RESUMEN

Bead foaming technique is regarded as a highly promising method for preparing foams with complex geometries and high expansion ratios. The biodegradability of poly(butylene adipate-co-terephthalate) (PBAT) has garnered significant attention in the field of foam materials. However, due to inherent disadvantages such as low melt strength and low modulus, PBAT faces challenges during bead foaming. In this study, a small amount of polylactic acid (PLA) was incorporated into PBAT. Utilizing the differential melting points of PLA and PBAT, PLA served as physical cross-linking points. The epoxy-based chain extender ADR4370S was used as a chain extender and compatibilizer. By varying its content, the compatibility and foaming performance of the PBAT/PLA blend were regulated. Finally, the foaming process employed supercritical carbon dioxide (scCO2) impregnation followed by heating to address the hydrolysis issue of the PBAT/PLA blend during bead foaming. The results demonstrated that the introduction of ADR could initiate reactions between its epoxy groups and PBAT and PLA, resulting in grafting and chain extension. When the ADR content reached 0.6 wt%, the cell structure evolved from a bimodal to a uniform cell structure, with a minimum average cell size of 12.3 µm and a maximum foaming ratio of 10.3 times.

RESUMEN

Supercritical carbon dioxide (SCCO2) is a non-toxic and environmentally friendly fluid and has been used in polymerization reactions, processing, foaming, and plasticizing of polymers. Exploring the behavior and data of SCCO2 sorption and dissolution in polymers provides essential information for polymer applications. This study investigated the sorption and diffusion of SCCO2 into polyetherimide (PEI). The sorption and desorption processes of SCCO2 in PEI samples were measured in the temperature range from 40 to 60 °C, the pressure range from 20 to 40 MPa, and the sorption time from 0.25 to 52 h. This study used the ex situ gravimetric method under different operating conditions and applied the Fickian diffusion model to determine the mass diffusivity of SCCO2 during sorption and desorption processes into and out of PEI. The equilibrium mass gain fraction of SCCO2 into PEI was reported from 9.0 wt% (at 60 °C and 20 MPa) to 12.8 wt% (at 40 °C and 40 MPa). The sorption amount increased with the increasing SCCO2 pressure and decreased with the increasing SCCO2 temperature. This study showed the crossover phenomenon of equilibrium mass gain fraction isotherms with respect to SCCO2 density. Changes in the sorption mechanism in PEI were observed when the SCCO2 density was at approximately 840 kg/m3. This study qualitatively performed FTIR analysis during the SCCO2 desorption process. A CO2 antisymmetric stretching mode was observed near a wavenumber of 2340 cm-1. A comparison of loss modulus measurements of pure and SCCO2-treated PEI specimens showed the shifting of loss maxima. This result showed that the plasticization of PEI was achieved through the sorption process of SCCO2.

RESUMEN

The pretreatment and saccharification of dewaxed bagasse (DWB) has been investigated under various reaction conditions ranging 2000 to 3200 psi, at 70 ± 1 °C in supercritical carbon dioxide (SCC). This has been in attempt to transform the DWB into fermentable sugar and bioethanol in high yields. The effect of SCC mediated pretreatment and enzymatic hydrolysis on structural and morphological alterations in DWB has been ascertained through diverse analytical methods. The sugar has been released through cellulase (40 FPU/mL) mediated enzymatic hydrolysis of pretreated DWB in sodium acetate buffer (pH 4.7) within 1 h at SCC 2800 psi, 70 ± 1 °C. The released sugar was subsequently fermented in the presence of yeast (Saccharomyces crevices, 135 CFU) at 28 ± 1 °C over 72 h to afford the bioethanol. The SCC mediated process conducted in acetic acid:water media (1:1) at 2800 psi, 70 ± 1 °C over 6 h has afforded the pretreated DWB with maximum yield towards the production of fermentable sugar and bioethanol. The production of fermentable sugar and bioethanol has been electrochemically estimated through cyclic voltammetry (CV) and square wave voltammetry (SWV) over glassy carbon electrode in KOH (0.1 M). The electrochemical methods were found selective and in close agreement for estimation of the yields (%) of fermentable sugars and bioethanol. The yield (%) of fermentable sugar estimated from CV and SWV were 80.10 ± 5.34 and 79.00 ± 5.09 respectively. Whereas the yield (%) of bioethanol estimated from CV and SWV were 81.30 ± 2.78% and 78.6 ± 1.25% respectively. Present investigation delivers a SCC mediated green and sustainable method of pretreatment of DWB to afford the enhanced saccharification, to produce bioethanol in high yields.

