2937.21.00 - Cortisone, hydrocortisone, prednisone (dehydrocortisone), and prednisolone (dehydrohydrocortisone)

This HTS category encompasses specific corticosteroid hormones, their derivatives, and structural analogues that are either naturally occurring or synthesized. The key characteristic of these substances is their steroidal structure, and they are primarily used for their hormonal effects, particularly in treating inflammatory and autoimmune conditions. The scope includes cortisone, hydrocortisone, prednisone (also known as dehydrocortisone), and prednisolone (also known as dehydrohydrocortisone), all of which are potent anti-inflammatory agents.

This classification is distinguished from its siblings by the specific chemical identity of the steroidal hormones included. For instance, while 2937.22.00.00 covers halogenated derivatives of adrenal cortical hormones, this category focuses on the non-halogenated parent compounds and their closely related structural analogues. Similarly, it is distinct from the estrogen and progestin hormones (2937.23) and the "other" steroidal hormones and their derivatives (2937.29).

The subcategories within 2937.21.00.00 serve to break down the classification by the specific pharmaceutical name of the compound. This allows for more granular tracking and statistical reporting of these widely used medications, differentiating between cortisone, hydrocortisone, prednisone, and prednisolone based on their precise chemical structures and recognized medicinal applications.