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This study aimed to develop an improved sustained‐release (SR) PLGA microsphere of exenatide using supercritical fluid extraction of emulsions (SFEE). As a translational research, we investigated the effect of various process parameters on the fabrication of exenatide‐loaded PLGA microspheres by SFEE (ELPM_SFEE) using the Box–Behnken design (BBD), a design of experiment approach. Further, ELPM obtained under optimized conditions and satisfying all the response criteria were compared with PLGA microspheres prepared using the conventional solvent evaporation (ELPM_SE) method through various solid‐state characterizations and in vitro and in vivo evaluations. The four process parameters selected as independent variables were pressure (X1), temperature (X2), stirring rate (X3), and flow ratio (X4). The effects of these independent variables on five responses, namely the particle size, its distribution (SPAN value), encapsulation efficiency (EE), initial drug burst release (IBR), and residual organic solvent, were evaluated using BBD. Based on the experimental results, a desirable range of combinations of various variables in the SFEE process was determined by graphical optimization. Solid‐state characterization and in vitro evaluation revealed that ELPM_SFEE improved properties, including a smaller particle size and SPAN value, higher EE, lower IBR, and lower residual solvent. Furthermore, the pharmacokinetic and pharmacodynamic study results indicated better in vivo efficacy with desirable SR properties, including a reduction in blood glucose levels, weight gain, and food intake, for ELPM_SFEE than those generated using SE. Therefore, the potential drawback of conventional technologies such as the SE for the preparation of injectable SR PLGA microspheres could be improved by optimizing the SFEE process. [ABSTRACT FROM AUTHOR]

The results of comparative analysis for the key factors of the mechanism of oil-recovery enhancement with the use of gases in a supercritical fluid state as applied to carbon dioxide and propane (propane/butane mixtures) are presented. The above-mentioned factors as a subject of consideration incorporate the dissolving ability of compressed gases with respect to oil and its components, the phase behavior of binary systems containing the mentioned displacing agents and oil hydrocarbons, the critical parameters for the binary systems of fluid-phase behavior types I–II, the compressibility of carbon dioxide and propane under oil-displacement process conditions in tertiary oil production, the viscosity of the media participating in the discussed process and, finally, the swelling of oil as a result of its saturation with a gas. The results of experimental implementation under supercritical fluid conditions are given for an extraction oil-recovery process with carbon dioxide as an extragent in one case and propane in the other case. It is established that propane and propane/butane mixtures are three or more times superior to CO2 in dissolving ability with respect to oil components under displacement-process conditions; that they more often form systems of fluid-phase behavior types I–II with the oil components, which is preferable for the process of its recovery; that the compressor power spent on the compression of carbon dioxide and methane is threefold or more higher than for propane; and, finally, that propane has a much lower viscosity under oil-displacement conditions. In sum, propane and propane/butane mixtures are preferable for use in the oil-displacement process within the framework of tertiary oil production. [ABSTRACT FROM AUTHOR]

The application of dense gases in particle formation processes has attracted great attention due to documented advantages over conventional technologies. In particular, the use of dense CO2 in the process has been subject of many works and explored in a variety of different techniques. This article presents a review of the current available techniques in use in particle formation processes, focusing exclusively on those employing dense CO2 as a solute, co-solute or co-solvent during the process, such as PGSS (Particles from gas-saturated solutions®), CPF (Concentrated Powder Form®), CPCSP (Continuous Powder Coating Spraying Process), CAN-BD (Carbon dioxide Assisted Nebulization with a Bubble Dryer®), SEA (Supercritical Enhanced Atomization), SAA (Supercritical Fluid-Assisted Atomization), PGSS-Drying and DELOS (Depressurization of an Expanded Liquid Organic Solution). Special emphasis is given to modifications introduced in the different techniques, as well as the limitations that have been overcome. [ABSTRACT FROM AUTHOR]

