According to definitions, a drug is a substance that is recognized in which pharmacopoeias?

The definition of a drug encompasses substances that are recognized in established pharmacopoeias, and this includes the United States Pharmacopeia (USP), the National Formulary (NF), and homeopathic pharmacopoeias. The USP is a prominent pharmacopoeia that provides a standard for medicines, including their identity, strength, quality, and purity. The NF complements the USP by focusing on the components of pharmaceuticals, such as excipients and various preparations. Additionally, the homeopathic pharmacopoeia recognizes substances used in homeopathic treatments.

By including all three pharmacopoeias in the definition, the correct answer reflects the broad and comprehensive nature of what constitutes a drug. This approach ensures that a variety of recognized standards and practices in medicine and pharmacy are accounted for, which is essential for ensuring the safety and efficacy of medications in diverse therapeutic contexts.