Antibiotic resistance is a major healthcare challenge globally, and the development of antimicrobial therapies and modes for their targeted delivery is not keeping pace. Many promising antimicrobial candidates are abandoned early in discovery because of their high hydrophobicity and low bioavailability, limiting their evaluation in preclinical models. Therefore, developing drug delivery technologies compatible with potent yet hydrophobic antimicrobial candidates could revitalize a stagnant antibiotic pipeline. Herein, we combined Pressurized Gas eXpanded liquid technology (PGXTEC) with supercritical adsorptive precipitation to load and subsequently deliver poorly water-soluble antimicrobial compounds directly to an infected wound. PGXTEC-processed cross-linked sodium alginate compressed into disks exhibits extremely high specific surface area (∼160 m2/g) to enable drug impregnation and effective exudate absorption. As proof of concept, PGXTEC alginate disks loaded with fusidic acid (FA) suppressed bacterial growth in full thickness wounds infected with methicillin-resistant Staphylococcus aureus (MRSA); furthermore, PGXTEC disks loaded with tigecycline (TIG), typically considered a bacteriostatic antibiotic when used conventionally against MRSA, sterilized wounds with bactericidal activity even at low overall drug doses relative to the conventionally used therapeutic doses for intravenous TIG. PGXTEC combined with adsorptive precipitation is thus a flexible platform technology to deliver hydrophobic antibiotics in a bioavailable format, offering the potential to revive classes of antimicrobial compounds that are excluded early in the discovery process due to low water solubility and incompatible modes of delivery.

Current anti‐fibrotic therapeutics for idiopathic pulmonary fibrosis (IPF) slow disease progression but are non‐curative and have systemic side effects, promoting interest in therapies that can repolarize macrophages away from their pro‐fibrotic phenotype. While yeast beta‐glucan (YBG) offers therapeutic potential in reprogramming macrophages toward an anti‐fibrotic phenotype, YBG processing must be optimized to promote inhalability while preserving its biological activity. Herein, the biological and inhalation performance of YBG processed via Pressurized Gas eXpanded liquids technology (PGX TEC ‐YBG) relative to conventionally spray‐dried YBG (SD‐YBG) is compared. The significantly smaller size and lower density of PGX TEC ‐YBG relative to SD‐YBG result in a smaller aerodynamic diameter (3–4 µm) and double the fine particle fraction in cascade impaction studies, variables correlated with improved inhalability and thus deposition in the distal regions of the lung. Correspondingly, PGX TEC ‐YBG shows an approximately double phagocytic index in vitro and enhanced suppression of CD206 expression and arginase‐1 activity, lower levels of macrophage stress, and comparable capacity for promoting pro‐inflammatory cytokine release in ex vivo murine precision cut lung slices relative to SD‐YBG. These findings highlight PGX TEC ‐YBG's utility as a promising inhalable therapeutic that can offer improved delivery to the disease site while maintaining strong biological anti‐fibrotic effects and reduced systemic toxicity.

A dried, homogeneous porous composite containing poly(lactic-co-glycolic acid) nanoparticles (PLGA-NP) entrapped in a sodium alginate (SA) aerogel matrix was developed using the Pressurized Gas-eXpanded liquid Technology (PGXTEC) and compared to the same material dried by lyophilization. The size and stability of PLGANP in all stages of the processes were studied using dynamic light scattering and Field Emission Scanning Electron Microscopy. The morphology of the composites was investigated using helium ion microscopy, and fluorescence confocal microscopy. A fluorescently labeled dextran analogue (Tetramethylrhodamine Dextran, TMRD) as model for macromolecular drugs was loaded onto PLGA-NP and processed into PGXTEC-processed and freeze-dried composites. The release kinetics of TMRD from composites were measured and compared with unprocessed PLGA-NP. The results revealed that the processing of PLGA-NP using the PGXTEC expanded the particles leading to porous structures that facilitate the release of encapsulated macromolecules. Both composites prepared by PGXTEC or lyophilisation showed an initial burst release of TMRD in HEPES buffer solution in the first 8 h, reaching up to 8 % and 22 %, respectively. The PGXTEC processed composite outperformed the lyophilized composite for the total cumulative TMRD release after 400 h reaching 100 % release, while the lyophilized composite reached a plateau of about 32.7 %. The results suggest that PGXTEC-processed PLGA-NP entrapped in a SA matrix forming a PLGA-NP/SA composite have potential for delivery of macromolecular drugs such as peptides and proteins.