Literature data on basic research for and practical application of the synthesis of micro- and nanoparticles with the use of supercritical fluids (SCFs) are systematized and analyzed. The review of SCF-based micronization is divided into sections according to the role played by an SCF in the process, which is in most cases a solvent (the rapid expansion of supercritical solutions (RESS)), an antisolvent (supercritical antisolvent precipitation (SAS)), or a solute (particles formed from gas-saturated solutions (PGSS)). Special attention is given to means less covered in the literature, where the SCF is a co-solute (SAA, CAN-BD, and DELOS). The main advantages, limitations, and applicability of each approach for a specific range of substances are analyzed in detail. It is shown that the range of the considered substances is not limited to the best-described pharmaceutical objects; rather, it is greatly expanded to cover possible applications of SCF micronization. The focus is mainly on works published over the last decade. [ABSTRACT FROM AUTHOR]

Over the last century, polymer processes involving a gas or supercritical fluid (SCF) have attracted significant attention.  The attributes of a gas/SCF in polymers benefited many polymer processing applications.  In polymer applications, the solubility and diffusivity of the gas/SCF in polymers are important parameters.  This review discusses experimental and theoretical methods for determining gas/SCF solubility and diffusivity in polymers.  The Henry's law, Flory-Huggins, Sanchez-Lacombe, Simha-Somcynsky, and statistical association fluid theories are discussed for gas/SCF solubility in polymers.  The experimental methods are categorized into five: gravimetric, piezoelectric, manometric, chromatographic, and spectroscopic methods, and are compared in terms of the operating temperatures, pressures, and types of a gas/SCF. The solubility from different methods in literatures has been compared in summary plots. In addition, the main advantages and disadvantages of each of the measurement methods are tabulated. In the diffusivity section, the steady and unsteady diffusion including the Crank's, dual-mode sorption, gas-polymer matrix, free volume, mass transfer, and empirical models are reviewed. For unsteady diffusion, the pressure decay and the gravimetric method are discussed. For steady state diffusion, the permeation method is discussed as the experimental methods. The different methods used for obtaining information on diffusivity are tabulated for comparisons. [ABSTRACT FROM AUTHOR]

Standard drug delivery systems for cancer treatment usually comprise a device with a specific size and shape (depending on the type of cancer that has to be treated), which is composed by a biodegradable compound with a chemotherapeutic entrapped within it. This device should have a molecule (mainly a protein) bound to its surface to target only cancer cells. On the contrary, supercritical fluids (SCF) have been widely used in the pharmaceutical industry for creating drug delivery systems or for extracting drugs from natural sources. This review explains the potential of SCFs for cancer therapies by studying the current uses of the different high-pressure processes that can be useful for this medical treatment, such as the development of new drug delivery systems (with their drug release) or the extraction of chemotherapeutics from a vegetal matrix. [ABSTRACT FROM AUTHOR]

