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Predloženo tehničko rešenje opisuje tehnološki postupak za dobijanje aerogelova skroba velike poroznosti. Ovim tehničkim rešenjem prevazilaze se ekološki problemistvaranja i akumulacije otpada. Aerogelovi su proizvedeni od biokompatibilnih materijalaiz obnovljivih izvora upotrebom zelenog medujuma (natkritičnog ugljen(IV)-oksida). Zeleni medijum se u potpunosti uklanja iz finalnog proizvoda i može da se reciklira nakon proizvodnje materijala.Predloženim tehnološkim postupkom proizvodnje omogućava se ušteda vremena i energije za proizvodnju polisaharidnih aerogelova koji imaju poroznost do 82%.Dobijeni aerogelovi se mogu upotrebiti u medicini za tretiranje vlažnih rana jer apsorbuju do 420% okolne tečnosti.Vlažne rane proizvode značajnu količinu eksudata ili tečnosti i njihov tretman je ključan za promovisanje pravilnog zarastanja i sprečavanje infekcija. Dodatno,usled biodegradabilnosti skroba korišćenjem proizvedenih aerogelova izbegava se akumulacija otpada nakon upotrebe istog.

Due to the high use and misuse of antibiotics over the years, microbes have developed resistance to a significant number of drugs (so-called antimicrobial resistance - AMR) [1]. Therefore, the necessity for the development of natural antimicrobial agents to overcome growing bacterial resistance against synthetic antibiotics has been recognized. Thymol is a natural monoterpenoid, with proven anti-inflammatory, antioxidant, and antimicrobial properties and it has been recognized as safe by the FDA (it has GRAS status). With the aim to fabricate material with antibacterial activity, supercritical solvent impregnation (SSI) was applied for loading of commercial PLA-based absorbable surgical sutures with thymol in a green medium, supercritical CO2. Operating temperature and pressure were set to 35 °C and 10 MPa, while contact time was varied between 1 and 6 h. The SSI process was performed under mild processing parameters to obtain an effective amount of loaded thymol against tested bacteria keeping in mind the recommended safe content of thymol for human blood cells (in terms of cytotoxicity and mutagen effect) [2]. Selected process conditions enabled thymol loadings of 3.9–5.6% (Fig. 1) [3]. SEM analyses was used to monitor sutures' morphological change from swelling to agglutination induced by the increased amount of thymol in the material. ...

The supercritical fluid extraction (SFE) technique that employs supercritical carbon dioxide (SC-CO2) has been reported to be superior (compared to mechanical and extractions with organic solvents) for the separation of oils from seeds [1]. Current work aims to show that besides oils, additional valuable extracts can be recovered from defatted seeds. For that purpose, seeds of milk thistle, dandelion and chamomile grown in Poland have been tested. Initially, SFE for oil separation from seeds was tested by variation in pressure (from 100 to 450 bar) and temperature (from 40 to 80 °C) [2–4]. The yield and composition of oils indicated optimal conditions for the separation of extracts from defatted seeds using SC-CO2 with ethanol. ...

Predloženo tehničko rešenje opisuje tehnološki postupak za dobijanje antimikrobnih aerogelova skroba. Bioaktivni materijala su proizvedeni primenom ekološki prihvatljivih tehnika upotrebom zelenog medujuma (natkritičnog ugljen(IV)-oksida), biokompatibilnih i biorazgradivih materijala iz obnovljivih izvora i prirodnih bioaktivnih jedinjenja. Zeleni medijum se u potpunosti uklanja iz finalnog proizvoda i može se reciklirati nakon proizvodnje. Proizvedeni aerogelovi skroba sa timolom, eugenolom, karvakrolom i citronelolom (12,815,8 mass%) pokazuju jaku antimikrobnu aktivnost. Dobijeni aerogelovi se mogu upotrebiti u medicini za tretiranje inficiranih rana jer apsorbuju do 265 do 569% okolne tečnosti i inhibiraju rast Gram-negativnih bakterija, Gram-pozitivnih bakterija i gljivica (veličina prečnika zone inhibicije je do 37,5 mm). Predmetno tehničko rešenje pokazuje obećavajući zeleni pristup za proizvodnju bioaktivnih dvokomponentnih materijala na bazi skroba za potencijalnu primenu u lečenju infekcija kože. Ovim rešenjem prevazilaze se ekološki problemi stvaranja otpada prilikom proizvodnje bioaktivnih materijala i korišćenjem proizvedenog materijala izbegava se akumulacija otpada nakon upotrebe.

Aerogels are materials with high specific surface area and high porosity, which can be produced from polysaccharides such as starch [1,2]. Starch is an abundant and low-cost polymer with versatility in processing. Aerogel properties are influenced by the process parameters including starch-to-water ratio, gelatinization temperature (T), selection of non-solvent for water replacement in hydrogels, selection of drying method, drying pressure (P) and T, etc. [1,2]. Supercritical drying, which employs supercritical carbon dioxide (scCO2), is an environmentally friendly process that allows relatively fast production of aerogels. Despite the superior properties of starch aerogels, they do not express biological activity. This can be overcome by the incorporation of bioactive compounds (BCs) into aerogels using the supercritical impregnation (SCI) process [3,4]. SCI implies the dissolution of BCs in scCO2, diffusion of BC-scCO2 solution into a polymer matrix, possible chemical or physical interaction of BC with polymer, and complete removal of scCO2 from the BC-polymer after a decrease of P and T to atmospheric. This process allows one-step production of solvent-free added value materials at relatively low T and the incorporation of high amounts of BC with various biological activities. Aerogels can be impregnated with pharmaceutical drugs but also with natural BCs (single or mixture) such as plant extracts [3,4]. To produce aerogels, 10 g of cornstarch (amylose content 20−30%, HeMoss, Serbia) was mixed with 100 mL of distilled water, gelatinization T was changed from 70 to 100 °C, water contained in hydrogels was replaced with acetone or ethanol during 1 or 5 days, drying P was varied from 8 to 20 MPa while drying T was 35 or 40 °C. Drying of gels was performed in a 25 mL high-pressure view cell while impregnation of aerogels with BCs was performed in a 280 mL high-pressure unit (Eurotechnica GmbH, Germany). Developed aerogels were tested as possible carriers of hemp and

Aerogels are materials with high specific surface area and high porosity, which can be produced from polysaccharides such as starch [1,2]. Starch is an abundant and low-cost polymer with versatility in processing. Aerogel properties are influenced by the process parameters including starch-to-water ratio, gelatinization temperature (T), selection of non-solvent for water replacement in hydrogels, selection of drying method, drying pressure (P) and T, etc. [1,2]. Supercritical drying, which employs supercritical carbon dioxide (scCO2), is an environmentally friendly process that allows relatively fast production of aerogels. Despite the superior properties of starch aerogels, they do not express biological activity. This can be overcome by the incorporation of bioactive compounds (BCs) into aerogels using the supercritical impregnation (SCI) process [3,4]. SCI implies the dissolution of BCs in scCO2, diffusion of BC-scCO2 solution into a polymer matrix, possible chemical or physical interaction of BC with polymer, and complete removal of scCO2 from the BC-polymer after a decrease of P and T to atmospheric. This process allows one-step production of solvent-free added value materials at relatively low T and the incorporation of high amounts of BC with various biological activities. Aerogels can be impregnated with pharmaceutical drugs but also with natural BCs (single or mixture) such as plant extracts [3,4]. To produce aerogels, 10 g of cornstarch (amylose content 20−30%, HeMoss, Serbia) was mixed with 100 mL of distilled water, gelatinization T was changed from 70 to 100 °C, water contained in hydrogels was replaced with acetone or ethanol during 1 or 5 days, drying P was varied from 8 to 20 MPa while drying T was 35 or 40 °C. Drying of gels was performed in a 25 mL high-pressure view cell while impregnation of aerogels with BCs was performed in a 280 mL high-pressure unit (Eurotechnica GmbH, Germany). Developed aerogels were tested as possible carriers of hemp and