Pressurized Gas eXpanded (PGX) Liquid Technology precipitates and dries biopolymers using CO2-expanded organic solvents, producing open-porous materials with micro- and nanostructures. This study investigated the concentration of whey proteins from sweet whey liquid using PGX Technology as a single-step process at different scales and mass flow rate ratios (theta(PGX)) of PGX fluid (CO2+Ethanol) to sweet whey liquid. The PGX process efficiently removed >50% dwb lactose and lipids from the feedstock, forming a whey protein concentrate (PGX-W, >= 45% protein dwb) consisting mainly of beta-lactoglobulin, alpha-lactalbumin, and bovine serum albumin. At low theta PGX, PGX-W had high protein concentrations (50% dwb), with reduced solvent effects on protein secondary structure. At high theta(PGX), PGX-W contained 14% dwb lactose, higher than the <5% dwb obtained at lower flow rates and had finer morphologies (tens of nm) with increased specific surface area (13-29 m(2)/g). Resulting PGXW powders were free-flowing with low bulk density (35-74 g/L) and high-water solubility (>= 80%).

Pressurized Gas eXpanded (PGX) liquid technology is a scalable platform technology that simultaneously purifies, micronizes and dries aqueous solutions of biopolymers into fine structured open porous materials with unique morphologies using carbon dioxide (CO2) and ethanol at mild temperatures. The objective of this study was to investigate the effect of several PGX processing parameters on the physicochemical properties of sodium alginate (SA), a water-soluble polysaccharide from brown algae. PGX-processed SA (PGX-SA) had an open porous structure with a delicate network of fibrils, compared to the irregular shaped crystal-like non-porous particles of the raw SA dried using a conventional process. Upon PGX processing, the specific surface area was increased by more than 90 times compared to the raw SA. The use of low concentration (1.0% w/w) of the SA aqueous solution as the feed material and low ethanol flow rate (15 g/min), together with the mass flow rate ratio of 1:3.75:1.25 of aqueous solution:ethanol:CO2 resulted in a specific surface area of 164.5 m2/g of the PGX-SA. The PGX process shows great potential for simultaneously purifying and drying high molecular weight biopolymers into porous morphologies with large specific surface area for bioactive delivery systems in food, cosmetic and pharmaceutical applications.

Supercritical adsorptive precipitation (SAP) can be employed to load hydrophobic bioactives onto aerogels formed using the Pressurized Gas eXpanded liquid (PGX) Technology to prepare novel delivery systems. The objective of this study was to investigate the effects of SAP parameters on the coenzyme-Q10 (CoQ10) loading onto PGX-processed sodium alginate (PGX-SA) and its physicochemical properties. Within the ranges tested, higher recirculation time (50 min) and flow rate (262 mL/min), lower pressure (200 bar), and higher surface area biopolymer resulted in higher CoQ10 loading (46.9 +/- 3.0% w/w). Helium ion microscopy revealed a rather uniform coating of PGX-SA fibrils, covering the porous structure. Thermal and crystallinity analyses demonstrated a decrease in CoQ10 crystallinity. CoQ10-loaded PGX-SA suspension in water remained stable for 50 days at 4 degrees C. These findings demonstrate the potential of PGX Technology combined with SAP for developing delivery systems for hydrophobic bioactives to increase water dispersibility and suspension stability, which can boost their bioavailability.