Copyright of Gazette of Chemists, Technologists & Environmentalists of Republic of Srpska / Glasnik Hemicara, Tehnologa i Ekologa Republike Srpske is the property of University of Banja Luka, Faculty of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Context: Supercritical fluid methods offer an alternative to conventional mixing methods, particularly for heat sensitive drugs and where an organic solvent is undesirable. Objective: To design, develop and construct a unit for the particles from a gas-saturated suspension/solution (PGSS) method and form endogenous progesterone (PGN) dispersion systems using SC-CO2. Materials and methods: The PGN dispersions were manufactured using three selected excipients: polyethylene glycol (PEG) 400/4000 (50:50), Gelucire 44/14 and D-α-tocopheryl PEG 1000 succinate (TPGS). Semisolid dispersions of PGN prepared by PGSS method were compared to the conventional methods; comelting (CM), cosolvent (CS) and physical mixing (PM). The dispersion systems made were characterized by Raman and Fourier transform infrared (FTIR) spectroscopies, X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), PGN recovery, uniformity and in vitro dissolution, analyzed by high-performance liquid chromatography (HPLC). Results: Raman spectra revealed no changes in the crystalline structure of PGN treated with SC-CO2 compared to that of untreated PGN. XRPD and FTIR showed the presence of peaks and bands for PGN confirming that PGN has been incorporated well with each individual excipient. All PGN dispersions prepared by the PGSS method resulted in the improvement of PGN dissolution rates compared to that prepared by the conventional methods and untreated PGN after 60 min ( p value < 0.05). Conclusion: The novel PGN dispersions prepared by the PGSS method offer the great potential to enhance PGN dissolution rate, reduce preparation time and form stable crystalline dispersion systems over those prepared by conventional methods. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum: Technology is the property of Universidade Estadual de Maringa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Supercritical fluids possess the unique properties of behaving like liquids and gases, above their critical point. Supercritical fluid technology has recently emerged as a green and novel technique for various processes such as solubility enhancement of poorly soluble drugs, plasticization of polymers, surface modification, nanosizing and nanocrystal modification, and chromatographic extraction. Research interest in this area has been fuelled because of the numerous advantages that the technology offers over the conventional methods. This work aims to review the merits, demerits, and various processes such as rapid expansion of supercritical solutions (RESS), particles from gas saturated solutions (PGSS), gas antisolvent process (GAS), supercritical antisolvent process (SAS) and polymerization induced phase separation (PIPS), that have enabled this technology to considerably raise the interest of researchers over the past two decades. An insight has been given into the numerous applications of this technology in pharmaceutical industry and the future challenges which must be appropriately dealt with to make it effective on a commercial scale. [ABSTRACT FROM AUTHOR]

Using the CO2-and N2-assisted atomization processes, the production of ibuprofen/lipid composite microparticles is investigated, in which the lipid includes myristic acid and tripalmitin. The produced composite particles show similar morphology to that of the purelipids obtained by the same process. In the case of the N2-assisted process, the average size of composite particles is slightly larger than that of the pure lipid particles due to the difficulty of solidification when using N2. In the case of the CO2-assisted process, the average size of composite particles is slightly smaller than that of the pure myristic acid particles, but slightly larger than that of the pure tripalmitin particles. The dissolution study reveals that the drug release from the ibuprofen/myristic acid particles is enhanced in comparison with that of the unprocessed ibuprofen. For the particles produced by the N2-assisted process, the X-ray diffraction (XRD) patterns clearly indicate the encapsulation of ibuprofen into myristic acid. The obtained ibuprofen/tripalmitin composite particles with 5% or 20% of ibuprofen (in mass) evidently show the controlled drug release: only about 20% of the drug is released in 500 min from the ibuprofen/tripalmitin composite particles consisting of 20% ibuprofen prepared by the CO2-assisted process, and the same release is obtained from the ibuprofen/tripalmitin composite particles containing 5% ibuprofen prepared by the N2-assisted process. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the possibility of preparing solid dispersions of the poorly soluble budesonide by supercritical fluid (SCF) technique, using poly (ethylene oxide) (PEO) as a hydrophilic carrier. The budesonide-PEO solid dispersions were prepared, using supercritical carbon dioxide (SC CO2) as the processing medium, and characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), solubility test and dissolution test in order to understand the influence of the SCF process on the physical status of the drug. The endothermic peak of budesonide in the SCF-treated mixtures was significantly reduced, indicating that budesonide was in amorphous form inside the carrier system. This was further confirmed by SEM and PXRD studies. The enhanced dissolution rates of budesonide were observed from SCF-treated budesonide-PEO mixtures. The amorphous characteristic of the budesonide, the better mixing of drug and PEO powders in the presence of SC CO2, together with the improved wettability of the drug in PEO, produced a remarkable enhancement of the in vitro drug dissolution rate. Thus, budesonide-PEO solid dispersions with enhanced dissolution rate can be prepared using organic solvent-free SCF process. [ABSTRACT FROM AUTHOR]

