Supercritical Carbon Dioxide as a Green Alternative to Achieve Drug Complexation with Cyclodextrins

Cyclodextrins are widely used in pharmaceutics to enhance the bioavailability of many drugs. Conventional drug/cyclodextrin complexation techniques suffer from many drawbacks, such as a high residual content of toxic solvents in the formulations, the degradation of heat labile drugs and the difficulty in controlling the size and morphology of the product particles. These can be overcome by supercritical fluid technology thanks to the outstanding properties of supercritical CO2 (scCO2) such as its mild critical point, its tunable solvent power, and the absence of solvent residue after depressurization. In this work the use of scCO2 as an unconventional medium to achieve the complexation with native and substituted cyclodextrins of over 50 drugs, which belong to different classes, are reviewed. This can be achieved with different approaches such as the “supercritical solvent impregnation” and “particle-formation” techniques. The different techniques are discussed to point out how they affect the complexation mechanism and efficiency, the physical state of the drug as well as the particle size distribution and morphology, which finally condition the release kinetics and drug bioavailability. When applicable, the results obtained for the same drug with various cyclodextrins, or different complexation techniques are compared with those obtained with conventional approaches.

Classification and Production of Polymeric Foams among the Systems for Wound Treatment

This work represents an overview on types of wounds according to their definition, classification and dressing treatments. Natural and synthetic polymeric wound dressings types have been analyzed, providing a historical overview, from ancient to modern times. Currently, there is a wide choice of materials for the treatment of wounds, such as hydrocolloids, polyurethane and alginate patches, wafers, hydrogels and semi-permeable film dressings. These systems are often loaded with drugs such as antibiotics for the simultaneous delivery of drugs to prevent or cure infections caused by the exposition of blood vessel to open air. Among the presented techniques, a focus on foams has been provided, describing the most diffused branded products and their chemical, physical, biological and mechanical properties. Conventional and high-pressure methods for the production of foams for wound dressing are also analyzed in this work, with a proposed comparison in terms of process steps, efficiency and removal of solvent residue. Case studies, in vivo tests and models have been reported to identify the real applications of the produced foams.

Experimental study on lowering oleic acid value and peroxide value of camellia sinensis by scraping film molecular distillation

Camellia oil is a kind of natural product with high added value. In the process of production, processing, and transportation, acidic substances and peroxides that reduce the quality of oil are produced. In this paper, it was refined by scraping membrane molecular distillation device. The factors affecting the molecular distillation results were analyzed and studied through a single factor experiment and orthogonal experiment. On the surface of the experiment, the optimal process parameters were as follows: the temperature was 190℃, the pressure was 1 Pa, the scraping speed was 300r/min, and the feed amount was 900g/h. Under this condition, the acid value in camellia oil decreased from 2.67mgKOH/g to 0.19mgKOH/g, and the free fatty acid removal rate was 92.88%. The peroxide value decreased from 16.78mmol/kg to 1.03mmol/kg, and the peroxide removal rate was 93.86%. The experimental results showed that the surface of the scraping membrane molecular distillation equipment could meet the national standard of acid value and peroxide value under the appropriate technological parameters, and there was no solvent residue, which was a safe physical purification process.

Liposomes: From Bangham to Supercritical Fluids

Liposomes are spherical vesicles made up of an aqueous core surrounded by phospholipids. These delivery systems (DS) are largely employed as drug carriers in several industrial fields, such as pharmaceutical and nutraceutical fields. The aim of this short review is to provide a fast overview on the main fundamentals of liposomes, thought as a compact guide for researchers and students that want to approach this topic for the first time. The mini-review will focus on the definitions, production methods and characterization protocols of the liposomes produced, making a critical comparison of the main conventional and supercritical based manufacturing methods available. The literature was analyzed deeply from the first works by Dr. Bangham in 1965 to the most recent supercritical fluid applications. The advantages and disadvantages of conventional and high-pressure processes will be described in terms of solvent elimination, production at the nanometric (50–300 nm) and micrometric level (1–100 μm) and encapsulation efficiency (20–90%). The first proposed methods were characterized by a low encapsulation efficiency (20–40%), resulting in drug loss, a high solvent residue and high operating cost. The repeatability of conventional processes was also low, due to the prevalent batch mode. Supercritical-assisted methods were developed in semi-continuous layouts, resulting in an easy process scale-up, better control of liposome dimensions (polydispersity index, PDI) and also higher encapsulation efficiencies (up to 90%).

