Preparation of Drug-Loaded Liposomes with Multi-Inlet Vortex Mixers

Manufacturing of Liposomes Using a Stainless-Steel Microfluidic Device: An Investigation into Design of Experiments

Liposomes are highly beneficial nanocarrier systems due to their biocompatibility, low toxicity, and exceptional inclusiveness, which lead to improved drug bioavailability. For biological applications, accurate control over these nanoparticles' mean size and size distribution is essential. Micromixers facilitate the continuous production of liposomes, enhancing the precision of size regulation and reproducibility. In this research, the performance of a stainless steel 316L micromixer was evaluated by using COMSOL Multiphysics simulations. The liposomes were precisely optimized using design of experiments techniques in a microfluidic setup, and then dexamethasone sodium phosphate (DSP) was successfully encapsulated in liposome nanoparticles. The physicochemical characteristics of liposomes, such as their ζ-potential, size, DSP loading capacity, encapsulation efficiency, and drug release, were assessed. Transmission electron microscopy and dynamic light scattering analysis were used to examine the structures of the liposomes. The drug release kinetics study was conducted to analyze the drug delivery system, and the Higuchi equation was determined to be the most suitable equation. The microfluidic chip was shown to be capable of creating small-sized liposomes with a size as small as 130 nm, exhibiting monodispersed characteristics and low polydispersity liposome populations.

Advances in Microfluidic-Based Core@Shell Nanoparticles Fabrication for Cancer Applications

Current research in cancer therapy focuses on personalized therapies, through nanotechnology-based targeted drug delivery systems. Particularly, controlled drug release with nanoparticles (NPs) can be designed to safely transport various active agents, optimizing delivery to specific organs and tumors, minimizing side effects. The use of microfluidics (MFs) in this field has stood out against conventional methods by allowing precise control over parameters like size, structure, composition, and mechanical/biological properties of nanoscale carriers. This review compiles applications of microfluidics in the production of core-shell NPs (CSNPs) for cancer therapy, discussing the versatility inherent in various microchannel and/or micromixer setups and showcasing how these setups can be utilized individually or in combination, as well as how this technology allows the development of new advances in more efficient and controlled fabrication of core-shell nanoformulations. Recent biological studies have achieved an effective, safe, and controlled delivery of otherwise unreliable encapsulants such as small interfering RNA (siRNA), plasmid DNA (pDNA), and cisplatin as a result of precisely tuned fabrication of nanocarriers, showing that this technology is paving the way for innovative strategies in cancer therapy nanofabrication, characterized by continuous production and high reproducibility. Finally, this review analyzes the technical, biological, and technological limitations that currently prevent this technology from becoming the standard.

Investigating the effectiveness of liposome-bacteriophage nanocomplex in killing Staphylococcus aureus using epithelial cell coculture models

Host cell invasion with strong antibiotics evading is a major feature of respiratory Staphylococcus aureus infections with severe recurrence. Bacteriophage (phage) therapy and design of liposomal phage to target intracellular pathogens have been described recently. The practicality for pulmonary delivery of liposomal phage, and how formulation compositions affecting the aerosolization and intracellular bacterial killing remain unexplored. In the present study, three commonly used phospholipids (SPC, EPC, and HSPC) were selected to investigate their ability for phage K nebulization and intracellular therapy in the form of liposome-phage nanocomplexes. The three lipid nanocarriers showed protection on phage K upon mesh nebulization and the pulmonary deposition efficiency was influenced by the lipid used. Moreover, the intracellular bacterial killing was strongly depended on the lipid types, where EPC-phage exhibited the best killing performance with no relapsing. Phage K with the aid of EPC liposomes was also observed to manage the tissue infection in a 3D spheroid model more effectively than other groups. Altogether, this novel EPC liposome-phage nanocomplex can be a promising formulation approach that enables inhalable phage to manage respiratory infections caused by bacteria strongly associated with human epithelial cells.

Microfluidic synthesis of lipid-based nanoparticles for drug delivery: recent advances and opportunities

Microfluidic technologies are revolutionizing the synthesis of nanoscale lipid particles and enabling new opportunities for the production of lipid-based nanomedicines. By harnessing the benefits of microfluidics for controlling diffusive and advective transport within microfabricated flow cells, microfluidic platforms enable unique capabilities for lipid nanoparticle synthesis with precise and tunable control over nanoparticle properties. Here we present an assessment of the current state of microfluidic technologies for lipid-based nanoparticle and nanomedicine production. Microfluidic techniques are discussed in the context of conventional production methods, with an emphasis on the capabilities of microfluidic systems for controlling nanoparticle size and size distribution. Challenges and opportunities associated with the scaling of manufacturing throughput are discussed, together with an overview of emerging microfluidic methods for lipid nanomedicine post-processing. The impact of additive manufacturing on current and future microfluidic platforms is also considered.

