Editorial pubs.acs.org/OPRD
Special Feature Section: Engineering Contributions to Process Chemistry he first special feature issue on Engineering Contributions to Chemical Process Development in Organic Process Research & Development was published in October 2013 (Vol. 17, issue 10) and included a wide range of papers on chemical kinetics, process modeling, crystallization, drying, and so forth. Following on that success, this issue brings the second special feature on Engineering Contributions, which continues to address challenges in chemical and pharmaceutical development with innovative ideas and technologies. With the everincreasing need to produce the highest quality of pharmaceutical products through in-depth process understanding, meet bioavailability and formulation challenges by tailoring the powder properties of the API, and design robust, cost-effective processes, innovation in process engineering is reaching new heights. This special feature brings a flavor of the cutting-edge research conducted by industry and academia including examples where close collaborations between the two have led to significant breakthroughs. The 10 articles in this issue consist of a mix of practical solutions to day-to-day engineering challenges, state-of-the-art tools and techniques for better process understanding and control, and exploratory new technologies to tackle perplexing problems. While batch processing can be the default mode of operation especially in the pharmaceutical industry, there is a growing shift toward continuous processing as it enables consistent manufacturing with better process control in addition to providing opportunities for improved yield, quality, and safety. Lakerveld and his associates have demonstrated how an integrated control strategy for an end-to-end process can be implemented at the pilot scale allowing for tight control of critical material attributes with a combination of feedforward and feedback control. Sharma et al. developed a continuous flow nitration significantly increasing the selectivity of the desired product, while Wang et al. have applied continuous centrifugal contactor separators for enantiomeric separation by biphasic chiral recognition. Several articles in this feature address such challenges in scale-up of chemical processes for various unit operations. The articles by Mohan et al. provide practical approaches to robust scale-up of solid suspension mixing and comilling. The applicability of a quick and easy method to assess solid suspension in plant reactors with an implementable decision flowchart is demonstrated at different scales, while the second paper identifies key comilling parameters and material attributes that impact comill performance through a systematic study. In the article by Atherton et al., a methodology is proposed to predict outcomes of hydrogenation reactions in plant reactors based on small-scale lab studies in a bubble reactor. This overcomes some of the difficulties associated with the scale-up of hydrogenations, which requires similarity of the hydrogen concentration in solution, with the concentration ideally being close to the saturated concentration. This is made more complicated as the gas−liquid mass transfer coefficient
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can vary significantly from lab to plant due to differences in the reactor/impeller geometry, mixing, and so forth. The powder properties of the API often impact significantly the formulation process, dissolution kinetics, and hence the bioavailability of the drug. Professor Myerson’s group at MIT has come up with innovative particle engineering technologies such as generation of uniform seed crystals via contact secondary nucleation in a continuous crystallization setup to achieve narrow particle size distribution and formation of API nanocrystals in controlled pore glass to significantly enhance dissolution kinetics. Morrison et al. have established a correlation of surface area and flowability to the particle size of an API through detailed characterization of different measures of particle sizes. Finally, the application of PAT to further process understanding is illustrated in the article by Drexler et al. where not only IR but also online NMR is used to study the kinetics of competitive reactions. In summary, these articles encompass a wide range of practically relevant topics such as continuous processes, PAT, crystallization, and scale-up to enable efficient process development. We hope OPR&D readers are inspired to apply these engineering approaches to their process development work.
David J. Lamberto Chemical Process Development and Commercialization, Merck Sharp & Dohme Corp., 126 East Lincoln Avenue, Rahway, New Jersey 07065, United States
Mark T. Maloney Chemical Research and Development, Pfizer Inc., Eastern Point Road, Groton, Connecticut 06340, United States
Saravanababu Murugesan Medication and Procedural Solutions, BD Medical, Becton Dickinson Co., 1 Becton Drive, Franklin Lakes, New Jersey 07417, United States
Srividya Ramakrishnan*
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Integrated Product Development, Dr. Reddy’s Laboratories Ltd., Bachupally, Hyderabad 500090, India
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[email protected]. Notes
Views expressed in this editorial are those of the author and not necessarily the views of the ACS.
Special Issue: Engineering Contributions to Process Chemistry Published: September 18, 2015 1075
DOI: 10.1021/acs.oprd.5b00254 Org. Process Res. Dev. 2015, 19, 1075−1075
