The synthesis of complex organic molecules requires several stages, from ideation to execution, that require time and effort investment from expert chemists. Here, we report a step toward a paradigm of chemical synthesis that relieves chemists from routine tasks, combining artificial intelligence–driven synthesis planning and a robotically controlled experimental platform. Synthetic routes are proposed through generalization of millions of published chemical reactions and validated in silico to maximize their likelihood of success. Additional implementation details are determined by expert chemists and recorded in reusable recipe files, which are executed by a modular continuous-flow platform that is automatically reconfigured by a robotic arm to set up the required unit operations and carry out the reaction. This strategy for computer-augmented chemical synthesis is demonstrated for 15 drug or drug-like substances.
Computer-aided synthesis planning (CASP) tools can propose retrosynthetic pathways and forward reaction conditions for the synthesis of organic compounds, but the limited availability of context-specific data currently necessitates experimental development to fully specify process details. We plan and optimize a CASP-proposed and human-refined multistep synthesis route toward an exemplary small molecule, sonidegib, on a modular, robotic flow synthesis platform with integrated process analytical technology (PAT) for data-rich experimentation. Human insights address catalyst deactivation and improve yield by strategic choices of order of addition. Multi-objective Bayesian optimization identifies optimal values for categorical and continuous process variables in the multistep route involving 3 reactions (including heterogeneous hydrogenation) and 1 separation. The platform's modularity, robotic reconfigurability, and flexibility for convergent synthesis are shown to be essential for allowing variation of downstream residence time in multistep flow processes and controlling the order of addition to minimize undesired reactivity. Overall, the work demonstrates how automation, machine learning, and robotics enhance manual experimentation through assistance with idea generation, experimental design, execution, and optimization.
Traditional pharmaceutical manufacturing is based on a complex supply chain that is vulnerable to spikes in demand and interruptions. Continuous pharmaceutical production in compact modules is a potential solution that allows for drug manufacturing when and where it is needed with significantly shorter lead times. As part of the Pharmacy on Demand (PoD) initiative, we demonstrate the potential for end-to-end manufacturing of multiple drug substances in reconfigurable devices, under common industrial constraints, and within a challenging manufacturing time frame. A new set of refrigerator-sized modules was constructed for the synthesis, isolation, and formulation of several drugs, with focus on achieving high manufacturing throughputs, and allowing for the production of pharmaceutical tablets. Their operation is demonstrated with the synthesis and formulation of USP-compliant tablets of diazepam, diphenhydramine hydrochloride, and ciprofloxacin hydrochloride, as well as liquid formulations of lidocaine hydrochloride and atropine sulfate.
Continuous manufacturing of pharmaceuticals and fine chemicals is attractive due to its small physical footprint, consistent product quality, and demonstrated benefits from safety, economic, and environmental perspectives. However, handling solids...
The
experimental approach taken and challenges overcome in developing
a high-purity production (>100 g) scale process for the telescoped
synthesis of the antibiotic ciprofloxacin is outlined. The process
was first optimized for each step sequentially with regard to purity
and yield, with necessary process changes identified and implemented
before scaling for longer runs. These changes included implementing
a continuous liquid–liquid extraction (CLLE) step and eliminating
and replacing the base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) initially
used in the ring-closure step due to DBU plausibly forming a decomposition
side product that negatively impacted the final product purity. Process
conditions were scaled 1.5–2-fold in order to enable the ultimate
project goal of producing enough crude ciprofloxacin within 24 h to
manufacture 1000 250 mg tablets. Working toward this goal, several
production-scale runs were carried out to assess the reproducibility
and robustness of the finalized process conditions, with the first
three steps being run continuously up to 22 h and the last two steps
being run continuously up to 10 h. The end result is a process with
a throughput of ∼29 g/h (∼700 g/24 h) with a crude product
stream profile of 94 ± 2% and 34 ± 3 mg/mL after five chemical
transformations across four reactors and one continuous CLLE unit
operation with each intermediate step maintaining a purity >95%
by
HPLC.
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