The study aimed toward the development of biocompatible and biodegradable polymeric films (starch-chitosan and starch-chitosan-cyclodextrin) with biologically valuable green tea leaf extract using an environmentally friendly integrated process of supercritical fluid extraction (SFE) and supercritical solvent impregnation (SSI). The SFE-SSI process parameters were selected through the initial estimation of the SFE parameters effect (temperatures 35 and 70 °C and the addition of co-solvents ethanol, ethanol/water, and water). The present early-stage work showed that an increase in temperature increased extraction yield (from 0.9 to 4.2%) and caffeine content while it decreased polyphenolic and pigment content as well as antioxidant activity and extract loading onto films (from 7.1 to 0.1%). The addition of co-solvents to sc-CO2 had an adverse effect on extract yield, composition, and loading. The highest recorded total phenolic, flavonoid, chlorophyll A, and caffeine content in extracts were 136.5 mg GE/g, 22.7 mg RE/g, 8.1 mg/g, and 460.0 mg/g, respectively.

This study focuses on the development of bioactive materials using environmentally friendly techniques, renewable, biocompatible, and biodegradable polysaccharide, as well as natural bioactive compounds (NBCs) found in plant extracts. First, cornstarch aerogels with a porosity of 86 % and a specific surface area of 225 m2/g were produced via supercritical CO2- assisted drying. Further, thymol, citronellol, carvacrol, and eugenol were incorporated into the aerogels by supercritical CO2- assisted impregnation, which allowed variation in loadings of NBCs (12.8–17.6 %). Interaction between cornstarch aerogels and NBCs determined impregnation rate, pore wall thickness (in the range 18–95 nm), liquid absorption capacity (from 265 to 569 %), dehydration mass loss, and release in phosphate-buffered saline. Controlled release of NBCs was maintained over a 3-day period. Moreover, impregnated aerogels showed a significant antioxidant effect with the highest value for DPPH radical inhibition of 25.5 % determined for the aerogels impregnated with eugenol. Notable antimicrobial activity against tested Gram-negative bacteria, Gram-positive bacteria, and fungi was also observed, being the highest for thymol-loaded aerogel with the diameter of the inhibition zones of up to 37.5 mm. This work shows a promising green approach for the production of bioactive two-component starch-based materials for potential applications in skin infection treatment.

The study aimed toward the development of biocompatible and biodegradable polymeric films (starch-chitosan and starch-chitosan-cyclodextrin) with biologically valuable green tea leaf extract using an environmentally friendly integrated process of supercritical fluid extraction (SFE) and supercritical solvent impregnation (SSI). The SFE-SSI process parameters were selected through the initial estimation of the SFE parameters effect (temperatures 35 and 70 °C and the addition of co-solvents ethanol, ethanol/water, and water). The present early-stage work showed that an increase in temperature increased extraction yield (from 0.9 to 4.2%) and caffeine content while it decreased polyphenolic and pigment content as well as antioxidant activity and extract loading onto films (from 7.1 to 0.1%). The addition of co-solvents to sc-CO2 had an adverse effect on extract yield, composition, and loading. The highest recorded total phenolic, flavonoid, chlorophyll A, and caffeine content in extracts were 136.5 mg GE/g, 22.7 mg RE/g, 8.1 mg/g, and 460.0 mg/g, respectively.

The Polymer group of the Faculty of Technology and Metallurgy University of Belgrade deals with environment-sensitive hydrogel as carriersfor biomedical applications, including drug delivery, wound healing, and regenerative medicine. The first hydrogel generation synthesized in our labs was discs made of polyacrylamide and its derivatives. The synthesis was at higher temperatures (50 °C), with traditional crosslinker, N, N’-methylenebisacrylamide, and persulphate/pyrosulphate as initiator. Due to the growing demands for environmental sustainability, the general approach changed to reduce petrochemical raw materials and prepare eco-friendly materials focusing on 1) renewable polymers, initiators, and crosslinkers and 2) the application of simple, cost-effective, and eco-friendly approaches in hydrogel synthesis. To obtain the second hydrogel generation, we use renewable polymers: polysaccharides, proteins, and polyhydroxyalkanoates [1]. Still, the mechanical strength was weak. Hence, the applicationof carboxylic acids, methacrylic and itaconic, and N-isopropyl acrylamide improves mechanical properties and enhances the environmental stimuli of the carriers. Instead of traditional crosslinkers -organic molecules, we gave the advantage to plant extracts like genipin, sodium tripolyphosphate, citric acid, and calcium chloride. We made beads, microgels, aerogels, discs, films, and cylinders sensitive to pH, temperature, magnetic field, or specific molecules such as glucose. Facing an everyday challenge, improving drug delivery routes, especially for poorly water-soluble drugs, and finding an alternative to traditional antibiotics, encapsulation, and controlled release remain a challenge. Therefore, we used a mild condition (e.g., deep coating) to encapsulate/release traditional water-soluble and poorly water-soluble drugs, proteins, phenolic compounds, or supercritical carbon dioxide (scCO2) for thymol, carvacrol, and eugenol, a promising alternative for traditional antib

The Polymer group of the Faculty of Technology and Metallurgy University of Belgrade deals with environment-sensitive hydrogel as carriersfor biomedical applications, including drug delivery, wound healing, and regenerative medicine. The first hydrogel generation synthesized in our labs was discs made of polyacrylamide and its derivatives. The synthesis was at higher temperatures (50 °C), with traditional crosslinker, N, N’-methylenebisacrylamide, and persulphate/pyrosulphate as initiator. Due to the growing demands for environmental sustainability, the general approach changed to reduce petrochemical raw materials and prepare eco-friendly materials focusing on 1) renewable polymers, initiators, and crosslinkers and 2) the application of simple, cost-effective, and eco-friendly approaches in hydrogel synthesis. To obtain the second hydrogel generation, we use renewable polymers: polysaccharides, proteins, and polyhydroxyalkanoates [1]. Still, the mechanical strength was weak. Hence, the applicationof carboxylic acids, methacrylic and itaconic, and N-isopropyl acrylamide improves mechanical properties and enhances the environmental stimuli of the carriers. Instead of traditional crosslinkers -organic molecules, we gave the advantage to plant extracts like genipin, sodium tripolyphosphate, citric acid, and calcium chloride. We made beads, microgels, aerogels, discs, films, and cylinders sensitive to pH, temperature, magnetic field, or specific molecules such as glucose. Facing an everyday challenge, improving drug delivery routes, especially for poorly water-soluble drugs, and finding an alternative to traditional antibiotics, encapsulation, and controlled release remain a challenge. Therefore, we used a mild condition (e.g., deep coating) to encapsulate/release traditional water-soluble and poorly water-soluble drugs, proteins, phenolic compounds, or supercritical carbon dioxide (scCO2) for thymol, carvacrol, and eugenol, a promising alternative for traditional antib

