Developments of small molecules as inhibitors for carbonic anhydrase isoforms

Carbonic anhydrases are ubiquitous, and their role in the hydration of carbon dioxide is essential for the survival of many tissues and organs. However, their association with many pathological diseases, especially in glaucoma, Alzheimer's, obesity, epilepsy, and tumorigenesis, has prompted the design and synthesis of novel carbonic anhydrase inhibitors (CAIs). Herein we describe (1) approaches used in the design of CAIs and (2) synthesis of small molecules as CAIs within the last five years. Despite the active research in this area, there are still more avenues to explore, especially selective inhibition of CA I, CA IX, and XII. These isoforms would continue to open up a diversity of carbonic anhydrase inhibitors containing 1,2,3-triazoles, imidazolone, pyrrolidone, thiadiazole, isatin, and glycoconjugates as part of their molecular frameworks.