(648a) Troubleshooting and Performance Recovery of a Pharmaceutical Manufacturing Process Involving a Novel Asymmetric Hydrogenation and a Chiral Crystallization

A novel pharmaceutical manufacturing process to produce a chiral intermediate was successfully scaled-up to 2000 gallons in the factory during technology transfer. The manufacturing process involved several unit operations, and featured a unique high pressure enantioselective hydrogenation to produce the chiral intermediate at > 93% ee (enantiomeric excess), as well as a distillative chiral crystallization to purify the product to > 99% ee.

During the second manufacturing campaign, erosion in chiral purity, and elevated impurity levels were observed in the isolated intermediate. This erosion in purity was unexpected, and had potential implications on the quality of the product in the subsequent step. As a result, a thorough investigation was launched during the campaign to uncover the root causes of the process deviation, and to promptly recover batch performance.

The troubleshooting effort took into account the differences in operational parameters for each unit operation between campaign I and II, as well as process optimization changes that were in effect for campaign II. The confounding nature of the process parameters posed a challenge to the investigation and made a deviation analysis particularly difficult. Nevertheless, the investigation successfully identified two key factors contributing to the erosion in purity: the operating pressure during the distillative chiral crystallization and the overall train cycle time. Consequently, a process recovery strategy was implemented, and batch performance was restored for the remainder of the campaign with safeguards put in place to protect against future purity erosion. The troubleshooting approach, along with its findings, and highlights of the process recovery strategy will be presented.