Enzymes are natural catalysts capable of catalyzing specific reactions and versatile enough for widespread applications in the industry. To preserve the enzyme’s activity, it is essential to isolate and dry them from aqueous solutions without degrading their structure or making their active sites inaccessible. The Pressurized Gas eXpanded (PGX) liquid technology is a novel process that was successfully used to dry, purify, and micronize various biopolymers from aqueous solution. In this process, a pressurized mixture of CO 2 and ethanol (the PGX liquid) at mild temperature is used as the drying medium generating open-porous structures and particles of low bulk density and large specific surface area (SSA). Since the PGX technology has not been previously used to process enzymes, this study was conducted to investigate if the PGX technology could be used for drying enzymes and if the PGX enzymes were still active once they were rehydrated. Lysozyme was selected as the model enzyme tested in this study. Lysozyme is present in egg whites and has antimicrobial activity, making it suitable to be used in conjunction with other bioproducts to confer longer shelf life. Dried purified Lysozyme was purchased (Sigma-Aldrich), rehydrated in reverse osmosis water and then PGX dried at 10.0 MPa and 40 °C using a flow rate ratio of 10:30:10 g/min of aqueous solution:ethanol:CO 2 . The resulting particles were evaluated for their bulk density, SSA (BET method), morphology (Helium Ion Microscopy, HiM), chemical modifications (FTIR), and enzymatic activity. After PGX drying, the bulk density of lysozyme was reduced from 3.5 (±0.19) × (±0.15)×10 -2 g/mL were obtained with a lysozyme activity of ca. 2,205 ± 226 Units/mg of composite. However, a reduction in the surface area was observed compared with PGX processed sodium alginate, which could be a result of the lysozyme partially covering the porous structure of sodium alginate. This study established that PGX is a preferred technology to dry enzymes, such as lysozyme, because it not only retains but also increases the enzymatic activity of the commercially available product by reducing the particle size and increasing surface area. Additionally, PGX can also be applied to composite preparation by simultaneously drying enzymes and polysaccharides, allowing the development of formulations and novel products consisting of a natural carrier with antimicrobial properties.

The delivery of poorly water-soluble bioactives, including active pharmaceutical ingredients (API) and nutraceutical components is of great interest for existing drugs and new drug developments, cosmetic formulations, functional foods and nutraceuticals. This article presents a novel patented technology called PGX Technology, which utilizes pressurized gas expanded (PGX) liquids to dry, micronize, purify and functionalize water-soluble polymers. PGX Technology can generate open-porous nanostructured polymer carriers composed of one or several water-soluble polymers forming powders, granules, nano-fibrils, aerogels and exfoliated nano-composites with specific surface areas (SSA) ranging from tens to several hundred m2/g. Such mesoporous water-soluble carrier systems can be impregnated with a bioactive by means of adsorptive precipitation, utilizing supercritical carbon dioxide, leading to the uniform deposition of nano-scale particles (<120 nm) throughout the porous matrix, forming a bioactive-polymer complex, for example coenzyme Q10 on β-glucan (CoQ10-iBG). A nano-dispersion of CoQ10 is formed when such CoQ10-iBG complex is dissolved in water, which is stable over 6 months at room temperature. The bioavailability of the CoQ10-iBG complex tested in rats compared favorably with a positive control (CoQ10 in triolein) and a commercial CoQ10-cyclodextrin complex.

