If its strength or purity falls above or below the professed quality under which it is sold.

(3) If it violates the definition of adulteration as stated in the Federal Food, Drug and Cosmetic Act [21 U.S.C. § 301 et seq.].