Investigations of the process of supercritical fluid extraction (SFE) from dandelion were so far mainly focused on extractions from herb, leaves and root [1-3]. In the work presented here, the extraction process from seeds was investigated on a laboratory and semi-industrial scale equipment. The milled plant material with an average particle size of 0.41 ± 0.02 mm was used in all experiments. All SFEs were conducted with carbon-dioxide in supercritical state (SCCO2) as a solvent on pressure of 450 bar and temperature of 60°C, as these parameters were previously shown to be optimal for obtaining high-value extracts from dandelion seeds [4]. Experiments were conducted on laboratory (dia.=7.7 cm, vol=0.56 l, CO2 flow=11 kg/h) and semiindustrial (dia.=23.5 cm, vol.=397 l, CO2 flow=240 kg/h) scale equipment. On both scales several experiments were conducted with initial mass of the plant material (Ms) being the only variable parameter: laboratory scale Ms=26–104 g; semi-industrial scale Ms=2.2–8.8 kg. Fractions of extract were collected during the extractions in order to obtain data on the kinetics of the SFE processes. The results of the performed experiments are depicted in Figure 1. It can be seen that for both scales the rate of SFE, as well as the final yield, increases with increase of the mass of plant material, indicating that with the selected conditions, namely flowrate of CO2, the residence time was not long enough to allow saturation of the CO2 in the first part of the process, nor to enable extraction of all available extract. Similar trends on both scales can be perceived as a good basis for further investigations aiming at scale-up of the process of SFE from dandelion seeds. Experiments with larger packed bed height, which would enable higher residence times, should be conducted in order to achieve saturation at least in the first part of the SFE process. Mathematical models of the SFE process, supported by models for estimation of the kinetic parameters

Supercritical carbon dioxide (sc-CO2) has remarkable attributes as a processing medium such as high diffusivity, low viscosity, non-flammability, and inertness. In addition, it can be easily and completely separated from the final material, as well as fully recycled. This sets up sc-CO2-assisted technologies apart from conventional methodologies reliant on organic solvents. Some of the most prominent techniques that employ sc-CO2 are supercritical drying and supercritical impregnation for the functionalization of polymeric nanofibers, textiles, films, foams, and aerogels. Supercritical drying can be employed for the separation of liquids from wet polymer gels and the production of highly porous dry aerogels, while supercritical impregnation can be employed for the incorporation of bioactive components into polymer matrices. Overall, sc-CO2 technologies pioneer the development of next-generation materials while meticulous physical and chemical characterizations underpin the scientific journey.

The main aim of this study was to evaluate chamomile seeds as a new source of valuable bioactive compounds. For this purpose, a green extraction technique was employed with supercritical carbon dioxide (sc-CO2) as a solvent and ethanol as a co-solvent. The extracts from chamomile seeds with an average particle size of 0.20 mm were extracted at pressures of 30 and 45 MPa and temperatures of 40 and 60 °C. The composition of extracts was investigated by a gas chromatography-mass spectrometry analytical method as well as Folin−Ciocalteu assay (for total phenolic content) and total flavonoid content test. The antioxidant activity of obtained chamomile extracts was evaluated using DPPH radical. The antimicrobial effect of extracts was tested on yeasts, Gram-positive, and Gram-negative bacteria while the cytotoxic effect was evaluated on normal and cancer cells. The extraction process parameters were evaluated and results showed a significant effect of operating pressure, temperature, and the addition of co-solvent on the amount of separated chamomile extract and its composition. The extraction yield ranged from 2.1 to 5.4% and extracts contained high amounts of unsaturated fatty acids. The addition of ethanol as a co-solvent (40 w/w%) had a slight influence on total phenolic and flavonoid contents increasing their values from 29.1 to 31.5 mg GAE/g and from 2.1 to 4.2 mg QE/g, respectively. The obtained supercritical chamomile extracts showed antioxidant activity achieving values of IC50 around 10 mg/mL. The antimicrobial activity of extracts was most pronounced against Bacillus subtilis. Extracts did not show cytotoxic activity against normal cells. Overall, results indicated a significant potential of extracts from chamomile seeds, produced in an environmentally friendly manner, to be used as a functional food or phytopharmaceuticals.

Green technologies refer to a type of technology that is environmentally friendly based on its production process or its supply chain (i.e resources). Green tech also refers to clean energy production, use of alternative fuels, and processes that are less harmful to the environment compared to ones with fossil fuels. The focus of this presentation is: 1) Processing of polymers obtained from renewable resources that are recyclable and/or biodegradable, 2) Use of environmentally friendly techniques for the preparation of advanced materials (dry porous forms).

Bilberries (Vaccinium myrtillus) have been used in traditional medicine to reduce inflammation and protect against diseases associated with oxidative stress, such as cardiovascular disease, diabetes, and age-related cognitive decline, as well as a remedy for eye conditions. The biological activity of bilberries is ascribed mainly to their high content of anthocyanins, but also to other valuable phytochemicals, including flavonols, phenolic acids, and tannins [1,2]. The enhanced stability and bioavailability of bioactive components from plant material could be accomplished by their incorporation into a polymeric carrier, using the promising integrated processes of supercritical fluid extraction (SFE) and supercritical solvent impregnation (SSI). ...

Natural compounds found in different plant extracts can show numerous biological activities and be used as health promoters. For instance, thymol, carvacrol, citronellol, and eugenol (found in extracts of thyme, oregano, lemongrass, and clove, respectively) can be used as anti-inflammatory, antiviral, and antimicrobial agents [1- 4]. The high volatility of the mentioned natural bioactive compounds (NBCs), which restricts their broader application, can be managed by the incorporation of NBCs into polymer matrices. Therefore, intending to develop devices that release antimicrobial substances in a controlled manner, this study tested the applicability of the supercritical solvent impregnation (SSI) technique for the incorporation of NBCs into starch aerogels. First, the hydrogels were prepared from corn starch. The water in the hydrogels was replaced by ethanol, and the obtained alcogels were dried using the supercritical drying (SCD) technique. The parameters of the aerogels` preparation were optimized previously [5].Later, SSI was performed at 150 bar and 35 °C for 2 h. The obtained materials were analyzed using FTIR, to determine the potential interactions between the NBCs and polymer that could determine the rate of controlled release and antimicrobial activity. Controlled release of NBCs from the aerogels was tested in phosphate-buffered saline solution at 37 °C. ...

