## 1 Introduction  
Continuous processing reactors are essential for optimizing pharmaceutical synthesis by offering continuous flow, real-time monitoring, and a modular design. They enable control over reaction parameters and reduce waste generation. Their automation capabilities and scalability further enhance their efficiency and flexibility in pharmaceutical manufacturing [1]. Additionally, the integration of AM technology improves the potential of continuous processing by facilitating the fabrication of customized reactors with complex designs [2]. These AM-based reactors facilitate enhanced regulation over the reaction parameters, resulting in optimized operational processes, lower manufacturing expenditures, and elevated product standards [3]. Pharmaceutical companies are under growing demands to streamline their operations, minimize expenses, and elevate the caliber of their products. In the pharmaceutical industry, AM technology offers transformative solutions for drug development and personalized medicine. It allows for the fabrication of precise dosage forms with tailored drug release profiles, improving patient adherence and efficacy [4]. AM enables the production of complex drug delivery systems, such as implants and transdermal patches, as well as patient-specific medications, enhancing treatment outcomes. Moreover, it enables the swift creation of prototype pharmaceutical formulations, expediting the drug development lifecycle and diminishing the associated expenditures. Furthermore, it offers innovative approaches for personalized healthcare and drug delivery. The integration of continuous processing reactors and AM technology opens up a promising avenue for the synthesis of pharmaceutical intermediates, particularly Schiff base compounds and metronidazole derivatives. These compounds have garnered significant attention due to their diverse biological activities and potential therapeutic applications. By leveraging the advantages of continuous flow and the design flexibility offered by AM, researchers can optimize reaction conditions, increase product yield, and improve the overall efficiency of pharmaceutical synthesis. This synergistic approach not only addresses the challenges faced by the pharmaceutical industry but also paves the way for the development of novel drug candidates with improved efficacy and reduced side effects. Various reaction types are used to synthesize pharmaceutical intermediates, including the formation of Schiff base compounds through condensation reactions. Schiff bases constitute a significant category of organic compounds that possess a diverse array of applications [5]. They have been extensively used as ligands for forming transition metal complexes [6]. Furthermore, Schiff bases have demonstrated a wide range of biological effects, including antibacterial, antifungal, and anti-inflammatory capabilities [7]. Schiff bases incorporating heterocyclic components have attracted substantial interest owing to their multifaceted biological activities, encompassing anticancer, antiviral, fungicidal, bactericidal, and anti-HIV properties [8]. Developing new chemotherapeutic Schiff bases has become an area of focus for medicinal chemists [9]. Numerous research teams have dedicated their efforts to the synthesis and biological evaluation of Schiff base compounds [10]. As an example, scientists have made different Schiff base compounds from 2-aminothiazoles and substituted benzaldehyde and then tested how well they fight three types of human tumor cells in the lab [11]. Other research groups have also made Schiff bases from 7-amino-4-methylcoumarin and benzaldehyde, studying their pain-relieving and anti-inflammatory effects. Their findings revealed that certain prepared Schiff base compounds have comparable or even superior potency compared to reference drugs used for these therapeutic applications [12].