Asunto(s)

Biocombustibles , Dióxido de Carbono , Celulosa , Etanol , Fermentación , Etanol/metabolismo , Etanol/química , Celulosa/metabolismo , Celulosa/química , Dióxido de Carbono/metabolismo , Dióxido de Carbono/química , Hidrólisis , Saccharomyces cerevisiae/metabolismo , Celulasa/metabolismo

RESUMEN

This study explores the potential of Cucumaria frondosa (C. frondosa) viscera as a natural source of omega-3 FAs using supercritical carbon dioxide (scCO2) extraction. The extraction conditions were optimized using a response surface design, and the optimal parameters were identified as 75 °C and 45 MPa, with a 20 min static and a 30 min dynamic extraction, and a 2:1 ethanol to feedstock mass ratio. Under these conditions, the scCO2 extraction yielded higher FAs than the solvent-based Bligh and Dyer method. The comparative analysis demonstrated that scCO2 extraction (16.30 g of FAs/100 g of dried samples) yielded more fatty acids than the conventional Bligh and Dyer method (9.02 g, or 13.59 g of FAs/100 g of dried samples with ultrasonic assistance), indicating that scCO2 extraction is a viable, green alternative to traditional solvent-based techniques for recovering fatty acids. The pre-treatment effects, including drying methods and ethanol-soaking, were investigated. Freeze-drying significantly enhanced FA yields to almost 100% recovery, while ethanol-soaked viscera tripled the FA yields compared to fresh samples, achieving similar EPA and DHA levels to hot-air-dried samples. These findings highlight the potential of sea cucumber viscera as an efficient source of omega-3 FA extraction and offer an alternative to traditional extraction procedures.

Asunto(s)

Dióxido de Carbono , Ácidos Grasos Omega-3 , Vísceras , Animales , Dióxido de Carbono/química , Ácidos Grasos Omega-3/aislamiento & purificación , Ácidos Grasos Omega-3/química , Vísceras/química , Cromatografía con Fluido Supercrítico/métodos , Cucumaria/química , Pepinos de Mar/química , Liofilización

RESUMEN

The pharmaceutical industry is increasingly drawn to the research of innovative drug delivery systems through the use of supercritical CO2 (scCO2)-based techniques. Measuring the solubility of drugs in scCO2 at varying conditions is a crucial parameter in this context. In this research, the supercritical solubility of two pharmaceutical ingredients, namely Febuxostat and Chlorpromazine, has been assessed theoretically using various thermodynamic approaches, including PR, SRK, UNIQUAC, and Wilson models. Additionally, hybrid machine learning models of PO-GPR, and PO-KNN were applied to anticipate the supercritical solubility of these medicines. Verification of the accuracy of each model for each pharmaceutical substance is conducted against previously reported experimental solubility data. In the comparison between the SRK and PR models, it is observed that the SRK model displays greater precision in correlating the solubility of both drugs. It consistently achieves a mean Radj value of 0.995 across all cases and mean AARD% values of 14.47 and 9.30 for Febuxostat and Chlorpromazine, respectively. Furthermore, the findings indicate that the UNIQUAC model surpasses the Wilson model in precisely representing the solubility of both medicines. It consistently achieves a mean Radj value higher than 0.985 across both cases and mean AARD% values of 11.39 and 7.08 for Febuxostat and Chlorpromazine, respectively. Additionally, the performance of both hybrid machine learning models proved to be excellent in anticipating the supercritical solubility of both compounds.

