Formation of Fine Particles from Curcumin/PVP by the Supercritical Antisolvent Process with a Coaxial Nozzle

Degradable Multilayer Fabric Sensor with Wide Detection Range and High Linearity

Integration of multiple superior features into a single flexible pressure sensor would result in devices with greater versatility and utility. To apply the device to a variety of scenarios and solve the problem of accumulation of e-waste in the environment, it is highly desirable to combine degradability and wide-range linearity characteristics in a single device. Herein, we reported a degradable multilayer fabric (DMF) consisting of an ellipsoidal carbon nanotube (ECNT) and polyvinylpyrrolidone/cellulose acetate electrospun fibers (PEF). The alternative layer-by-layer stacking of the ECNT and PEF notably accelerates the sensitivity toward pressure. The optimized device demonstrated a sensitivity of 3.38 kPa-1 over a wide measurement range from 0.1 to 500 kPa, as well as great mechanical stability over 2000 cycles. A good degradation performance was confirmed by both Fourier transform infrared (FTIR) characterization and decomposition experiments in sodium hydroxide solution. The fabricated sensor is capable of precepting a variety of physiological scenarios including subtle arterial pulse, dancing training, walking postures, and accidental falls. This work throws light onto the fundamental understanding of the mechanical interfacial coupling in piezoresistive materials and provides possibilities for the design and development of on-demand wearable electronics.

Inhalable paclitaxel nanoagglomerate dry powders for lung cancer chemotherapy: Design of experiments-guided development, characterization and in vitro evaluation

Conventional intravenous chemotherapy for lung cancer frequently results in inefficient drug penetration into primary lung tumors and severe systemic toxicities. This study reports the development of inhalable paclitaxel (PTX) nanoagglomerate dry powders (PTX-NADP) for enhanced pulmonary delivery of PTX chemotherapy to lung tumors using full factorial Design of Experiments. PTX nanoparticles were fabricated by flash nanoprecipitation with the aid of N-polyvinylpyrrolidone (PVP) and curcumin (CUR) as stabilizer and co-stabilizer respectively, and subsequently agglomerated into inhalable dry powders via co-spray drying with methylcellulose. The optimized PTX-NADP formulation exhibited acceptable aqueous redispersibility (redispersibility index = 1.17 ± 0.02) into ∼ 150 nm nanoparticles and superb in vitro aerosol performance [mass median aerodynamic diameter (MMAD) = 1.69 ± 0.05 µm and fine particle fraction (FPF) of 70.89 ± 1.72 %] when dispersed from a Breezhaler® at 90 L/min. Notably, adequate aerosolization (MMAD < 3.5 µm and FPF > 40 %) of the optimized formulation was maintained when dispersed at reduced inspiratory flow rates of 30 - 60 L/min. Redispersed PTX nanoparticles from PTX-NADP demonstrated enhanced in vitro antitumor efficacy and cellular uptake in A549 lung adenocarcinoma cells without compromising tolerability of BEAS-2B normal lung epithelial cells towards PTX chemotherapy. These findings highlight the potential of inhaled PTX-NADP therapy to improve therapeutic outcomes for lung cancer patients with varying levels of pulmonary function impairment.

Modified Curcuminoid-Rich Extract Liposomal CRE-SDInhibits Osteoclastogenesis via the Canonical NF-κB Signaling Pathway

Curcuminoids, namely curcumin, demethoxycurcumin, and bisdemethoxycurcumin, are the major active compounds found in Curcuma longa L. (turmeric). Although their suppressive effects on bone resorption have been demonstrated, their pharmacokinetic disadvantages remain a concern. Herein, we utilized solid dispersion of a curcuminoid-rich extract (CRE), comprising such curcuminoids, to prepare CRE-SD; subsequently, we performed liposome encapsulation of the CRE-SD to yield liposomal CRE-SD. In vitro release assessment revealed that a lower cumulative mass percentage of CRE-SD was released from liposomal CRE-SD than from CRE-SD samples. After culture of murine RANKL-stimulated RAW 264.7 macrophages, our in vitro examinations confirmed that liposomal CRE-SD may impede osteoclastogenesis by suppressing p65 and IκBα phosphorylation, together with nuclear translocation and transcriptional activity of phosphorylated p65. Blind docking simulations showed the high binding affinity between curcuminoids and the IκBα/p50/p65 protein complex, along with many intermolecular interactions, which corroborated our in vitro findings. Therefore, liposomal CRE-SD can inhibit osteoclastogenesis via the canonical NF-κB signaling pathway, suggesting its pharmacological potential for treating bone diseases with excessive osteoclastogenesis.