Integrated continuous manufacturing of inhalable remdesivir nanoagglomerate dry powders: Design, optimization and therapeutic potential for respiratory viral infections

While inhalable nanoparticle-based dry powders have demonstrated promising potential as next-generation respiratory medicines, erratic particle redispersibility and poor manufacturing reproducibility remain major hurdles hindering their translation from bench to bedside. We developed a one-step continuous process for fabricating inhalable remdesivir (RDV) nanoagglomerate dry powder formulations by integrating flash nanoprecipitation and spray drying. The nanosuspension formulation was optimized using a three-factor Box-Behnken design with a z-average particle size of 233.3 ± 2.3 nm and < 20% size change within six hours. The optimized inhalable nanoagglomerate dry powder formulation produced by spray drying showed adequate aqueous redispersibility (Sf/Si = 1.20 ± 0.01) and in vitro aerosol performance (mass median aerodynamic diameter of 3.80 ± 0.58 µm and fine particle fraction of 39.85 ± 10.16%). In A549 cells, RDV nanoparticles redispersed from the inhalable nanoagglomerate powders displayed enhanced and accelerated RDV cell uptake and negligible cytotoxicity at therapeutic RDV concentrations. No statistically significant differences were observed in the critical quality attributes of the inhalable nanoagglomerate powders produced from the continuous manufacturing and standalone batch modes. This work demonstrates the feasibility of large-scale continuous manufacturing of inhalable nanoagglomerate dry powder formulations, which pave the way for their clinical translation.

Evaluation of a static mixer as a new microfluidic method for liposome formulation

Introduction: Microfluidic formulation of liposomes has been extensively studied as a potential replacement for batch methods, which struggle with problems in scalability and difficulty in modulating conditions. Although microfluidic devices are considered to be able to combat these issues, an adequate replacement method has yet to be established. Methods: This paper examines the potential of a static mixer (SM) by comparing the encapsulation efficiency, loading, lamellarity, and user-friendliness with a commonly used microfluidic device, a staggered herringbone micromixer (SHM). Results: In both devices, it was found that as the initial lipid concentration increased, the particle size increased; however, the overall particle size was seen to be significantly larger in the liposomes prepared with SM. PDI remained significantly smaller in SM, however, signifying that better control of the particle size was accomplished in SM. In addition, the encapsulation efficiency was slightly smaller in SM compared to SHM, and in both devices, the values increased as the initial lipid concentration increased. The increase in encapsulation efficiencies was significantly smaller than that of the theoretical encapsulation efficiency, and this was found to be due to the increase in lamellarity as the initial lipid concentration increased. Discussion: In terms of user-friendliness, SM demonstrated significant advantages. The mixing elements could be taken out from the device, allowing for thorough cleaning of the element and device before and after experiments and ensuring experiments are conducted at virgin state in every round. Consequently, it was found that SM not only can produce uniformly distributed liposomes but has the potential to become a more practical method for liposome formulation with modifications in the mixing elements.

Microfluidic vortex focusing for high throughput synthesis of size-tunable liposomes

Control over vesicle size during nanoscale liposome synthesis is critical for defining the pharmaceutical properties of liposomal nanomedicines. Microfluidic technologies capable of size-tunable liposome generation have been widely explored, but scaling these microfluidic platforms for high production throughput without sacrificing size control has proven challenging. Here we describe a microfluidic-enabled process in which highly vortical flow is established around an axisymmetric stream of solvated lipids, simultaneously focusing the lipids while inducing rapid convective and diffusive mixing through application of the vortical flow field. By adjusting the individual buffer and lipid flow rates within the system, the microfluidic vortex focusing technique is capable of generating liposomes with precisely controlled size and low size variance, and may be operated up to the laminar flow limit for high throughput vesicle production. The reliable formation of liposomes as small as 27 nm and mass production rates over 20 g/h is demonstrated, offering a path toward production-scale liposome synthesis using a single continuous-flow vortex focusing device.

Erythromycin Formulations—A Journey to Advanced Drug Delivery

Erythromycin (ERY) is a macrolide compound with a broad antimicrobial spectrum which is currently being used to treat a large number of bacterial infections affecting the skin, respiratory tract, intestines, bones and other systems, proving great value from a clinical point of view. It became popular immediately after its discovery in 1952, due to its therapeutic effect against pathogens resistant to other drugs. Despite this major advantage, ERY exhibits several drawbacks, raising serious clinical challenges. Among them, the very low solubility in water and instability under acidic conditions cause a limited efficacy and bioavailability. Apart from this, higher doses promote drug resistance and undesirable effects. In order to overcome these disadvantages, during the past decades, a large variety of ERY formulations, including nanoparticles, have emerged. Despite the interest in ERY-(nano)formulations, a review on them is lacking. Therefore, this work was aimed at reviewing all efforts made to encapsulate ERY in formulations of various chemical compositions, sizes and morphologies. In addition, their preparation/synthesis, physico-chemical properties and performances were carefully analysed. Limitations of these studies, particularly the quantification of ERY, are discussed as well.