(a) A drug or device is adulterated if

(1) it consists in whole or in part of a filthy, putrid, or decomposed substance;

(2) it has been produced, prepared, packed, or held under insanitary conditions in which it may have been contaminated with filth, or in which it may have been rendered injurious to health;

(3) it is a drug and its container is composed, in whole or in part, of poisonous or deleterious substance which may render the contents injurious to health; or

(4) it is a drug and it bears or contains, for purposes of coloring only, a coal tar other than one from a batch certified under the authority of the federal act.

(b) A drug is adulterated if it purports to be or is represented as a drug the name of which is recognized in an official compendium, and its strength differs from, or its quality or purity falls below, the standard set forth in the compendium. The determination as to strength, quality, or purity shall be made in accordance with the tests or methods of assay set forth in the compendium, or in the absence or inadequacy of tests or methods of assay, those prescribed under authority of the federal act. A drug defined in an official compendium is not adulterated under this subsection because it differs from the standard of strength, quality, or purity set forth in the compendium, if its difference in strength, quality, or purity is plainly stated on its label. When a drug is recognized in both the United States Pharmacopoeia and the Homeopathic Pharmacopoeia of the United States it is subject to the requirements of the United States Pharmacopoeia unless it is labeled and offered for sale as a homeopathic drug, in which case it is subject to the provisions of the Homeopathic Pharmacopoeia of the United States and not to those of the United States Pharmacopoeia.

(c) A drug is adulterated if it is not subject to the provisions of (b) of this section and its strength differs from, or its purity or quality falls below, that which it purports or is represented to possess.

(d) A drug is adulterated if a substance has been

(1) mixed or packed with it to reduce its quality or strength; or

(2) substituted wholly or in part for it.