Particle preparation of pharmaceutical compounds using supercritical antisolvent process: current status and future perspectives

The low aqueous solubility and subsequently slow dissolution rate, as well as the poor bioavailability of several active pharmaceutical ingredients (APIs), are major challenges in the pharmaceutical industry. In this review, the particle engineering approaches using supercritical carbon dioxide (SC CO₂) as an antisolvent are critically reviewed. The different SC CO₂-based antisolvent processes, such as the gas antisolvent process (GAS), supercritical antisolvent process (SAS), and a solution-enhanced dispersion system (SEDS), are described. The effect of process parameters such as temperature, pressure, solute concentration, nozzle diameter, SC CO₂ flow rate, solvent type, and solution flow rate on the average particle size, particle size distribution, and particle morphology is discussed from the fundamental perspective of the SAS process. The applications of the SAS process in different formulation approaches such as solid dispersion, polymorphs, cocrystallization, inclusion complexation, and encapsulation to enhance the dissolution rate, solubility, and bioavailability are critically reviewed. This review highlights some areas where the SAS process has not been adequately explored yet. This review will be helpful to researchers working in this area or planning to explore SAS process to particle engineering approaches to tackle the challenge of low solubility and subsequently slow dissolution rate and poor bioavailability.

Vapor–Liquid Equilibria of Quaternary Systems of Interest for the Supercritical Antisolvent Process

In the Supercritical Antisolvent process (SAS), the thermodynamic behavior of complex multicomponent systems can influence the particles’ morphology. However, due to the limited thermodynamic data for multicomponent systems, the effect of solutes is often neglected, and the system is considered as pseudo-binary. It has been demonstrated that the presence of a solute can significantly influence the thermodynamic behavior of the system. In particular, when the SAS process is adopted for the production of drug/polymer coprecipitated microparticles, the effect of both the drug and the polymer in the solvent/CO2 mixture should be considered. In this work, the effect of polyvinylpyrrolidone (PVP), used as the carrier, and of the liposoluble vitamins menadione (MEN) and α-tocopherol (TOC), as model drugs, was investigated as a deviation from the fundamental thermodynamic behavior of the DMSO/CO2 binary system. Vapor–liquid equilibria (VLE) were evaluated at 313 K, with a PVP concentration in the organic solution equal to 20 mg/mL. The effect of the presence of PVP, MEN, and TOC on DMSO/CO2 VLE at 313 K was studied; furthermore, the effect of PVP/MEN and PVP/TOC, at a polymer/drug ratio of 5/1 and 3/1, was determined. Moreover, SAS precipitation experiments were performed at the same polymer/drug ratios using a pressure of 90 bar. Thermodynamic studies revealed significant changes in phase behavior for DMSO/CO2/PVP/TOC and DMSO/CO2/PVP/MEN systems compared to the binary DMSO/CO2 system. From the analysis of the effect of the presence of a single compound on the binary system VLE, it was noted that PVP slightly affected the thermodynamic behavior of the system. In contrast, these effects were more evident for the DMSO/CO2/TOC and DMSO/CO2/MEN systems. SAS precipitation experiments produced PVP/MEN and PVP/TOC microparticles, and the obtained morphology was justified considering the quaternary systems VLE.

Enhancement of Release and Solubility of Curcumin from Electrospun PEO-EC-PVP Tripolymer-Based Nanofibers: A Study on the Effect of Hydrogenated Castor Oil