Natural compounds found in different plant extracts can show numerous biological activities and be used as health promoters. For instance, thymol, carvacrol, citronellol, and eugenol (found in extracts of thyme, oregano, lemongrass, and clove, respectively) can be used as anti-inflammatory, antiviral, and antimicrobial agents [1- 4]. The high volatility of the mentioned natural bioactive compounds (NBCs), which restricts their broader application, can be managed by the incorporation of NBCs into polymer matrices. Therefore, intending to develop devices that release antimicrobial substances in a controlled manner, this study tested the applicability of the supercritical solvent impregnation (SSI) technique for the incorporation of NBCs into starch aerogels. First, the hydrogels were prepared from corn starch. The water in the hydrogels was replaced by ethanol, and the obtained alcogels were dried using the supercritical drying (SCD) technique. The parameters of the aerogels` preparation were optimized previously [5].Later, SSI was performed at 150 bar and 35 °C for 2 h. The obtained materials were analyzed using FTIR, to determine the potential interactions between the NBCs and polymer that could determine the rate of controlled release and antimicrobial activity. Controlled release of NBCs from the aerogels was tested in phosphate-buffered saline solution at 37 °C. ...

Interest in the separation of green tea extracts continues to grow due to its significant bioactivity, wide applicability as well as a large number of green tea spices, variety of extraction techniques, and lack of systematic data. The present early stage work was intended to estimate the effect of temperature and co-solvent addition on an amount of separated constituents from green tea (gunpowder tea variety, China) during the supercritical carbon dioxide (sc-CO2) extraction process. For this purpose, the temperature of the supercritical extraction process was increased up to 90 °C at a constant pressure of 30 MPa. After the selection of appropriate conditions, co-solvents (ethanol, ethanol/water, and water) were added to sc-CO2. Obtained extracts were analyzed regarding total phenolic content (TPC), total flavonoid content (TFC), DPPH radical scavenging activity, total chlorophyll, and total carotenoid content. The results of the supercritical extraction process were compared with the conventional extraction process (extraction using Soxhlet apparatus). The results showed that a linear decrease in the density of neat sc-CO2 led to a linear increase in extraction yields up to 5.5%. The addition of co-solvents had a variable effect on the amount of separated extracts. While it increased extraction yields at a lower temperature, it decreased extraction yields at a higher temperature. An increase in temperature for the extraction process with neat sc- CO2 also decreased TPC, TFC, chlorophylls, and carotenoids content. The addition of co-solvents to sc-CO2 increased amounts of tested compounds in obtained extracts. It was interesting to notice a decrease in the amount of tested compounds with an increase in water content during extractions. The highest values of TPC and TFC detected were 136.5 mg GAE/g and 40.7 mg QE/g, respectively. Extract solutions with a concentration of 20 mg/mL inhibited up to 65% of DPPH radical. Chlorophyll A, chlorophyll B, and carotenoids wer

This review provides a concise overview of up-to-date developments in the processing of neat poly(lactic acid) (PLA), improvement in its properties, and preparation of advanced materials using a green medium (CO2 under elevated pressure). Pressurized CO2 in the dense and supercritical state is a superior alternative medium to organic solvents, as it is easily available, fully recyclable, has easily tunable properties, and can be completely removed from the final material without post-processing steps. This review summarizes the state of the art on PLA drying, impregnation, foaming, and particle generation by the employment of dense and supercritical CO2 for the development of new materials. An analysis of the effect of processing methods on the final material properties was focused on neat PLA and PLA with an addition of natural bioactive components. It was demonstrated that CO2-assisted processes enable the control of PLA properties, reduce operating times, and require less energy compared to conventional ones. The described environmentally friendly processing techniques and the versatility of PLA were employed for the preparation of foams, aerogels, scaffolds, microparticles, and nanoparticles, as well as bioactive materials. These PLA-based materials can find application in tissue engineering, drug delivery, active food packaging, compostable packaging, wastewater treatment, or thermal insulation, among others.

This study investigates pharmaceutical polymers (Soluplus®, HPMCAS, and Eudragit® E100) and supercritical CO2-assisted process for preparation of floating valsartan delivery systems. Tested process (at pressure of 30 MPa and temperature of 100 °C during 2 h) enabled preparation of stable porous valsartan formulations which was confirmed with FESEM and mercury intrusion porosimetry analysis. The bulk density of obtained formulations was lower than 550 kg/m3. FTIR, DSC, and PXRD analysis indicated that there was no chemical interaction between the drug and polymers and that amorphous solid dispersions were obtained. Formulations with Soluplus® and HPMCAS retained its buoyancy in 0.1 M HCl for longer than 24 h, while formulation with Eudragit® E100 retained its buoyancy up to 2 h. Controlled valsartan release was influenced by solubility of polymers in the tested release medium, which was confirmed by UV/VIS spectroscopy. The obtained results provided framework for further development of floating drug delivery system using an environmental friendly process.

Chitosan/gelatin and chitosan/gelatin/zeolite films prepared by solvent casting method were impregnated with a mixture of thymol and carvacrol using a green solvent, supercritical carbon dioxide at 35 °C and 30 MPa, during 18 h. Proposed method enabled preparation of biocompatible and biodegradable blends with strong antioxidant and antibacterial activity, whereby amounts of loaded thymol/carvacrol mixture were in the range from 3.3-6%. After initial burst release, both types of films exhibited gradual release of bioactive compounds, with around 72 and 96% of impregnated thymol/carvacrol mixture released in water and PBS (pH 7.4) during tested period of 10 days, respectively. Results of water vapor transmission rate (> 76 gm-2 day-1) confirmed that prepared composites are suitable for wound dressing application. Thermal analysis showed superior properties of prepared thymol/carvacrol loaded films compared to control samples. In addition, mechanical and structural properties, as well as solubility and swelling behavior of the obtained films were investigated in detail.

Chitosan/gelatin and chitosan/gelatin/zeolite films prepared by solvent casting method were impregnated with a mixture of thymol and carvacrol using a green solvent, supercritical carbon dioxide at 35 °C and 30 MPa, during 18 h. Proposed method enabled preparation of biocompatible and biodegradable blends with strong antioxidant and antibacterial activity, whereby amounts of loaded thymol/carvacrol mixture were in the range from 3.3-6%. After initial burst release, both types of films exhibited gradual release of bioactive compounds, with around 72 and 96% of impregnated thymol/carvacrol mixture released in water and PBS (pH 7.4) during tested period of 10 days, respectively. Results of water vapor transmission rate (> 76 gm-2 day-1) confirmed that prepared composites are suitable for wound dressing application. Thermal analysis showed superior properties of prepared thymol/carvacrol loaded films compared to control samples. In addition, mechanical and structural properties, as well as solubility and swelling behavior of the obtained films were investigated in detail.

