Production of menthol-loaded nanoparticles by solvent displacement

Computational-Aided Approach for the Optimization of Microfluidic-Based Nanoparticles Manufacturing Process

In the last few years, the microfluidic production of nanoparticles (NPs) is becoming a promising alternative to conventional industrial approaches (e.g., nanoprecipitation, salting out, and emulsification-diffusion) thanks to the production efficiency, low variability, and high controllability of the production parameters. Nevertheless, the development of new formulations and the switching of the production process toward microfluidic platforms requires expensive and time-consuming number of experiments for the tuning of the formulation to obtain NPs with specific morphological and functional characteristics. In this work, we developed a computational fluid dynamic pipeline, validated through an ad hoc experimental strategy, to reproduce the mixing between the solvent and anti-solvent (i.e., acetonitrile and TRIS-HCl, respectively). Moreover, beyond the classical variables able to describe the mixing performances of the microfluidic chip, novel variables were described in order to assess the region of the NPs formation and the changing of the amplitude of the precipitation region according to different hydraulic conditions. The numerical approach proved to be able to capture a progressive reduction of the nanoprecipitation region due to an increment of the flow rate ratio; in parallel, through the experimental production, a progressive increment of the NPs size heterogeneity was observed with the same fluid dynamic conditions. Hence, the preliminary comparison between numerical and experimental evidence proved the effectiveness of the computational strategy to optimize the NPs manufacturing process.

Flash nanoprecipitation assisted self-assembly of ionizable lipid nanoparticles for nucleic acid delivery

Ionizable lipid nanoparticles (LNPs) have emerged as a powerful tool for the intracellular delivery of nucleic acids. Following the recent success of LNP-based siRNA therapeutics and mRNA vaccines, the use of ionizable lipids for nucleic acid delivery has tremendously increased. Here, we introduce a flash nanoprecipitation (FNP) approach using the confined impingement (CIJ) mixer to stably self-assemble ionizable LNPs. To validate this approach, we employed three clinically relevant LNP formulations containing SM102, ALC0315, and DLin-MC3-DMA as ionizable lipids. FNP-assembled LNPs showed >95% encapsulation efficiency of mRNA and siRNA payloads and particle sizes below 150 nm. SM102 or ALC0315 LNPs demonstrated efficient delivery of mRNA into immune cells in vitro and to lymphoid organs in vivo, whereas Dlin-MC3-DMA LNPs allowed effective intracellular siRNA delivery with great functional ability. The FNP technique could economically produce LNPs in smaller volumes that are highly suitable for the discovery phase.

Encapsulation of mint essential oil: Techniques and applications

Mint essential oil (MEO) is an outstanding antibacterial and antioxidant agent, that can be considered as a promising natural preservative, flavor, insecticide, coolant, and herbal medicine. However, the low solubility and volatility of MEO limits its extensive applications. In order to utilize MEO in different products, it is essential to develop treatments that can overcome these limitations. More recently, encapsulation technology has been developed as a promising method to overcome the shortcomings of MEO. In which, sensitive compounds such as essential oils (EOs) are entrapped in a carrier to produce micro or nanoparticles with increased stability against environmental conditions. Additionally, encapsulation of EOs makes transportation and handling easier, reduces their volatility, controls their release and consequently improves the efficiency of these bioactive compounds and extends their industrial applications. Several encapsulation techniques, such as emulsification, coacervation, ionic gelation, inclusion complexation, spray drying, electrospinning, melt dispersion, melt homogenization, and so on, have been emerged to improve the stability of MEO. These encapsulated MEOs can be also used in a variety of food, bioagricultural, pharmaceutical, and health care products with excellent performance. Therefore, this review aims to summarize the physicochemical and functional properties of MEO, recent advances in encapsulation techniques for MEO, and the application of micro/nanocapsulated MEO in different products.