While the benefits of both hydrogels and drug delivery to enhance wound healing have been demonstrated, the highly hydrophilic nature of hydrogels creates challenges with respect to the effective loading and delivery of hydrophobic drugs beneficial to wound healing. Herein, we utilize pressurized gas expanded liquid (PGX) technology to produce very high surface area (similar to 200 m(2)/g) alginate scaffolds and describe a method for loading the scaffolds with ibuprofen (via adsorptive precipitation) and crosslinking them (via calcium chelation) to create a hydrogel suitable for wound treatment and hydrophobic drug delivery. The high surface area of the PGX-processed alginate scaffold facilitates >8 wt% loading of ibuprofen into the scaffold and controlled in vitro ibuprofen release over 12-24 h. In vivo burn wound healing assays demonstrate significantly accelerated healing with ibuprofen-loaded PGX-alginate/calcium scaffolds relative to both hydrogel-only and untreated controls, demonstrating the combined benefits of ibuprofen delivery to suppress inflammation as well as the capacity of the PGX-alginate/calcium hydrogel to maintain wound hydration and facilitate continuous calcium release to the wound. The use of PGX technology to produce highly porous scaffolds with increased surface areas, followed by adsorptive precipitation of a hydrophobic drug onto the scaffolds, offers a highly scalable method of creating medicated wound dressings with high drug loadings. Statement of Significance While medicated hydrogel-based wound dressings offer clear advantages in accelerating wound healing, the inherent incompatibility between conventional hydrogels and many poorly water-soluble drugs of relevance in wound healing remains a challenge. Herein, we leveraged supercritical fluids-based strategies to both process and subsequently impregnate alginate, followed by post-crosslinking to form a hydrogel, to create a very high surface area alginate hydrogel scaffold loaded with high hydrophobic drug contents (here, >8 wt% ibuprofen) without the need for any pore-forming additives. The impregnated scaffolds significantly accelerated burn wound healing while also promoting regeneration of the native skin morphology. We anticipate this approach can be leveraged to load clinically-relevant and highly bioavailable dosages of hydrophobic drugs in hydrogels for a broad range of potential applications. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The Pressurized Gas eXpanded (PGX) liquid technology was developed for simultaneously drying and purifying high molecular weight biopolymers, resulting in nano/micro-sized powders with large surface areas that can be loaded with various bioactives. The preparation of PGX-dried gum arabic (GA) and its loading by adsorptive precipitation with coenzyme Q10 (coQ10) was investigated in a two-step process. In step one, the effects of feed solution concentration, flow rates and flow rate ratios on the PGX-processed GA were studied. Low flow rates and high ratios resulted in larger (up to 65 m(2)/g) surface areas. In the second step, the impact of different recirculation flow rates and pressurization rates on the coQ10 loading was tested. Only an increased pressurization rate (4.5 vs. 1.5 MPa/min) showed an effect, increasing the coQ10 loading from 0.6 to 2.0% wow. PGX drying followed by adsorptive precipitation shows great potential for the development of bioactive delivery systems. (C) 2019 Elsevier B.V. All rights reserved.

Cellulose nanocrystal (CNC)-based aerogels are often produced through cryo-templating, followed by either critical point drying or freeze drying. While cryo-templating gives aerogels with a bimodal pore size distribution, better morphological control may be needed for certain applications. This work compares CNC aerogels prepared using a new processing method, called pressurized gas expansion (PGX) technology, to aerogels produced via cryo-templating. In all cases, CNCs were surface-modified with orthogonal functional groups to produce covalently cross-linked aerogels which are flexible and do not disperse in water. The aerogels were imaged by scanning electron microscopy and X-ray micro-computed tomography and further characterized by nitrogen sorption isotherms, X-ray diffraction, X-ray photoelectron spectroscopy, and compression testing. PGX aerogels appeared expanded and fibrillar at high magnification, with small mesopores and macropores less than 7 µm, but with large mound-like porous aggregates. Conversely, cryo-templated aerogels were comprised of denser CNC sheets surrounding macropores of 10–950 μm. Overall, PGX aerogels had a lower density, higher porosity, and a higher specific surface area than cryo-templated aerogels; they were also less stiff due to their morphology and reduced number of chemical cross-links. Scale-up of aerogel processing and understanding of the tunability of such methods may extend the use of CNCs in applications including insulation, separations, flexible supports, drug delivery, and template materials.

The recently developed Pressurized Gas eXpanded (PGX) liquid technology allows drying of high molecular weight water-soluble biopolymers, resulting in nano/micro-sized powders. The objective of this study was to investigate the adsorptive precipitation of co-enzyme Q10 (coQ10), a natural antioxidant, on PGX-processed beta-glucan, an oat-derived biopolymer. CoQ10 is first solubilized in supercritical CO2, which then carries it to the PGX-processed beta-glucan, resulting in the adsorptive precipitation. Different parameters, including the mode of operation (separate vs. simultaneous saturation and precipitation cycles), CO2 flow rate (70-465 mL/min), time of operation (15-90 min) and depressurization rate (0.5-13.0 MPa/min) were tested. Maximum coQ10 loading (18% w/w) was obtained after 45 min of operation at 40 degrees C, 30.0 MPa and 190 mL/min of CO2 flow rate, followed by a depressurization rate of 13.0 MPa/min. The two-step PGX process shows great potential for the preparation of bioactive-biopolymer delivery systems.