In this work, we examine two modifications of fine-ground calcium carbonate material (GCC) in order to enhanced sorption of NO2 and subsequent reaction properties toward NO2-/NO3- formation by firstly exposing the GCC to supercritical (sc) CO2 in order to increase particle surface area, a choice specifically made to avoid altering the surface chemistry, and secondly considering the potential advantage of using a surface coupling agent toward NO2. The modification by the coupling agent amino silane (AMEO silane) was applied in a supercritical CO2-ethanol mixture. The samples were characterised before and after modification by field emission scanning electron microscopy (FESEM), specific surface area determination (BET nitrogen adsorption), ATR-FTIR spectroscopy and ion chromatography to reveal the effects of the surface modification(s) on the morphology, surface textural properties and sorption versus reaction properties with NO2. The performance of the treated sorbents for NO2 capture was evaluated at room temperature. Results show that reactivity of NO2 with GCC was observed to increase as a function of increased surface area resulting from scCO(2) exposure, but that the presence of AMEO silane on the surface, while enhancing initial adsorption of NO2 was seen subsequently to act to block reactivity. Thus, judicious use of coupling agent can provide desired rapid initial adsorption of the gas, but the goal of long-term CaCO3-consuming reactivity, so as to prolong the uptake of NO2 beyond surface saturation alone, is achieved by increasing surface area while retaining chemical-free exposed CaCO3 surface.

Poly(lactic acid) (PLA) stands out as the most promising biodegradable alternative to conventional petrochemical-based polymers for manufacturing of high-performance materials applied in medicine, pharmacy, food, textile, and electronic industry. This review was aimed to present the conventional and up-to-date technologies for PLA processing including melt blending and molding, hot melt extrusion, 3D printing, foaming, impregnation, thermally induced phase separation, nano- and microparticles preparation, wet and dry spinning processes. In addition, the effect of the processing parameters and polymer characteristics on the properties of the final material was elaborated. Diverse possibilities to tailor properties of PLA-based materials by variation in polymer characteristics and concentration, solvent selection, drying method, processing pressure and temperature, incorporation of bioactive components, and so on were highlighted. The examples of the relations between processing methods, parameters, and end-product properties are given for a better understanding of all aspects that need to be perceived for fabrication of PLA-based materials with required performances.

Outbreak of surgical infections and bacterial resistance against synthetic antibiotic has prompted research towards development of antibacterial medical devices. For that purpose, absorbable surgical sutures were impregnated with natural compound thymol using an environmentally friendly medium. The supercritical solvent impregnation process was performed at 35 degrees C and 10 MPa during 1, 2, 3 and 6 h, resulting in thymol loadings of 3.9-5.6%. All tested samples expressed antibacterial activity against E. coli and S. aureus. Release tests in PBS at 37 degrees C showed that impregnated material released loaded thymol in a gradual manner. While sutures impregnated during 6 h released complete amount of loaded thymol during 6 days, shorter impregnation process resulted in sutures that retained significant thymol amounts (similar to 20-40%) after 10 days of release test. The effect of proposed process on final material properties and its application were explained in detail using characterization techniques SEM, FTIR, DSC and DMA.

The present study was focused on improving the supercritical fluid extraction process dedicated to the recovery of highly valuable extract from Silybum marianum seeds. At first, the process was tested using supercritical CO2 at temperatures of 40 and 80 °C and pressures ranging from 100 to 300 bar. Obtained values were described using two literature models with acceptable agreement of experimental and calculated data. Further, the effect of the equipment design and process scale-up was investigated in four high-pressure units having volumes in the range from 280 mL to 40 L resulting in extraction yields up to 26 %. Based on the values of the parameters determined at the laboratory scale, the extraction process was successfully transferred to a semi-industrial scale. Finally, estimated costs for supercritical extract production in Poland for the year 2021 using a 1000 L high-pressure unit amounted to the price of 35.9 EUR per kg of extract.

The aim of this study was to provide insights into parameters that affect the oil extraction from an industrially valuable raw material (milk thistle) using green solvent supercritical CO2. The effect of plant origin, cultivation year, and seeds storage on extraction yield has been explored. Furthermore, the effects of high-pressure unit design and initial plant material amount have been examined. Pressure (200-450 bar) and temperature (40-80 °C) have been tested to improve the recovery of essential fatty acids and phenolic compounds. Moreover, solid residues after the material pretreatment and supercritical CO2 extraction served as the substrates for waste valorization. The characterization of obtained high-value extracts has been carried out by chromatographic (using gas chromatographs combined with mass spectrometer and flame ionization detection) and spectrophotometric assays (for total phenolic and flavonoid compounds as well as a radical scavenging ability). It was shown that the tested supercritical CO2 extraction process parameters determined extraction kinetics and allowed the extract separation from raw milk thistle seeds and waste material (3-32 mass %) rich in linoleic acid (up to 515 mg/g) and total phenolic compounds (up to 30 mg GAE/g).

Dandelion (Taraxacum officinale) is becoming an industry valuable crop due to the increase in its utilization in the food and phytopharmaceutical industry. Nonetheless, its application is still limited especially considering its extracts. Therefore, this study was aimed at exploring dandelion seeds as a source of bioactive compounds. For this purpose, an environmentally friendly supercritical CO2 extraction technique was employed and extracts were separated at pressures of 10-45 MPa and a temperature of 313 K. Obtained extracts were characterized using a gas chromatograph equipped with mass spectroscopy (GC-MS), a gas chromatograph equipped with flame ionization detector (CGFID), as well as by Folin–Ciocalteu and DPPH assays using a UV/VIS spectrophotometer. It was shown that the selection of process pressure determined both extract yield and extract composition. An increase in pressure increased extraction yield from 7.4 to 25.2% and the content of dominant linoleic and oleic fatty acids (from 536.3 to 658.3 mg/g and 125.8 to 161.7 mg/g, respectively). Total phenolic and flavonoid content in obtained extracts ranged from 5.5 to 9.0 mg GAE/g and from 208.6 to 497.5 mg QE/g, respectively. The strongest DPPH radical scavenging activity with inhibition of 64.4% was recorded for extract obtained at 10 MPa for extract solution concentration of 20 mg/mL. Obtained results confirmed that extracts obtained from dandelion seeds are a valuable source of bioactive compounds.

Plant milk thistle (Silybum marianum, Asteraceae) is a source of valuable bioactive compounds such as essential fatty acids and flavonolignans, that are commercially used in food and phytopharmaceuticals. These bioactive compounds are separated from plant material by conventional extraction methods using organic solvents such as n-hexane and high temperatures. In this manner bioactive compounds can be thermally degraded, organic solvent can remain in final products, and organic waste is generated. A green alternative to conventional extraction techniques is the supercritical extraction process (SCE), which employs CO2 as a solvent. Supercritical CO2 (scCO2) has GRAS status and relatively mild critical parameters (Pc= 7.3 MPa and Tc=31.1 °C). Due to high diffusivity, low viscosity, and near-zero surface tension, it is widely used for the separation of bioactive compounds from plant material. It can be easily separated from the final product and fully recycled. In order to produce a high amount of valuable extract from milk thistle seeds in an environmentally friendly manner, the SCE process was tested at pressures of 10, 20, 30, and 45 MPa and temperatures 40, 60, and 80°C. Obtained extracts were characterized using a gas chromatograph equipped with mass spectroscopy (GC-MS), a gas chromatograph equipped with flame ionization detector (CG-FID), as well as by Folin–Ciocalteu and DPPH assays. It was shown that variation of the extraction pressure and temperature led to a significant variation in extraction yields (from 0.1 to 31.5%). Furthermore, the content of dominant essential fatty acid (linoleic acid) present in extracts ranged from 445 to 514mg/g. It was shown that the extract separated at 10 MPa and 40°C contained the highest amount of total phenolic compounds (138.0 mg GAE/g). The highest DPPH radical scavenging activity (IC50=12.66 mg/mL) showed the extract obtained at 30MPa and 60°C. Obtained results gave valuable insights into the optimization of the SCE pro