Asunto(s)

Clorpromazina , Aprendizaje Automático , Solubilidad , Solventes , Termodinámica , Clorpromazina/química , Solventes/química , Febuxostat/química , Dióxido de Carbono/química , Química Farmacéutica/métodos , Modelos Químicos

RESUMEN

Hot air, water, and glycerol were studied as foaming mediums for the production of ETPU to evaluate their influence on the behavior of the foam and compare the optimal particles for each of the foaming temperatures selected. The results showed that the times of water foaming and glycerol foaming were shorter by about 2/3 than with hot-air foaming. The best foaming temperatures for hot-air foaming, glycerol foaming, and water foaming are 110-115 °C, 75 °C, and 90 °C, respectively. The particles of glycerol foam have a matte appearance and their gloss is not very good. However, the particles in hot-air foaming are light, and the gloss is very satisfactory. The gloss of the surface of water-foaming particles is dim. At the same time, there is a faint matte appearance. Particles made with glycerol foaming and water foaming are more even than those made with hot-air foaming. The density of foaming materials from glycerol foaming, hot-air foaming, and water foaming are raised accordingly, while the hardness of foaming materials from glycerol foaming, water foaming, and hot-air foaming are successively increased.

RESUMEN

In recent years, the supercritical CO2 extraction method has gained attention due to its use of environmentally friendly, non-toxic solvents, ability to operate at lower temperatures that do not cause the degradation of bioactive compounds, and capacity for rapid extraction. This method is particularly notable for isolating bioactive compounds from plants. The extracts obtained have shown superior properties due to their activity against diseases such as cancer, which is one of the leading causes of death worldwide. The aim of this study is to provide an in-depth understanding of the supercritical CO2 extraction method, as well as to discuss its advantages and disadvantages. Furthermore, the study includes specific data on various plant materials, detailing the following parameters: plant name and region, bioactive compounds or compound classes, extraction temperature (°C), pressure (bar), time (minutes), co-solvent used, and flow rate. Additionally, this study covers extensive research on the isolation of bioactive compounds and the efficacy of the obtained extracts against cancer.

RESUMEN

Keratitis is a corneal infection caused by various bacteria and fungi. Eye drop treatment of keratitis involves significant challenges due to difficulties in administration, inefficiencies in therapeutic dosage, and frequency of drug applications. All these are troublesome and result in unsuccessful treatment, high cost, time loss, development of drug resistance by microorganisms, and a massive burden on human health and the healthcare system. Most of the antibacterial and antifungal medications are non-water-soluble and/or include toxic drug formulations. Here, the aim was to develop drug-loaded contact lenses with therapeutic dosage formulations and extended drug release capability as an alternative to eye drops, by employing supercritical carbon dioxide (ScCO2) as a drug impregnation solvent to overcome inefficient ophthalmic drug use. ScCO2, known as a green solvent, has very low viscosity which provides high mass transfer power and could enhance drug penetration into contact lenses much better with respect to drug loading using other solvents. Here, moxifloxacin (MOX) antibiotic and amphotericin B (AMB) antifungal medicines were separately loaded into commercially available silicone hydrogel contact lenses through 1) drug adsorption from the aqueous solutions and 2) impregnation techniques via ScCO2 and their efficacies were compared. Drug impregnation parameters, i.e., 8-25 MPa pressure, 310-320 K temperature, 2-16-hour impregnation times, and the presence of ethanol as polar co-solvent were investigated for the optimization of the ScCO2 drug impregnation process. The highest drug loading and long-term release kinetic from the contact lenses were obtained at 25 MPa and 313 K with 2.5 h impregnation time by using 1 % ethanol (by volume). Furthermore, antibacterial/antifungal activities of the MOX- and AMB-impregnated contact lenses were effective against in vitro Pseudomonas aeruginosa (ATCC 10145) bacteria and Fusarium solani (ATCC 36031) fungus for up to one week. Consequently, the ScCO2 method can be effectively used to impregnate commercial contact lenses with drugs, and these can then be safely used for the treatment of keratitis. This offers a sustainable delivery system at effective dosage formulations with complete bacterial/fungal inhibition and termination, making it viable for real animal/human applications.