Coenzyme Q10 (coQ10) is a lipid-soluble antioxidant naturally present in all human cells, which plays a fundamental role during aerobic cellular respiration. The objective of this study was to investigate the solubility of coQ10 in supercritical carbon dioxide (SC-CO2) using a dynamic semi-continuous process at different conditions of pressure (10.0 to 30.0 MPa), temperature (32 degrees C to 50 degrees C) and addition of co-solvent (ethanol at 5 and 10 mol %) for potential scale up. Melting point depression of coQ10 in SC-CO2 decreased from 51.3 degrees C at ambient pressure to 32.6 degrees C after saturation with CO2 at 8.0 MPa. As expected, coQ10 solubility in SC-CO2 increased with CO2 density, from 6.5 x 10(-6) g/g(CO2) at 628.61 kg/m(3) to 3.4 x 10(-3) g/g(CO2) at 909.89 kg/m(3). The addition of 10 mol% of ethanol increased the solubility up to 7.8 x 10(-3) g/g(CO2). Better understanding of the coQ10 solubility behavior in SC-CO2 presents potential for developing novel processes for the production of ingredients for functional foods and natural health products.

The physicochemical properties of the oat beta-glucan powder (BG) and coenzyme Q10 (CoQ10)-loaded BG powder (L-BG) produced by the pressurized gas-expanded liquid (PGX) technology were studied. Helium ion microscope, differential scanning calorimeter, X-ray diffractometer, AutoSorb iQ and rheometer were used to determine the particle morphology, thermal properties, crystallinity, surface area and viscosity, respectively. Both BG (7.7μm) and L-BG (6.1μm) were produced as micrometer-scale particles, while CoQ10 nanoparticles (92nm) were adsorbed on the porous structure of L-BG. CoQ10 was successfully loaded onto BG using the PGX process via adsorptive precipitation mainly in its amorphous form. Viscosity of BG and L-BG solutions (0.15%, 0.2%, 0.3% w/v) displayed Newtonian behavior with increasing shear rate but decreased with temperature. Detailed characterization of the physicochemical properties of combination ingredients like L-BG will lead to the development of novel functional food and natural health product applications.

The industrial production of free fatty acids (FFA) by oil hydrolysis could benefit from the properties of supercritical carbon dioxide (SC-CO2). Indeed, SC-CO2 is an excellent reaction medium and its use simplifies the separation of the FFA from the product mixture. Although the benefits of SC-CO2 are known, it is not currently used commercially, in part due to the lack of reaction kinetics information. Therefore, the objective of this study was to investigate the kinetics of canola oil hydrolysis in SC-CO2 media. Reactions in SC-CO2 were conducted at 250°C, 10–30MPa, and using 1:3, 1:17 and 1:70 canola oil to water initial molar ratio (o/w). Reactions were also conducted in supercritical nitrogen at 10MPa, 250°C and 1:17 o/w. Samples were collected as a function of time and monoacylglycerol, diacylglycerol, triacylglycerol and FFA concentrations were determined. Rate constants were obtained by kinetic modeling of the data. The maximum rate of FFA production (FFAmax) was not affected (p>0.05) by supercritical media or pressure but it was delayed at 30MPa. FFAmax increased significantly (p<0.05) as the amount of water was increased from 1:3 to 1:17 and 1:70 o/w. Using the calculated rate constants, the mechanism of the hydrolysis of canola oil was determined. The findings provide valuable information for optimization of industrial hydrolysis.