Continuous Nanoprecipitation of Polycaprolactone in Additively Manufactured Micromixers

The polymeric ouzo effect is an energy-efficient and robust method to create nanoparticles with biologically degradable polymers. Usually, a discontinuous or semi-continuous process is employed due to its low technical effort and the fact that the amount of dispersions needed in a laboratory is relatively small. However, the number of particles produced in this method is not enough to make this process economically feasible. Therefore, it is necessary to improve the productivity of the process and create a controllable and robust continuous process with the potential to control parameters, such as the particle size or surface properties. In this study, nanoparticles were formulated from polycaprolactone (PCL) in a continuous process using additively manufactured micromixers. The main goal was to be able to exert control on the particle parameters in terms of size and zeta potential. The results showed that particle size could be adjusted in the range of 130 to 465 nm by using different flow rates of the organic and aqueous phase and varying concentrations of PCL dissolved in the organic phase. Particle surface charge was successfully shifted from a slightly negative potential of −14.1 mV to a negative, positive, or neutral value applying the appropriate surfactant. In summary, a continuous process of nanoprecipitation not only improves the cost of the method, but furthermore increases the control over the particle’s parameters.

Development of Advanced Textile Finishes Using Nano-Emulsions from Herbal Extracts for Organic Cotton Fabrics

The development of textile finishing with improved functional properties has been a growing interest among industry and scientists worldwide. The recent global pandemic also enhanced the awareness amongst many toward improved hygiene and the use of antimicrobial textiles. Generally, natural herbal components are known to possess antimicrobial properties which are green and eco-friendly. This research reports a novel and innovative method of developing and optimising nano-emulsions using two combinations of herbal extracts produced from Moringa Oleifera, curry leaf, coconut oil (nano-emulsion 1) and other using Aegle marmelos with curry leaf and coconut oil (nano-emulsion 2). Nano-emulsions were optimised for their pH, thermal stability, and particle size, and percentage add-on. Organic cotton fabrics (20 and 60 gsm) were finished with nano-emulsions using continuous and batch processes and characterised for their surface morphology using scanning electron microscopy, energy dispersive X-ray (EDX) analysis and Fourier transform infrared spectroscopy (FTIR) analysis. The finished fabrics were evaluated for their Whiteness Index, assessed for antimicrobial resistance against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) using AATCC 100 and 147 methods. In addition, fabrics were assessed for their antifungal efficacy (AATCC 30), tensile strength and air permeability. Results suggested that finished organic fabrics with nano-emulsions had antimicrobial resistance, antifungal, wash fastness after 20 washing cycles, and sufficient strength. This novel finishing method suggests that organic cotton fabrics treated with nano-emulsions can be used as a durable antimicrobial textile for healthcare and hygiene textiles.

Bio-Functional Textiles: Combining Pharmaceutical Nanocarriers with Fibrous Materials for Innovative Dermatological Therapies

In the field of pharmaceutical technology, significant attention has been paid on exploiting skin as a drug administration route. Considering the structural and chemical complexity of the skin barrier, many research works focused on developing an innovative way to enhance skin drug permeation. In this context, a new class of materials called bio-functional textiles has been developed. Such materials consist of the combination of advanced pharmaceutical carriers with textile materials. Therefore, they own the possibility of providing a wearable platform for continuous and controlled drug release. Notwithstanding the great potential of these materials, their large-scale application still faces some challenges. The present review provides a state-of-the-art perspective on the bio-functional textile technology analyzing the several issues involved. Firstly, the skin physiology, together with the dermatological delivery strategy, is keenly described in order to provide an overview of the problems tackled by bio-functional textiles technology. Secondly, an overview of the main dermatological nanocarriers is provided; thereafter the application of these nanomaterial to textiles is presented. Finally, the bio-functional textile technology is framed in the context of the different dermatological administration strategies; a comparative analysis that also considers how pharmaceutical regulation is conducted.