Asunto(s)

Anfotericina B , Antibacterianos , Antifúngicos , Dióxido de Carbono , Queratitis , Moxifloxacino , Dióxido de Carbono/química , Queratitis/tratamiento farmacológico , Queratitis/microbiología , Antibacterianos/química , Antibacterianos/administración & dosificación , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/administración & dosificación , Moxifloxacino/administración & dosificación , Moxifloxacino/química , Moxifloxacino/farmacología , Anfotericina B/administración & dosificación , Anfotericina B/química , Anfotericina B/farmacología , Liberación de Fármacos , Lentes de Contacto/microbiología , Fusarium/efectos de los fármacos , Humanos , Hidrogeles/química , Sistemas de Liberación de Medicamentos , Solventes/química , Infecciones Fúngicas del Ojo/tratamiento farmacológico , Infecciones Fúngicas del Ojo/microbiología

RESUMEN

Carbon nanotube (CNT) fibers are renowned for their exceptional axial tensile strength and modulus. However, in yarn form, they frequently encounter transverse loading in practical applications, which exposes their suboptimal mechanical attributes rooted in inadequate inter-tube interactions and yarn surface defects. Efforts to mitigate micro-slippage among CNTs have encompassed gap-filling methodologies with varied materials, yet the outcomes have fallen short of expectations. This work aimed to enhance the mechanical properties of CNT yarns via infiltration with polyacrylonitrile (PAN) under supercritical carbon dioxide (sc-CO2) conditions. PAN was strategically chosen for its capability to undergo pre-oxidation and subsequent carbonization, leading to robust graphitic reinforcement. Leveraging sc-CO2's swelling and high permeability properties, the infiltration process effectively plugged interstitial spaces, elevating the yarn's tensile strength to 277.50 MPa and Young's modulus to 5094.05 MPa. Additional enhancements were realized after pre-oxidation, conferring a dense, reinforced shell structure that augmented tensile strength by 96.93% and Young's modulus by 298.80%. Scanning electron microscopy (SEM) analyses revealed a homogeneous PAN distribution within the yarn matrix, corroborated by X-ray photoelectron spectroscopy (XPS) evidence of C-N bonding, indicative of a successfully interlaced network. Consequently, this investigation introduces a novel strategy to tackle micro-slippage in CNT yarns, thereby achieving substantial improvements in their mechanical resilience.

RESUMEN

In this study, a twin-screw extruder was used to fabricate poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends and blend-based nanocomposites with carbon nanotube (CNT) or nanocarbon black (CB) as nanofillers. The fabricated samples were subsequently treated with supercritical carbon dioxide (scCO2) to fabricate the corresponding foams. Bi-phasic morphology and selective distribution of CNTs or CBs in the PBAT phase were observed in the blends/composites through scanning electron microscopy. After the scCO2 treatment, the selective foaming of the PBAT phase in the prepared blends/composites was confirmed. The cellular structure of PBAT phase in scCO2-treated blends is similar to the size/shape of PBAT domains in untreated blends or treated neat PBAT foam. The addition of CNTs or CBs in the blends led to a slight reduction in cell size of the foamed PBAT phase, demonstrating CNT/CB-induced cell nucleation. Differential scanning calorimetry (DSC) results showed that CNTs and CBs played as nucleating agents and increased the initial crystallization temperature up to 14 °C compared with neat PBAT for PBAT in different composites during cooling. The scCO2 treatment induced the bimodal stability of PBAT crystals in different samples, which melted mainly in two temperature regions in DSC studies. Thermogravimetric analyses revealed that compared with parent blends, the addition of CNTs or CBs increased the temperature at 80 wt.% loss (degradation of PBAT portion) up to 6 °C. The electrical resistivity decreased by more than six orders of magnitude for certain CNT- or CB-added composites compared with the parent blends. The hardness of the blends slightly increased after forming the corresponding composites and then declined after the scCO2 treatment.