Esterification of free fatty acids (FFA) with glycerol in supercritical carbon dioxide (SC-CO2) media to produce designer monoacylglycerols (MAG) for food, cosmetic, and pharmaceutical industries, was conducted to elucidate the reaction kinetics and provide the reaction mechanism. Reactions were conducted in SC-CO2 at 10–30MPa, 170–250°C in a batch stirred reactor using an anhydrous glycerol to oleic acid initial molar ratio (gly/oleic) of 10:1, 1:1 and 1:2 and in supercritical nitrogen at 10MPa and 250°C using 10:1 gly/oleic. Samples were collected as a function of time and MAG, diacylglycerol, triacylglycerol and FFA concentrations were determined using thin layer chromatography–flame ionization detection. The rate of MAG formation at 50% of equilibrium concentrations (Rate-50%) increased significantly (p≤0.05) with temperature but was not affected by pressure or supercritical media (p>0.05). Rate-50% values for 10:1 and 1:1 gly/oleic were similar (p>0.05) but higher (p≤0.05) than that for 1:2 gly/oleic. Equilibrium concentration of MAG significantly (p≤0.05) decreased with decreased initial glycerol concentration. The calculated rate constants provided a better understanding of the mechanism and are essential for optimal process design.

Glycerolysis–hydrolysis reactions to produce monoacylglycerol (MAG) and diacylglycerol (DAG) used in the production of functional foods and nutraceuticals were conducted in supercritical carbon dioxide (SC-CO2) media to elucidate the reaction kinetics, provide the reaction mechanism and assess the potential catalytic agent involved. Reactions were conducted in an electrically heated, magnetically stirred autoclave at 250°C, 10–30MPa, anhydrous glycerol/canola oil molar ratio of 34:1 and initial water content of 0 to 8% (w/w). Reactions were also conducted in supercritical nitrogen at 250°C, 10MPa, and 8% (w/w) initial water. Samples were collected as a function of time and the concentrations of MAG, DAG, free fatty acids (FFA) and triacylglycerol (TAG) were obtained using thin layer chromatography–flame ionization detection. The maximum rate of MAG formation at 20MPa was significantly higher (p≤0.05) than that at 30MPa, but similar (p>0.05) to that at 10MPa; a finding that has economical impact because a pressure of 10MPa can be reached without the use of a high-pressure pump. Rates of MAG formation in SC-CO2 and -N2 media were similar (p>0.05) thereby demonstrating that SC-CO2 does not contribute to catalysis. The maximum rate of MAG production at 10MPa was significantly higher (p≤0.001) for reaction with 4% (w/w) initial water compared with anhydrous reactions and was significantly lower (p≤0.05) compared to that of reaction with 8% (w/w) initial water. Although this study was unable to identify the catalytic reagent, it did show that water played an important role. Reactions were carried out up to 14h and equilibrium was reached at 9h. The average equilibrium composition (mol%) obtained at 9–10h for the reactions conducted at 10–30MPa with 4–8% (w/w) water was 66–71% MAG, 13–15% DAG, 13–17% FFA and 0–1% TAG. A MAG concentration of >65% is higher than that obtained in conventional glycerolysis where the concentration of MAG generally does not exceed 58%. Such findings not only demonstrate improved yields but also lead to a better understanding of the complex mechanisms of simultaneous glycerolysis–hydrolysis reactions and are critical for optimal process design targeting the MAG and DAG products.

Production of MAG by glycerolysis is important for food, pharmaceutical, and cosmetic industries. Conducting glycerolysis in supercritical carbon dioxide (SC-CO2) media has advantages over conventional alkali-catalyzed glycerolysis. However, kinetic data are lacking for such conversions in the presence of SC-CO2. The objectives of this study were to estimate the rate constants and elucidate the mechanism for the glycerolysis of soybean oil in SC-CO2 using previously reported data. The data were taken from experiments using soybean oil, glycerol (glycerol/oil molar ratios of 15–25) and water (3–8% w/w) in SC-CO2 at 20.7–62.1 MPa and 250°C for a 4 h period. Rate constants for the parallel glycerolysis and hydrolysis reactions were estimated for each processing parameter (glycerol/oil, water content, pressure) by minimizing the summed squared error between the values calculated from the experimental data and those obtained from the kinetic model. The results suggested that water and pressure had an effect on rate constants but the glycerol/oil ratio did not. Findings provide the kinetic modeling data necessary for the optimization of supercritical processes involving glycerolysis reactions for the production of MAG from vegetable oils.