An active pharmaceutical ingredient (API) was isolated from solution as a crystalline hydrate and then converted to the desired weakly crystalline form during drying. Incomplete solvent removal was observed at the factory scale. It was suspected that differences in the processing equipment and drying conditions led to the rapid loss of water from the solids, early form conversion, and subsequent trapping of the process solvent above specification levels. Experiments were conducted to gain a better understanding of the drying process and test theories for solvent trapping. The practical methods and techniques described here are considered broadly applicable to API drying process development; findings associated with solvent entrapment may be common across compounds undergoing a form transition during drying. This article presents experimental results that led to an increased process understanding and identification of conditions for successful drying of the API.

中文翻译：

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API干燥过程中的形式转化和溶剂截留

从溶液中分离出活性药物成分（API），为结晶水合物，然后在干燥过程中转化为所需的弱结晶形式。在工厂规模上观察到溶剂去除不完全。怀疑加工设备和干燥条件的差异会导致固体中水分迅速流失，早期形式转化以及随后将加工溶剂截留到规格水平以上。进行实验以更好地了解干燥过程和溶剂捕集的测试理论。这里描述的实用方法和技术被认为广泛适用于API干燥工艺的开发。在干燥过程中经历形态转变的化合物中，与溶剂截留有关的发现可能很常见。