Milk thistle (Silybum marianum, Asteraceae) is a plant used in traditional medicine from ancient times mostly for treatment of liver disorders [1,2]. Nowadays it is an industrially valuable crop for preparation of herbal supplements reaching total sales of 16 million USD in the USA market [2]. The separation of valuable bioactive compounds from plant materials can be performed by several methods using organic and inorganic solvents. Nevertheless, supercritical fluid extraction (SFE) that employs CO2 is considered a green alternative to other conventional extraction methods. In order to be economically viable, the SFE process should be optimized by selection of appropriate pressure and temperature conditions followed by a scale-up. The scale-up of the SFE process can be performed by keeping constant: the ratio of scCO2 flow rate to mass of bed raw material, the ratio of bed length and bed diameter or dimensionless number such as Reynolds number [3]. This study presents the scale-up of the SFE process, first by selection of optimal pressure (100, 200 and 300 bar) at moderate temperature of 40 °C using a lab scale unit (0.6 L), following by selection of optimal CO2 consumption per used plant material as well as optimal ratio of plant material mass per volume of extractor. Optimal parameters were further tested using a semi-industrial scale unit (40 L). The highest extraction yield obtained was 27%. The performed scale-up study showed a good agreement between lab and pilot scale units. The qualitative analysis performed using GC/MS showed that obtained extracts contained around 80% of unsaturated fatty acids. The quantitative analysis performed using GC/FID confirmed that predominant fatty acids were oleic and linoleic acids with a content in the range of 191-234 mg/g and 445-514 mg/g, respectively (depending on the SFE pressure). Total phenolic compounds were estimated in each extract by the Folin–Ciocalteu assay reaching ca. 90 mg GAE/g. The free radical scavenging ca

Polylactide (PLA) is a versatile polymer with a variety of applications from consumer goods (e.g. disposable cutlery, food, and beverage packaging) to medical (e.g. disposable protective garments, implants), agriculture (e.g. mulch films), etc [1]. However, its use as porous materials is still limited [2]. In order to increase possible PLA-based material applications, the present work was focused on the preparation of PLA aerogels with defined morphology. For this purpose, three polymer solvents were tested (chloroform, dichloromethane, and dioxane). PLA solutions, prepared at room temperature, were immersed in antisolvent (absolute ethanol) for solvent replacement prior to drying. Obtained alcogels were dried using supercritical CO 2 at 150 bar and 35 °C in a combination of static and dynamic regimes up to 3 h [3] for aerogel production. While chloroform and dichloromethane enabled the production of stable material, the use of dioxane as a solvent led to the formation of aerogels that were crumbling during retrieving from a high-pressure drying unit. Stable aerogels were further characterized using scanning electron microscopy, water displacement method, mercury intrusion porosimetry, gas adsorption-desorption analysis as well as Fourier transform infrared spectroscopy and thermogravimetry combined with differential scanning calorimetry. After the selection of optimal solvent, two temperatures for solvent replacement with anti-solvent ethanol were compared (-20 and 22 °C). Results showed that both solvent selection as well as temperature for solvent replacement have a significant effect on the morphology of PLA aerogels. The density of aerogels ranged from 0.34 to 0.47 g/cm3 while its porosity ranged from 62.6 to 73.0% [3].

Bilberries (Vaccinium myrtillus) are believed to have one of the highest antioxidant levels of all common fruits and vegetables. As a source of antioxidants, they have been used in traditional medicine to reduce inflammation and protect against diseases associated with oxidative stress, such as cardiovascular disease, diabetes, and age-related cognitive decline, as well as a remedy for eye conditions. The biological activity of bilberries is associated with the high content of anthocyanins, a large group of water-soluble flavonoids. Besides the complex anthocyanin profile, bilberries also contain other phenolic compounds including flavonols, tannins, and phenolic acids. Supercritical fluid extraction (SFE) isa a green and environmentally friendly process based on the use of supercritical fluids, most commonly CO2, as an alternative to organic solvents, to obtain solvent-free and highly valuable plant extracts. Utilization of supercritical CO2 (scCO2) extraction also enables the preservation of thermally labile compounds working at low temperatures, and good selectivity accomplished by the appropriate choice of operating pressure and temperature. In this study, scCO2 extraction was investigated as a method for isolating the extract from bilberry dried fruit. Extractions were performed at temperature of 70 °C and pressures of 15 and 30 MPa, with and without the ethanol as co-solvent, with the aim to optimize the yield of the obtained extract based on the composition. The obtained extraction yields ranged from 1.2 to 7% and the highest yield was obtained, as expected, at a higher pressure of 30 MPa. The effect of ethanol as co-solvent in the scCO2 extraction was studied with the goal to modify scCO2 selectivity and enhance the solubility of polar substances. The results showed a positive effect on the extraction yield, while total phenolic content (TPC) analysis revealed that extracts obtained using co-solvent have higher TPC values. Chemical analysis of the obtained e

Cannabis sativa is one of the oldest plant cultures, which has been used for centuries as a source of textile fibres, for paper production, as well as a source of bioactive compounds used in medicine. Although being restrained for a long time, its high potential, coupled with the progress in legislation and/or legalization in some regions of the world, led to the significant increase of scientific research towards isolation of cannabinoids, primarily a non-psychotropic cannabidiol (CBD), over the past couple decades. Beside cannabinoids, found only in cannabis plants, Cannabis sativa is characterized by very complex chemical composition with almost 500 constituents, including terpenes, flavonoids, phenolic compounds and fatty acids [2]. The co-presence of these numerous molecules in preparations obtained from Cannabis sativa may lead to a greater biological activity due to the “entourage” or synergistic effect [3]. CBD has attracted considerable interest due to its numerous therapeutic properties and pharmacological activities [1]. However, cannabinoids are characterized by a low solubility in aqueous media and, as a consequence, a relatively poor bioavailability. Therefore, improvement of their stability, shelf-life and bioavailability, by incorporation into biocompatible carriers is still a challenge. As an answer to this issue, integrated process of supercritical fluid extraction (SFE) from Cannabis sativa and supercritical solvent impregnation (SSI) of obtained extract into starch aerogel was tested. Starch gels were prepared starting from hydrogel formed from an aqueous solution of cornstarch (1:10 w/v). During replacement of water with acetone, by successive increase of its concentration until 100%, acetogel was formed and further subjected to drying using supercritical CO2 (scCO2) at 45 °C and 8-10 MPa to obtain aerogel. For comparison, a part of acetogel was dried in the oven at 60 °C to obtain xerogel. Textural properties and morphology of prepared material

Supercritical carbon dioxide (scCO2) application in the pharmaceutical industry is still undeveloped regardless of significant research interests in this processing medium shown in the last decades. ScCO2 technologies can improve drug solubility, bioavailability, and therapeutic effect. These technologies can lead to the development of new formulations that will contribute to a decrease in drug dose, medication frequency, and increase patients’ well-being. Considering the significant decrease in the price of high-pressure equipment and society's growing need for cleaner production and safer products, it is expected that symbiosis between supercritical fluid and pharmaceutical technologies will happen soon. Therefore, this review was focused on the latest contributions of scCO2 technologies to the pharmaceutical field. The main aim was to bring these technologies closer to pharmaceutical specialists. For this purpose, the most commonly used technologies were explained and discussed: the preparation of solid dispersions, polymer impregnation with drugs, and drug micro/nanoparticle production using scCO2.