RESUMEN

The aim of this research was to investigate the effects of supercritical carbon dioxide (SC-CO2) treatment on protein structure in Mongolian cheese. The peptides during the digestive process of the SC-CO2 treated cheese were also studied. SC-CO2 technology was utilized to treat Mongolian cheese at three temperatures (45, 55 and 65 °C) and three pressures (7.5, 12.5 and 17.5 MPa). The results of fluorescence, ultraviolet-visible, Fourier transform infrared spectroscopy and free sulfhydryl groups showed that SC-CO2, particularly at 65 °C and 17.5 MPa, modified the protein structure in Mongolian cheese effectively. The data of LC-MS/MS-based peptidomics showed that the content of antimicrobial peptides found in the SC-CO2 treated Mongolian cheese was 1.55 times that of the untreated Mongolian cheese; the content of unique antimicrobial peptides in the digested SC-CO2 treated Mongolian cheese was 1.46 times that of the digested untreated Mongolian cheese, which proved that SC-CO2 could help produce antimicrobial peptides in cheese not only during the process of SC-CO2 treatment but during subsequent simulated gastrointestinal digestion as well. In conclusion, SC-CO2 could be considered a promising method to develop cheese products with potential health benefits.

Asunto(s)

Péptidos Antimicrobianos , Dióxido de Carbono , Queso , Digestión , Queso/análisis , Dióxido de Carbono/química , Péptidos Antimicrobianos/química , Manipulación de Alimentos/métodos , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría de Masas en Tándem , Presión , Temperatura

RESUMEN

This study's main objectives are to evaluate and confirm the effects of the extraction process, operating conditions, solvent type and solvent polarity on the yield and quality of the extracts. Supercritical carbon dioxide (scCO2) and Soxhlet were specially used in this study to extract bioactive chemicals from the seeds of a natural plant known as Plantago ovata. No studies have been published so far regarding the extraction from the seeds of this plant using scCO2.The effects of three operating parameters (pressure, temperature and particle size) on the extraction yield, total phenolic content, total flavonoid content (TFC), total tannin content (TTC) and antioxidant activity were assessed in this study using the Box-Behnken statistical experimental design (BBD). The chemical components in the extracts were separated and identified using gas chromatography mass spectrometry. According to the antioxidant activity results, scCO2 failed to produce bioactive compounds with interesting properties when operated within operating range conditions.

RESUMEN

The emerging nutraceutical, fucoxanthin, shows promise as a high-value product to enable the integrated biorefinery. Fucoxanthin can be extracted from algae through supercritical fluid extraction (SFE), but literature does not agree on optimal extraction conditions. Here, a statistical analysis of literature identifies supercritical carbon dioxide (scCO2) density, ethanol cosolvent amount, and polarity as significant predictors of fucoxanthin yield. Novel SFE experiments are then performed using a fucoxanthin standard, describing its fundamental solubility. These experiments establish solvent system polarity as the key knob to tune fucoxanthin recovery from 0% to 100% and give specific operating conditions for targeted fucoxanthin extraction.Further experiments compare extractions on fucoxanthin standard with extractions from Phaeodactylum tricornutum microalgae to elucidate the effect of the algae matrix. Results show selectivity of fucoxanthin over chlorophyll in scCO2 microalgae extractions that was not seen in extractions with ethanol, indicating a benefit of scCO2 to design selective extraction schemes.