This study reveals the state-of-the-art fabrication of a tripolymer-based electrospun nanofiber (NF) system to enhance the release, solubility, and transdermal penetration of curcumin (Cur) with the aid of in situ release of infused castor oil (Co). In this regard, Cur-loaded Co-infused polyethylene oxide (PEO), ethyl cellulose (EC), and polyvinyl pyrrolidone (PVP) tripolymer-based NF systems were developed to produce a hybridized transdermal skin patch. Weight percentages of 1-4% Cur and 3-10% of Co were blended with PEO-EC-PEO and PEO-EC-PVP polymer systems. The prepared NFs were characterized by SEM, TEM, FT-IR analysis, PXRD, differential scanning calorimetry (DSC), and XPS. Dialysis membranes and vertical Franz diffusion cells were used to study the in vitro drug release and transdermal penetration, respectively. The results indicated that maintaining a Cur concentration of 1-3 wt % with 3 wt % Co in both PEO-EC-Co-Cur@PEO and PEO-EC-Co-Cur@PVP gave rise to nanofibers with lowered diameters (144.83 ± 48.05-209.26 ± 41.80 nm and 190.20 ± 59.42-404.59 ± 45.31 nm). Lowered crystallinity observed from the PXRD patterns and the disappearance of exothermic peaks corresponding to the melting point of Cur suggested the formation of an amorphous NF structure. Furthermore, the XPS data revealed that the Cur loading will possibly take place at the inner interface of PEO-EC-Co-PEO and PEO-EC-Co-PVP NFs rather than on the surface. The beneficiary role of Co on the release and dermal penetration of Cur was further confirmed from the respective release data which indicated that PEO-EC-Co-Cur@PEO would lead to a rapid release (4-5 h), while PEO-EC-Co-Cur@PVP would lead to a sustained release over a period of 24 h in the presence of Co. Transdermal penetration of the released Cur was further evidenced with the development of color in the receiver compartment of the diffusion cell. DPPH results further corroborated that a sustained antioxidant activity is observed in the released Cur where the free-radical scavenging activity is intact even after subjecting to an electrospinning process and under extreme freeze-thaw conditions.

Curcumin-Loaded Liposome Preparation in Ultrasound Environment under Pressurized Carbon Dioxide

Curcumin-loaded liposomes were prepared using a supercritical carbon dioxide (SCCO2)−ultrasound environment system. The experiments were performed at temperatures of 40−70 °C and pressures of 10−25 MPa in a batch system with ultrasonication for 60 min. Transmission electron microscopy (TEM) images revealed liposome products with spherical morphologies and diameters of <100 nm. Dynamic light scattering (DLS) analysis indicated that the curcumin-loaded liposome nanosuspension exhibited good stability. Changing the operating conditions influenced the amount of liposome-encapsulated curcumin; as the operating temperature or pressure increased, the diameter of the liposome products and the amount of liposome-encapsulated curcumin increased and decreased, respectively. Herein, we described an innovative and practical organic-solvent-free method for generating liposomes from phospholipids.

Reduced-Pressure Process for Fabricating Tea Tree Oil-Polyvinylpyrrolidone Electrospun Fibers

Electrospun fibers containing tea tree oil (TTO) can be explored for practical applications due to the antimicrobial and anti-inflammatory activities of TTO. Considering that there are potentially toxic components in TTO, it is necessary to eliminate or reduce its content in the preparation process of TTO-doped electrospun fibers. In this work, electrospun TTO-PVP (polyvinylpyrrolidone) fibers containing an 18.18 wt.% decreased content of 1,8-Cineole were successfully fabricated by intense evaporation of a self-made reduced-pressure electrospinning (RP-ES) setup (as low as 94.4 kPa). In addition, such intense evaporation led to a morphology change, where a typical average fiber diameter increased from 0.831 to 1.148 μm, fewer and smaller beads in fibers, along with a rougher and grooves fiber surface. These morphology changes allowed Terpinen-4-ol to remain in the fiber for a more extended period. In addition, RP-ES proved the possibility for intense evaporation and continuous vapor removal by continuously environmental vacuum pumping of electrospinning.

Characterization of excipients to improve pharmaceutical properties of sirolimus in the supercritical anti-solvent fluidized process

Enhanced drug release and bioavailability of poorly soluble active pharmaceutical ingredient (API) can be achieved via a fluidized bed coating integrated with supercritical anti-solvent (SAS-FB) - a process of precipitating drug particles onto carrier granules. However, in the absence of excipients, SAS-FB often results in crystalline of the API on the surface of carriers, limiting the improvement of pharmaceutical properties. Co-processing with excipients is considered an effective approach to improve drug release in the SAS-FB process. Our study used sirolimus, an immune suppressive agent, as the model API to characterize excipients for their effect on pharmaceutical properties in the SAS-FB process. We show that co-precipitation of excipients and sirolumus impacts on carrier specific surface area and drug yield. Among the tested excipients, formulation containing polyvinylpyrrolidone K30 achieved the highest drug yield. Importantly, compared with Rapamune® tablet, our optimized formulation displayed a superior in vivo oral bioavailability by 3.05-fold in Sprague-Dawley rats and 3.99-fold in beagle dogs. A series of characterization of the processed API was performed to understand the mechanism by which excipients contributed to drug dissolution properties. Our study provides a useful guidance for the use of excipients in the SAS-FB technology to improve pharmaceutical properties of sirolimus and other poorly soluble drugs.

