Pharmaceutical Salts: Comprehensive Insights From Fundamental Chemistry to FDA Approvals (2019-2023)

Pharmaceutical salts are a cornerstone in drug development, offering a robust, economical, and industry-friendly option for improving the crucial physicochemical properties of drugs, particularly solubility and dissolution. This review article explores all critical aspects of salt formation, including its importance, the basic chemistry involved, the principles governing counterion selection, the range of counterions used, and the methods for preparing salts along with their advantages and limitations. Additionally, it explores analytical techniques for confirming salt formation and the different approaches various countries adopt in considering new salts as intellectual property. Furthermore, the review sheds light on US FDA-approved salts from 2019 to 2023, providing a unique perspective by analyzing trends in counterion selection observed in FDA-approved salts during this period. Despite the extensive literature on pharmaceutical salts, a comprehensive review addressing all these critical aspects in a single article with a focus on current trends and particularly on US FDA-approved salts from 2019 to 2023 is lacking. This review bridges this gap by thoroughly exploring all mentioned facets of pharmaceutical salts and providing an up-to-date overview.