Asunto(s)

Cromatografía con Fluido Supercrítico , Microalgas , Xantófilas , Cromatografía con Fluido Supercrítico/métodos , Xantófilas/aislamiento & purificación , Xantófilas/química , Microalgas/química , Etanol/química , Dióxido de Carbono/química , Solventes/química , Diatomeas/química , Clorofila , Biotecnología/métodos

RESUMEN

Waterless dyeing of polyamide 6.6 using scCO2 (supercritical carbon dioxide) was investigated. PA (polyamide) fibers can be dyed with various dyes, including disperse dyes. The conventional aqueous dyeing process uses large amounts of water and produces polluted water. Considering these environmental issues, waterless dyeing of fibers is a forefront issue, and utilization of supercritical carbon dioxide (scCO2) is a commercially viable technology for waterless dyeing. This study tested PA6.6 (polyamide 6.6) dyeing in scCO2 at 100 °C 220 bar pressure for 45 min. Color measurements and color fastness tests were performed, as well as tensile strength, scanning electron microscope (SEM) analysis, and Fourier transform infrared spectroscopy (FTIR) analysis. PA6.6 fabrics yielded higher K/S (color strength, the Kubelka-Munk equation) values with larger molecular weight dye and almost the same color strength with medium and small-sized dyes, demonstrating the ability of dyeing in a supercritical environment without water as a more environmentally friendly dyeing option compared to conventional dyeing.

RESUMEN

Chitin is a structural polysaccharide abundant in the biosphere. Chitin possesses a highly ordered crystalline structure that makes its processing a challenge. In this study, chitin hydrogels and methanogels, prepared by dissolution in calcium chloride/methanol, were subjected to supercritical carbon dioxide (scCO2) to produce porous materials for use as scaffolds for osteoblasts. The control of the morphology, porosity, and physicochemical properties of the produced materials was performed according to the operational conditions, as well as the co-solvent addition. The dissolution of CO2 in methanol co-solvent improved the sorption of the compressed fluid into the hydrogel, rendering highly porous chitin scaffolds. The chitin crystallinity index significantly decreased after processing the hydrogel in supercritical conditions, with a significant effect on its swelling capacity. The use of scCO2 with methanol co-solvent resulted in chitin scaffolds with characteristics adequate to the adhesion and proliferation of osteoblasts.

RESUMEN

In order to reduce the environmental impact of poly(ethylene terephthalate) (PET) plastic waste, supercritical fluids were used to facilitate effective recovery via improved solvent effects. This work focuses on the mechanisms of supercritical CO2 (ScCO2) during the alcoholysis processing of PET using systematic experiments and molecular dynamics (MD) simulations. The results of the alcoholysis experiment indicated that PET chips can be completely depolymerized within only an hour at 473 K assisted with ScCO2 at an optimal molar ratio of CO2/ethanol of 0.2. Random scission of PET dominates the early stage of the depolymerization reaction process, while specific scission dominates the following stage. Correspondingly, molecular dynamics (MD) simulations revealed that the solubilization and self-diffusion properties of ScCO2 facilitate the transportation of alcohol molecules into the bulk phase of PET, which leads to an accelerated diffusion of both oligomers and small molecules in the system. However, the presence of excessive CO2 has a negative impact on depolymerization by weakening the hydrogen bonding between polyester chain segments and ethanol, as well as decreasing the swelling degree of PET. These data provide a deep understanding of PET degradation by alcohols and the enhancement of ScCO2. It should be expected to achieve an efficient and high-yield depolymerization process of wasted polyesters assisted with ScCO2 at a relatively low temperature.