Control and Preparation of Quaternized Chitosan and Carboxymethyl Chitosan Nanoscale Polyelectrolyte Complexes Based on Reactive Flash Nanoprecipitation

Nanoscale polyelectrolyte complex materials have been extensively investigated for their promising application in protocell, drug carriers, imaging, and catalysis. However, the conventional preparation approach involving positive and negative polyelectrolytes leads to large size, wide size distribution, instability, and aggregation due to the nonhomogeneous mixing process. Herein, we employ reactive flash nanoprecipitation (RFNP) to control the mixing and preparation of the nanoscale polyelectrolyte complex. With RFNP, homogeneous mixing complexation between oppositely charged chitosan derivatives could be achieved, resulting in stable nanoscale complexes (NCs) with controllable size and narrow size distribution. The smallest size of NCs is found at specific pH due to the maximum attraction of positive and negative molecules of chitosan. The size can be modulated by altering the volumetric flow rates of inlet streams, concentration, and charge molar ratio of two oppositely charged chitosan derivatives. The charge molar ratio is also tuned to create NCs with positive and negative shells. There is no significant variation in the size of NCs produced at different intervals of time. This method allows continuous and tunable NC production and could have the potential for fast, practical translation.

Effect of the Carrier on the Coprecipitation of Curcumin through Supercritical-Assisted Atomization

In this paper, composite systems containing curcumin (CUR) were prepared through supercritical-assisted atomization (SAA), using different carriers. Curcumin is particularly interesting in the pharmaceutical and nutraceutical fields for its antioxidant, antitumoral, and anti-inflammatory properties. However, its therapeutic effect on human health is restricted by its poor water solubility and low dissolution rate, limiting its absorption after its oral administration. To increase the dissolution rate and then the bioavailability of the active compound, CUR was coprecipitated with polymeric, i.e., polyvinylpyrrolidone (PVP) and dextran (DXT), and not polymeric, i.e., hydroxypropyl-β-cyclodextrin (HP-β-CD), carriers. The effects of some operating parameters, namely the concentration of solutes in solution and the active compound/carrier ratio, on the morphology and the particle size distribution of the powders were investigated. Submicrometric particles were produced with all the carriers. Under the best operating conditions, the mean diameters ± standard deviation were equal to 0.69 ± 0.20 μm, 0.40 ± 0.13 μm, and 0.81 ± 0.25 μm for PVP/CUR, DXT/CUR, and HP-β-CD/CUR, respectively. CUR dissolution rates from coprecipitated particles were significantly increased in the case of all the carriers. Therefore, the results are exciting from a pharmaceutical and nutraceutical point of view, to produce supplements containing curcumin, but assuring a high dissolution rate and bioavailability and, consequently, a more effective therapeutic effect.

Applications of Supercritical Anti-Solvent Process in Preparation of Solid Multicomponent Systems

Solid multicomponent systems (SMS) are gaining an increasingly important role in the pharmaceutical industry, to improve the physicochemical properties of active pharmaceutical ingredients (APIs). In recent years, various processes have been employed for SMS manufacturing. Control of the particle solid-state properties, such as size, morphology, and crystal form is required to optimize the SMS formulation. By utilizing the unique and tunable properties of supercritical fluids, supercritical anti-solvent (SAS) process holds great promise for the manipulation of the solid-state properties of APIs. The SAS techniques have been developed from batch to continuous mode. Their applications in SMS preparation are summarized in this review. Many pharmaceutical co-crystals and solid dispersions have been successfully produced via the SAS process, where the solid-state properties of APIs can be well designed by controlling the operating parameters. The underlying mechanisms on the manipulation of solid-state properties are discussed, with the help of on-line monitoring and computational techniques. With continuous researching, SAS process will give a large contribution to the scalable and continuous manufacturing of desired SMS in the near future.

Supercritical Antisolvent Process for Pharmaceutical Applications: A Review

The supercritical antisolvent (SAS) technique has been widely employed in the biomedical field, including drug delivery, to obtain drug particles or polymer-based systems of nanometric or micrometric size. The primary purpose of producing SAS particles is to improve the treatment of different pathologies and to better the patient’s compliance. In this context, many active compounds have been micronized to enhance their dissolution rate and bioavailability. Aiming for more effective treatments with reduced side effects caused by drug overdose, the SAS polymer/active principle coprecipitation has mainly been proposed to offer an adequate drug release for specific therapy. The demand for new formulations with reduced side effects on the patient’s health is still growing; in this context, the SAS technique is a promising tool to solve existing issues in the biomedical field. This updated review on the use of the SAS process for clinical applications provides useful information about the achievements, the most effective polymeric carriers, and parameters, as well as future perspectives.