In this work, we examine two modifications of fine-ground calcium carbonate material (GCC) in order to enhanced sorption of NO2 and subsequent reaction properties toward NO2-/NO3- formation by firstly exposing the GCC to supercritical (sc) CO2 in order to increase particle surface area, a choice specifically made to avoid altering the surface chemistry, and secondly considering the potential advantage of using a surface coupling agent toward NO2. The modification by the coupling agent amino silane (AMEO silane) was applied in a supercritical CO2-ethanol mixture. The samples were characterised before and after modification by field emission scanning electron microscopy (FESEM), specific surface area determination (BET nitrogen adsorption), ATR-FTIR spectroscopy and ion chromatography to reveal the effects of the surface modification(s) on the morphology, surface textural properties and sorption versus reaction properties with NO2. The performance of the treated sorbents for NO2 capture was evaluated at room temperature. Results show that reactivity of NO2 with GCC was observed to increase as a function of increased surface area resulting from scCO(2) exposure, but that the presence of AMEO silane on the surface, while enhancing initial adsorption of NO2 was seen subsequently to act to block reactivity. Thus, judicious use of coupling agent can provide desired rapid initial adsorption of the gas, but the goal of long-term CaCO3-consuming reactivity, so as to prolong the uptake of NO2 beyond surface saturation alone, is achieved by increasing surface area while retaining chemical-free exposed CaCO3 surface.

The present study was focused on improving the supercritical fluid extraction process dedicated to the recovery of highly valuable extract from Silybum marianum seeds. At first, the process was tested using supercritical CO2 at temperatures of 40 and 80 °C and pressures ranging from 100 to 300 bar. Obtained values were described using two literature models with acceptable agreement of experimental and calculated data. Further, the effect of the equipment design and process scale-up was investigated in four high-pressure units having volumes in the range from 280 mL to 40 L resulting in extraction yields up to 26 %. Based on the values of the parameters determined at the laboratory scale, the extraction process was successfully transferred to a semi-industrial scale. Finally, estimated costs for supercritical extract production in Poland for the year 2021 using a 1000 L high-pressure unit amounted to the price of 35.9 EUR per kg of extract.

Chitosan/gelatin and chitosan/gelatin/zeolite films prepared by solvent casting method were impregnated with a mixture of thymol and carvacrol using a green solvent, supercritical carbon dioxide at 35 °C and 30 MPa, during 18 h. Proposed method enabled preparation of biocompatible and biodegradable blends with strong antioxidant and antibacterial activity, whereby amounts of loaded thymol/carvacrol mixture were in the range from 3.3-6%. After initial burst release, both types of films exhibited gradual release of bioactive compounds, with around 72 and 96% of impregnated thymol/carvacrol mixture released in water and PBS (pH 7.4) during tested period of 10 days, respectively. Results of water vapor transmission rate (> 76 gm-2 day-1) confirmed that prepared composites are suitable for wound dressing application. Thermal analysis showed superior properties of prepared thymol/carvacrol loaded films compared to control samples. In addition, mechanical and structural properties, as well as solubility and swelling behavior of the obtained films were investigated in detail.

Chitosan/gelatin and chitosan/gelatin/zeolite films prepared by solvent casting method were impregnated with a mixture of thymol and carvacrol using a green solvent, supercritical carbon dioxide at 35 °C and 30 MPa, during 18 h. Proposed method enabled preparation of biocompatible and biodegradable blends with strong antioxidant and antibacterial activity, whereby amounts of loaded thymol/carvacrol mixture were in the range from 3.3-6%. After initial burst release, both types of films exhibited gradual release of bioactive compounds, with around 72 and 96% of impregnated thymol/carvacrol mixture released in water and PBS (pH 7.4) during tested period of 10 days, respectively. Results of water vapor transmission rate (> 76 gm-2 day-1) confirmed that prepared composites are suitable for wound dressing application. Thermal analysis showed superior properties of prepared thymol/carvacrol loaded films compared to control samples. In addition, mechanical and structural properties, as well as solubility and swelling behavior of the obtained films were investigated in detail.

The aim of this study was to provide insights into parameters that affect the oil extraction from an industrially valuable raw material (milk thistle) using green solvent supercritical CO2. The effect of plant origin, cultivation year, and seeds storage on extraction yield has been explored. Furthermore, the effects of high-pressure unit design and initial plant material amount have been examined. Pressure (200-450 bar) and temperature (40-80 °C) have been tested to improve the recovery of essential fatty acids and phenolic compounds. Moreover, solid residues after the material pretreatment and supercritical CO2 extraction served as the substrates for waste valorization. The characterization of obtained high-value extracts has been carried out by chromatographic (using gas chromatographs combined with mass spectrometer and flame ionization detection) and spectrophotometric assays (for total phenolic and flavonoid compounds as well as a radical scavenging ability). It was shown that the tested supercritical CO2 extraction process parameters determined extraction kinetics and allowed the extract separation from raw milk thistle seeds and waste material (3-32 mass %) rich in linoleic acid (up to 515 mg/g) and total phenolic compounds (up to 30 mg GAE/g).

Outbreak of surgical infections and bacterial resistance against synthetic antibiotic has prompted research towards development of antibacterial medical devices. For that purpose, absorbable surgical sutures were impregnated with natural compound thymol using an environmentally friendly medium. The supercritical solvent impregnation process was performed at 35 degrees C and 10 MPa during 1, 2, 3 and 6 h, resulting in thymol loadings of 3.9-5.6%. All tested samples expressed antibacterial activity against E. coli and S. aureus. Release tests in PBS at 37 degrees C showed that impregnated material released loaded thymol in a gradual manner. While sutures impregnated during 6 h released complete amount of loaded thymol during 6 days, shorter impregnation process resulted in sutures that retained significant thymol amounts (similar to 20-40%) after 10 days of release test. The effect of proposed process on final material properties and its application were explained in detail using characterization techniques SEM, FTIR, DSC and DMA.

Poly(lactic acid) (PLA) stands out as the most promising biodegradable alternative to conventional petrochemical-based polymers for manufacturing of high-performance materials applied in medicine, pharmacy, food, textile, and electronic industry. This review was aimed to present the conventional and up-to-date technologies for PLA processing including melt blending and molding, hot melt extrusion, 3D printing, foaming, impregnation, thermally induced phase separation, nano- and microparticles preparation, wet and dry spinning processes. In addition, the effect of the processing parameters and polymer characteristics on the properties of the final material was elaborated. Diverse possibilities to tailor properties of PLA-based materials by variation in polymer characteristics and concentration, solvent selection, drying method, processing pressure and temperature, incorporation of bioactive components, and so on were highlighted. The examples of the relations between processing methods, parameters, and end-product properties are given for a better understanding of all aspects that need to be perceived for fabrication of PLA-based materials with required performances.