Application of flash nanoprecipitation to fabricate poorly water-soluble drug nanoparticles

Nanoparticles are considered to be a powerful approach for the delivery of poorly water-soluble drugs. One of the main challenges is developing an appropriate method for preparation of drug nanoparticles. As a simple, rapid and scalable method, the flash nanoprecipitation (FNP) has been widely used to fabricate these drug nanoparticles, including pure drug nanocrystals, polymeric micelles, polymeric nanoparticles, solid lipid nanoparticles, and polyelectrolyte complexes. This review introduces the application of FNP to produce poorly water-soluble drug nanoparticles by controllable mixing devices, such as confined impinging jets mixer (CIJM), multi-inlet vortex mixer (MIVM) and many other microfluidic mixer systems. The formation mechanisms and processes of drug nanoparticles by FNP are described in detail. Then, the controlling of supersaturation level and mixing rate during the FNP process to tailor the ultrafine drug nanoparticles as well as the influence of drugs, solvent, anti-solvent, stabilizers and temperature on the fabrication are discussed. The ultrafine and uniform nanoparticles of poorly water-soluble drug nanoparticles prepared by CIJM, MIVM and microfluidic mixer systems are reviewed briefly. We believe that the application of microfluidic mixing devices in laboratory with continuous process control and good reproducibility will be benefit for industrial formulation scale-up.

Overcoming the Limits of Flash Nanoprecipitation: Effective Loading of Hydrophilic Drug into Polymeric Nanoparticles with Controlled Structure

Flash nanoprecipitation (FNP) is a widely used technique to prepare particulate carriers based on various polymers, and it was proven to be a promising technology for the industrial production of drug loaded nanoparticles. However, up to now, only its application to hydrophobic compounds has been deeply studied and the encapsulation of some strongly hydrophilic compounds, such as caffeine, remains a challenge. Caffeine loaded poly-ε-caprolactone (PCL) nanoparticles were produced in a confined impinging jet mixer using acetone as the solvent and water as the antisolvent. Caffeine was dissolved either in acetone or in water to assess the effects of two different process conditions. Nanoparticles properties were assessed in terms of loading capacity (LC%), encapsulation efficiency (EE%), and in vitro release kinetics. Samples were further characterized by dynamic light scattering, scanning electron microscopy, X-ray photo electron spectroscopy, and infrared spectroscopy to determine the size, morphology, and structure of nanoparticles. FNP was proved an effective technique for entrapping caffeine in PCL and to control its release behavior. The solvent used to solubilize caffeine influences the final structure of the obtained particles. It was observed that the active principle was preferentially adsorbed at the surface when using acetone, while with water, it was embedded in the matrix structure. The present research highlights the possibility of extending the range of applications of FNP to hydrophilic molecules.

Functionalization of Cotton Fabrics with Polycaprolactone Nanoparticles for Transdermal Release of Melatonin

Drug delivery by means of transdermal patches raised great interest as a non-invasive and sustained therapy. The present research aimed to design a patch for transdermal delivery of melatonin, which was encapsulated in polycaprolactone (PCL) nanoparticles (NPs) by employing flash nanoprecipitation (FNP) technique. Melatonin-loaded PCL nanoparticles were successfully prepared with precise control of the particle size by effectively tuning process parameters. The effect of process parameters on the particle size was assessed by dynamic light scattering for producing particles with suitable size for transdermal applications. Quantification of encapsulated melatonin was performed by mean of UV spectrophotometry, obtaining the estimation of encapsulation efficiency (EE%) and loading capacity (LC%). An EE% higher than 80% was obtained. Differential scanning calorimetry (DSC) analysis of NPs was performed to confirm effective encapsulation in the solid phase. Cotton fabrics, functionalized by imbibition with the nano-suspension, were analyzed by scanning electron microscopy to check morphology, adhesion and distribution of the NPs on the surface; melatonin transdermal release from the functionalized fabric was performed via Franz’s cells by using a synthetic membrane. NPs were uniformly distributed on cotton fibres, as confirmed by SEM observations; the release test showed a continuous and controlled release whose kinetics were satisfactorily described by Baker–Lonsdale model.