This article serves as an overview, introducing the currently popular area of supercritical fluids (SFs) and their uses in biotechnology and related areas. It covers the fundamentals of supercritical science and moves on to the biotechnological and associated applications of these fluids. Subject areas covered include pure substances as supercritical fluids, the properties of supercritical fluids, organic cosolvents, solubility, and the following applications: extraction, chromatography, reactions, particle production, deposition, and the drying of biological specimens. Within each application, and where possible, the basic principles of the technique are given, as well as a description of the history, instrumentation, methodology, uses, problems encountered, and advantages over the traditional, nonsupercritical methods. [ABSTRACT FROM AUTHOR]

Drug delivery systems (DDS) often comprise biopharmaceuticals in aqueous form, making them susceptible to physical and chemical degradation, and therefore requiring low temperature storage in cold supply and distribution chains. Freeze-drying, spray-drying, and spray-freeze-drying are some of the techniques used to convert biopharmaceuticals-loaded DDS from aqueous to solid dosage forms. However, the risk exists that shear and heat stress during processing may provoke DDS damage and efficacy loss. Supercritical fluids (SCF), specifically, supercritical carbon dioxide (scCO2), is a sustainable alternative to common techniques. Due to its moderately critical and tunable properties and thermodynamic behavior, scCO2 has aroused scientific and industrial interest. Therefore, this article reviews scCO2-based techniques used over the year in the production of solid biopharmaceutical dosage forms. Looking particularly at the use of scCO2 in each of its potential roles—as a solvent, co-solvent, anti-solvent, or co-solute. It ends with a comparison between the compound's stability using supercritical CO2-assisted atomization/spray-drying and conventional drying. [ABSTRACT FROM AUTHOR]

Micro-/nanoparticle formulations containing drugs with or without various biocompatible excipients are widely used in the pharmaceutical field to improve the physicochemical and clinical properties of the final drug product. Among the various micro-/nanoparticle production technologies, emulsion-based particle formation is the most widely used because of its unique advantages such as uniform generation of spherical small particles and higher encapsulation efficiency (EE). For this emulsion-based micro-/nanoparticle technology, one of the most important factors is the extraction efficiency associated with the fast removal of the organic solvent. In consideration of this, a technology called supercritical fluid extraction of emulsions (SFEE) that uses the unique mass transfer mechanism and solvent power of a supercritical fluid (SCF) has been proposed to overcome the shortcomings of several conventional technologies such as solvent evaporation, extraction, and spray drying. This review article presents the main aspects of SFEE technology for the preparation of micro-/nanoparticles by focusing on its pharmaceutical applications, which have been organized and classified according to several types of drug delivery systems and active pharmaceutical ingredients. It was definitely confirmed that SFEE can be applied in a variety of drugs from water-soluble to poorly water-soluble. In addition, it has advantages such as low organic solvent residual, high EE, desirable release control, better particle size control, and agglomeration prevention through efficient and fast solvent removal compared to conventional micro-/nanoparticle technologies. Therefore, this review will be a good resource for determining the applicability of SFEE to obtain better pharmaceutical quality when researchers in related fields want to select a suitable manufacturing process for preparing desired micro-/nanoparticle drug delivery systems containing their active material. [ABSTRACT FROM AUTHOR]

This article reviews the use of fluids under supercritical conditions in processes related to the modern and innovative polymer industry. The most important processes using supercritical fluids are: extraction, particle formation, micronization, encapsulation, impregnation, polymerization and foaming. This review article briefly describes and characterizes the individual processes, with a focus on extraction, micronization, particle formation and encapsulation. The methods mentioned focus on modifications in the scope of conducting processes in a more ecological manner and showing higher quality efficiency. Nowadays, due to the growing trend of ecological solutions in the chemical industry, we see more and more advanced technological solutions. Less toxic fluids under supercritical conditions can be used as an ecological alternative to organic solvents widely used in the polymer industry. The use of supercritical conditions to conduct these processes creates new opportunities for obtaining materials and products with specialized applications, in particular in the medical, pharmacological, cosmetic and food industries, based on substances of natural sources. The considerations contained in this article are intended to increase the awareness of the need to change the existing techniques. In particular, the importance of using supercritical fluids in more industrial methods and for the development of already known processes, as well as creating new solutions with their use, should be emphasized. [ABSTRACT FROM AUTHOR]

