Key Fabrications of Chitosan Nanoparticles for Effective Drug Delivery Using Flow Chemistry Reactors

Introduction

Chitosan nanoparticles have garnered considerable interest in the field of drug delivery owing to their distinctive properties, including biocompatibility, biodegradability, low toxicity, and ability to encapsulate a wide range of drugs. However, the conventional methods (eg, the drop method) for synthesizing chitosan nanoparticles often face limitations in regard to controlling the particle size, morphology, and scalability, hindering their extensive application in drug delivery systems. To overcome these challenges, this study explores using a novel flow chemistry reactor design for fabricating clindamycin-loaded chitosan nanoparticles.

Methods

By varying two critical operating parameters of flow chemistry, namely, the flow rate ratio and total flow rate, the impact of these parameters on the properties of chitosan nanoparticles is investigated using a central composite experimental design.

Results

The optimized conditions for nanoparticle preparation yielded remarkable results, with chitosan nanoparticles exhibiting a small size of 371.60 nm and an extremely low polydispersity index of 0.042. Furthermore, using novel design flow chemistry reactor, the productivity of chitosan nanoparticles was estimated to be 25,402.17 mg/min, which was ~12.71 times higher than that obtained via batch synthesis.

Conclusion

The findings of this study indicate that the use of novel design flow chemistry reactor is promising for synthesizing clindamycin-loaded chitosan nanoparticles and other polymeric nanoparticles intended for drug delivery applications. This is primarily attributed to their ability to produce nanoparticles with a considerably reduced particle size distribution and smaller overall size. The demonstrated high productivity of this technique suggests the potential for industrial-scale nanoparticle manufacturing.

Three-Dimensional-Printed Vortex Tube Reactor for Continuous Flow Synthesis of Polyglycolic Acid Nanoparticles with High Productivity

Polyglycolic acid (PGA) nanoparticles show promise in biomedical applications due to their exceptional biocompatibility and biodegradability. These nanoparticles can be readily modified, facilitating targeted drug delivery and promoting specific interactions with diseased tissues or cells, including imaging agents and theranostic approaches. Their potential to advance precision medicine and personalized treatments is evident. However, conventional methods such as emulsification solvent evaporation via batch synthesis or tubular reactors via flow chemistry have limitations in terms of nanoparticle properties, productivity, and scalability. To overcome these limitations, this study focuses on the design and development of a 3D-printed vortex tube reactor for the continuous synthesis of PGA nanoparticles using flow chemistry. Computer-aided design (CAD) and the design of experiments (DoE) optimize the reactor design, and computational fluid dynamics simulations (CFD) evaluate the mixing index (MI) and Reynolds (Re) expression. The optimized reactor design was fabricated using fused deposition modeling (FDM) with polypropylene (PP) as the polymer. Dispersion experiments validate the optimization process and investigate the impact of input flow parameters. PGA nanoparticles were synthesized and characterized for size and polydispersity index (PDI). The results demonstrate the feasibility of using a 3D-printed vortex tube reactor for the continuous synthesis of PGA nanoparticles through flow chemistry and highlight the importance of reactor design in nanoparticle production. The CFD results of the optimized reactor design showed homogeneous mixing across a wide range of flow rates with increasing Reynolds expression. The residence time distribution (RTD) results confirmed that increasing the flow rate in the 3D-printed vortex tube reactor system reduced the dispersion variance in the tracer. Both experiments demonstrated improved mixing efficiency and productivity compared to traditional tubular reactors. The study also revealed that the total flow rate had a significant impact on the size and polydispersity index of the formulated PGA nanoparticle, with the optimal total flow rate at 104.46 mL/min, leading to smaller nanoparticles and a lower polydispersity index. Additionally, increasing the aqueous-to-organic volumetric ratio had a significant effect on the reduced particle size of the PGA nanoparticles. Overall, this study provides insights into the use of 3D-printed vortex tube reactors for the continuous synthesis of PGA nanoparticles and underscores the importance of reactor design and flow parameters in PGA nanoparticle formulation.

Development of an Add-On Device Using 3D Printing for the Enhancement of Drug Administration Efficiency of Dry Powder Inhalers (Accuhaler)

The goal of this study was to develop an add-on device for dry powder inhalers (Accuhaler) via 3D printing to improve drug administration efficiency in patients with limited inspiratory capacity, including young children, the elderly, and those with chronic obstructive pulmonary disease. With salmeterol xinafoate and fluticasone propionate as model active pharmaceutical ingredients (API), the emitted API doses were used to assess the effectiveness of the add-on device. The APIs were quantified by an HPLC assay validated for specificity, range, linearity, accuracy, and precision. The motor power of the add-on device could be regulated to moderate fan speed and the air flow in the assembled device. When 50–100% of the fan motor power of the add-on device was used, the emitted dose from the attached dry powder inhaler (DPI) was increased. A computational fluid dynamics application was used to simulate the air and particle flow in the DPI with the add-on device in order to elucidate the operating mechanism. The use of the add-on device combined with a sufficient inhalation flow rate resulted in a larger pressure drop and airflow velocity at the blister pocket. As these characteristics are associated with powder fluidization, entrainment, and particle re-suspension, this innovative add-on device might be utilized to enhance the DPI emitted drug dose for patients with low inspiratory rates and to facilitate the provision of adequate drug doses to achieve the treatment outcomes.