In recent years many efforts have been devoted to the screening and the study of new solid-state forms of old active pharmaceutical ingredients (APIs) with salification or co-crystallization processes, thus modulating final properties without changing the pharmacological nature. Salts, hydrates/solvates, and cocrystals are the common solid-state forms employed. They offer the intriguing possibility of exploring different pharmaceutical properties for a single API in the quest of enhancing the final drug product. New synthetic strategies and advanced characterization techniques have been recently proposed in this hot topic for pharmaceutical companies. This paper reviews the recent progresses in the field particularly focusing on the characterization challenges encountered when the nature of the solid-state form must be determined. The aim of this article is to offer the state-of-the-art on this subject in order to develop new insights and to promote cooperative efforts in the fascinating field of API salt and cocrystal forms.

近年来，人们已经进行了许多努力来筛选和研究具有成盐作用或共结晶过程的旧活性药物成分（API）的新固态形式，从而在不改变药理性质的情况下调节最终特性。盐，水合物/溶剂化物和共晶体是常用的固态形式。它们提供了探索单一药物原料药的不同药物特性以提高最终药物质量的有趣可能性。最近，在这个热门话题中，针对制药公司提出了新的合成策略和先进的表征技术。本文回顾了该领域的最新进展，尤其关注必须确定固态形式的性质时遇到的表征挑战。