In recent years, the demand for nutritive, functional and healthy foods has increased. This trend has induced the food industry to investigate novel technologies able to produce ingredients with enhanced functional and physicochemical properties. Among these technologies, one of the most promising is the encapsulation based on supercritical fluids. Thanks to the inherent absence of organic solvent, the low temperature of the process to reach a supercritical state and the capacity to dissolve lipid soluble bioactives, the encapsulation with supercritical carbon dioxide represents a green technology to produce several functional ingredients, with enhanced stability, high load and tailored protection from environmental factors. Furthermore, from the fine-tuning of the process parameters like temperature, pressure and flow rate, the resulting functional ingredient can be easily designed to tailor the controlled release of the bioactive, or to reach specific levels of taste, odor and color. Accordingly, the aim of the present review is to summarize the state of the art of the techniques based on supercritical carbon dioxide for the encapsulation of bioactive compounds of food interest. Pros and cons of such techniques will be highlighted, giving emphasis to their innovative aspects that could be of interest to the food industry. [ABSTRACT FROM AUTHOR]

Bacterial resistance to antibiotics is one of the biggest problems in the modern world. The prevention of bacterial spreading from hospitals to the community and vice versa is an issue we have to deal with. This review presents a vast potential of contemporary high-pressure techniques in the design of materials with antimicrobial activity. Scientists from all over the world came up with ideas on how to exploit extraordinary properties of supercritical fluids in the production of advantageous materials in an environmentally friendly way. The review summarizes reported methods and results. [ABSTRACT FROM AUTHOR]

Cellulose acetate (CA) is a very versatile biocompatible polymer used in various industrial sectors. Therefore, depending on the application, different morphologies are required. Different processes at industrial scale are commonly employed to obtain CA micro or nanoparticles (discontinuous structures) or CA membranes (continuous structures with discontinuities). In this work, two supercritical carbon dioxide (scCO2) based techniques, such as the semi-continuous supercritical antisolvent process (SAS) and the supercritical fluid phase inversion process, in which scCO2 plays the role of antisolvent, were employed. Varying the kind of organic solvent used to prepare the polymeric solution, the polymer concentration, and operating pressure and temperature, it was possible to tune the characteristics of the obtained material. In particular, using acetone as the organic solvent, filaments constituted by nanoparticles, expanded microparticles, nanoparticles with a mean diameter lower than 80 nm, and microporous membranes were obtained, varying the operating conditions. The attainment of spherical micron-sized particles was instead achieved using a mixture of acetone and DMSO as the organic solvent. Therefore, the versatility of the supercritical carbon dioxide-based techniques has been confirmed, and it was possible to obtain, using a single experimental plant, various morphologies of cellulose acetate (with controllable particles' or pores' diameters) by varying the operating conditions. [ABSTRACT FROM AUTHOR]

Micro- and nano-carrier formulations have been developed as drug delivery systems for active pharmaceutical ingredients (APIs) that suffer from poor physico-chemical, pharmacokinetic, and pharmacodynamic properties. Encapsulating the APIs in such systems can help improve their stability by protecting them from harsh conditions such as light, oxygen, temperature, pH, enzymes, and others. Consequently, the API's dissolution rate and bioavailability are tremendously improved. Conventional techniques used in the production of these drug carrier formulations have several drawbacks, including thermal and chemical stability of the APIs, excessive use of organic solvents, high residual solvent levels, difficult particle size control and distributions, drug loading-related challenges, and time and energy consumption. This review illustrates how supercritical fluid (SCF) technologies can be superior in controlling the morphology of API particles and in the production of drug carriers due to SCF's non-toxic, inert, economical, and environmentally friendly properties. The SCF's advantages, benefits, and various preparation methods are discussed. Drug carrier formulations discussed in this review include microparticles, nanoparticles, polymeric membranes, aerogels, microporous foams, solid lipid nanoparticles, and liposomes. [ABSTRACT FROM AUTHOR]