RESUMEN

This study investigated the in vitro digestibility of starch and protein aerogels produced from defatted rice bran (DRB), an underutilized rice processing byproduct, using supercritical carbon dioxide (SC-CO2) drying. The extracted starch (i.e., purified starch), crude starch, and proteins were used for the aerogel formation at 15% (w/w) concentration and further characterized. All aerogels exhibited three-dimensional open porous structures with high surface areas of 36-47 m2/g, densities lower than 0.3 g/cm3, and porosities higher than 84%. The starch hydrolyses in starch and crude starch aerogels were 86 and 73%, respectively, while the protein hydrolysis in protein aerogels reached up to 82% after sequential oral, gastric, and intestinal digestion. Thus, the hydrolysis rates achieved in simulated digestions suggest that the developed aerogels from DRB have the potential to serve as vehicles for delivering bioactive compounds and add value to the underutilized DRB.

Asunto(s)

Dióxido de Carbono , Digestión , Geles , Oryza , Proteínas de Plantas , Almidón , Oryza/química , Oryza/metabolismo , Almidón/química , Almidón/metabolismo , Dióxido de Carbono/química , Geles/química , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Modelos Biológicos , Hidrólisis , Humanos , Desecación/métodos

RESUMEN

Supercritical CO2 has wide application in enhancing oil recovery, but the low viscosity of liquid CO2 can lead to issues such as poor proppant-carrying ability and high filtration loss. Therefore, the addition of thickening agents to CO2 is vital. Hydrocarbon polymers, as a class of green and sustainable materials, hold tremendous potential for acting as thickeners in supercritical CO2 systems, and PVAc is one of the best-performing hydrocarbon thickeners. To further improve the viscosity enhancement and solubility of PVAc, here we designed a novel polymer structure, PVAO, by introducing CO2-affine functional groups to PVAc. Molecular dynamics simulations were adopted to analyze viscosity and relevant solubility parameters systematically. We found that PVAO exhibits superior performance, with a viscosity enhancement of 1.5 times that of PVAc in supercritical CO2. While in the meantime, PVAO maintains better solubility characteristics than PVAc. Our findings offer insights for the future design of other high-performance polymers.

RESUMEN

This study aims to use a static-based solubility method for measuring the solubility of lumiracoxib at a temperature of 308-338 K and pressure of 120-400 bar for the first time. The obtained solubility data for lumiracoxib is between 4.74 × 10-5 and 3.46 × 10-4 (mole fraction) for the studied ranges of pressure and temperature. The solubility values reveal that the lumiracoxib experiences a crossover pressure of about 160 bar. Moreover, the measured solubility data of these two drugs are correlated with density-based semi-empirical correlations namely Bartle et al., Mendez-Santiago-Teja, Kumar and Johnstone, Chrastil and modified Chrastil models with an average absolute relative deviation of 10.7%, 9.5%, 9.8%, 7.8%, and 8.7% respectively for lumiracoxib. According to these findings, it is obvious that all of the examined models are rather accurate and there is no superiority between these models for both examined drugs although the Chrastil model is slightly better in the overall view.

RESUMEN

An eco-friendly approach towards the recovery of value-added extracts from olive tree leaves with the aid of supercritical CO2 at 30 MPa was carried out. The impact of extraction temperature (35-90 °C) and presence of co-solvents (ethanol, water, and aqueous ethanol) on the total phenolic, flavonoid, and pigment content, as well as oleuropein, hydroxytyrosol, tyrosol, and α-tocopherol content was determined. In addition, the antioxidant activity of extracts from tree leaves using DPPH, ABTS, and CUPRAC assays was investigated. The results of the study showed that the most effective supercritical CO2 extraction was at 90 °C with an addition of ethanol, which enabled the separation of extract with the highest content of tested compounds. Some of the highest recorded values were for oleuropein 1.9 mg/g, for carotenoids 5.3 mg/g, and for α-tocopherol 2.0 mg/g. Our results are expected to contribute to the efforts towards the valorization of olive leaves as a sustainable source of valuable compounds, and boost local economies as well as the interest of pharmaceutical, food, and cosmetic industries for novel food by-product applications.