Chitosan/gelatin and chitosan/gelatin/zeolite films prepared by solvent casting method were impregnated with a mixture of thymol and carvacrol using a green solvent, supercritical carbon dioxide at 35 °C and 30 MPa, during 18 h. Proposed method enabled preparation of biocompatible and biodegradable blends with strong antioxidant and antibacterial activity, whereby amounts of loaded thymol/carvacrol mixture were in the range from 3.3-6%. After initial burst release, both types of films exhibited gradual release of bioactive compounds, with around 72 and 96% of impregnated thymol/carvacrol mixture released in water and PBS (pH 7.4) during tested period of 10 days, respectively. Results of water vapor transmission rate (> 76 gm-2 day-1) confirmed that prepared composites are suitable for wound dressing application. Thermal analysis showed superior properties of prepared thymol/carvacrol loaded films compared to control samples. In addition, mechanical and structural properties, as well as solubility and swelling behavior of the obtained films were investigated in detail.

Chitosan/gelatin and chitosan/gelatin/zeolite films prepared by solvent casting method were impregnated with a mixture of thymol and carvacrol using a green solvent, supercritical carbon dioxide at 35 °C and 30 MPa, during 18 h. Proposed method enabled preparation of biocompatible and biodegradable blends with strong antioxidant and antibacterial activity, whereby amounts of loaded thymol/carvacrol mixture were in the range from 3.3-6%. After initial burst release, both types of films exhibited gradual release of bioactive compounds, with around 72 and 96% of impregnated thymol/carvacrol mixture released in water and PBS (pH 7.4) during tested period of 10 days, respectively. Results of water vapor transmission rate (> 76 gm-2 day-1) confirmed that prepared composites are suitable for wound dressing application. Thermal analysis showed superior properties of prepared thymol/carvacrol loaded films compared to control samples. In addition, mechanical and structural properties, as well as solubility and swelling behavior of the obtained films were investigated in detail.

Poly(lactic acid) (PLA) stands out as the most promising biodegradable alternative to conventional petrochemical-based polymers for manufacturing of high-performance materials applied in medicine, pharmacy, food, textile, and electronic industry. This review was aimed to present the conventional and up-to-date technologies for PLA processing including melt blending and molding, hot melt extrusion, 3D printing, foaming, impregnation, thermally induced phase separation, nano- and microparticles preparation, wet and dry spinning processes. In addition, the effect of the processing parameters and polymer characteristics on the properties of the final material was elaborated. Diverse possibilities to tailor properties of PLA-based materials by variation in polymer characteristics and concentration, solvent selection, drying method, processing pressure and temperature, incorporation of bioactive components, and so on were highlighted. The examples of the relations between processing methods, parameters, and end-product properties are given for a better understanding of all aspects that need to be perceived for fabrication of PLA-based materials with required performances.

In this work, we examine two modifications of fine-ground calcium carbonate material (GCC) in order to enhanced sorption of NO2 and subsequent reaction properties toward NO2-/NO3- formation by firstly exposing the GCC to supercritical (sc) CO2 in order to increase particle surface area, a choice specifically made to avoid altering the surface chemistry, and secondly considering the potential advantage of using a surface coupling agent toward NO2. The modification by the coupling agent amino silane (AMEO silane) was applied in a supercritical CO2-ethanol mixture. The samples were characterised before and after modification by field emission scanning electron microscopy (FESEM), specific surface area determination (BET nitrogen adsorption), ATR-FTIR spectroscopy and ion chromatography to reveal the effects of the surface modification(s) on the morphology, surface textural properties and sorption versus reaction properties with NO2. The performance of the treated sorbents for NO2 capture was evaluated at room temperature. Results show that reactivity of NO2 with GCC was observed to increase as a function of increased surface area resulting from scCO(2) exposure, but that the presence of AMEO silane on the surface, while enhancing initial adsorption of NO2 was seen subsequently to act to block reactivity. Thus, judicious use of coupling agent can provide desired rapid initial adsorption of the gas, but the goal of long-term CaCO3-consuming reactivity, so as to prolong the uptake of NO2 beyond surface saturation alone, is achieved by increasing surface area while retaining chemical-free exposed CaCO3 surface.

Outbreak of surgical infections and bacterial resistance against synthetic antibiotic has prompted research towards development of antibacterial medical devices. For that purpose, absorbable surgical sutures were impregnated with natural compound thymol using an environmentally friendly medium. The supercritical solvent impregnation process was performed at 35 degrees C and 10 MPa during 1, 2, 3 and 6 h, resulting in thymol loadings of 3.9-5.6%. All tested samples expressed antibacterial activity against E. coli and S. aureus. Release tests in PBS at 37 degrees C showed that impregnated material released loaded thymol in a gradual manner. While sutures impregnated during 6 h released complete amount of loaded thymol during 6 days, shorter impregnation process resulted in sutures that retained significant thymol amounts (similar to 20-40%) after 10 days of release test. The effect of proposed process on final material properties and its application were explained in detail using characterization techniques SEM, FTIR, DSC and DMA.

This study investigates pharmaceutical polymers (Soluplus((R)), HPMCAS, and Eudragit((R)) E100) and supercritical CO2-assisted process for preparation of floating valsartan delivery systems. Tested process (at pressure of 30 MPa and temperature of 100 degrees C during 2 h) enabled preparation of stable porous valsartan formulations which was confirmed with FESEM and mercury intrusion porosimetry analysis. The bulk density of obtained formulations was lower than 550 kg/m(3). FTIR, DSC, and PXRD analysis indicated that there was no chemical interaction between the drug and polymers and that amorphous solid dispersions were obtained. Formulations with Soluplus((R)) and HPMCAS retained its buoyancy in 0.1 M HCl for longer than 24 h, while formulation with Eudragit((R)) E100 retained its buoyancy up to 2 h. Controlled valsartan release was influenced by solubility of polymers in the tested release medium, which was confirmed by UV/VIS spectroscopy. The obtained results provided framework for further development of floating drug delivery system using an environmental friendly process.

The release of industrial wastewater into the ecosystem prompted our research on the development of an efficient and biodegradable material that can be used for wastewater treatment. We optimized preparation of porous material from poly(lactic acid) (PLA) by variation in solvents and drying methods (air-drying vs. supercritical CO2-drying). In addition, we optimized the method of TiO2 nanoparticles immobilization (in situ vs. ex situ) onto porous PLA. The material properties and functionality were verified by SEM, water displacement, gas adsorption desorption, Hg-intrusion porosimetry, dye degradation, FTIR, TGA/DSC, and water contact angle analysis. We showed that the morphology of PLA material could be controlled by variation in process parameters resulting in porosity from 43% to 73%. The prepared material sustained floatability for longer than 4 weeks and provided complete discoloration of dye C.I. Acid Orange 7 after 240 min of illumination. The high photocatalytic activity was preserved within three repeated cycles.