A Review on Production of Exopolysaccharide and Biofilm in Probiotics Like Lactobacilli and Methods of Analysis

Synthesis of exopolysaccharides (EPSs) by lactic acid bacteria is well known and the EPS produced by Lactobacillus has been highly regarded in recent years because of its unique physical and chemical application in the food and pharmaceutical industry. One of the capabilities of probiotics is the use of EPS to form a biofilm produced in tense environments. In this paper after a short description about EPS, the reason for production in bacterial cells, and its biosynthesis pathways; the capability of Lactobacilli for EPS and biofilm formation are reviewed. The chemical composition of EPS, its role in the bacterial life cycle as well as applications for humankind have been studied. Then the important components in biofilm formation are described and variable influencing on biofilm formation (surface, bacterial cell surface, contact time and environmental characteristics) are reviewed. The relationship between EPS and extracellular polymeric precursors as well as the relationship between biofilm formation and EPS production are mentioned. Finally, methods for quantification of carbohydrate (enzymatic, physical, chemical methods), biofilm formation and EPS extraction (Tallon and Bajpai methods) are reviewed and advantages of methods are compared. EPSs produced by probiotics is important due to the application as a thickening agent, emulsifier, heavy metal eliminator, and drug delivery carrier. Also, it has been considered for its anti-cancer, anti-viral, and cholesterol-lowering properties. So forming biofilm by some probiotics in simple and mixed culture are discussed, the relationship between EPS and biofilm production are discussed. When probiotics produce biofilm, they can be more tolerated in the processing of food production and in the gastrointestinal tract. So the efficacy of probiotic transfer may increase by a self-protection potency without any required encapsulation processing, solvent residue, time and energy consumption, etc. Also, identification and measurement methods are reviewed and compared.

SPECIFIC AND NON-SPECIFIC PARAMETERS BASED ON SIMPLICIA AND ETHYL ACETATE FRACTIONS OF STAR FRUIT LEAVES (AVERRHOA CARAMBOLA L.)

Objective: Star fruit (Averrhoa carambola L.) is a plant with numerous benefits, including anti-skin inflammation properties. The aim of the presentstudy was to evaluate simplicia and ethyl acetate fractions of star fruit leaves collected from three regions in Indonesia, including Depok, Subang, andSukabumi, and to characterize specific and non-specific parameters.Methods: Extraction was performed through maceration. Next, liquid partitioning was performed to obtain ethyl acetate fractions. Chromatogramsfor simplicia and ethyl acetate fractions for samples from three regions were obtained using chloroform: methanol:water (8:2:0.5) with apigenin asthe standard.Results: The yield of the ethyl acetate fraction from the star fruit leaves was 4.2–6.2%. Water content, total ash content, and acid-soluble ash contentswere 4.79%, 1.55%, and 0.064%, respectively, and total flavonoid levels were 14.63–22.14 mg QE/g of a fraction. The water-soluble and ethanol-solubleextracts were 14.32% and 9.69%, respectively, and total flavonoid contents were 0.12–0.18 mg QE/g simplicia. In addition, drying losses, ash content,and acid-soluble ash content were 9.70%, 7.14%, and 0.31%, respectively. The results of solvent residues and heavy metal contaminant (Hg, Pb, Cd,and As) tests indicated that the ethyl acetate fraction did not contain solvent residue or heavy metal contamination.Conclusion: The specific and non-specific parameters based on simplicia and ethyl acetate fractions from star fruit leaves meet the requirement.

Biolarvicidal Potentials of the Methanolic-Leaf-Extracts of Selected Tropical Plant Species

Solvent residue such as hexane in foodstuff, especially edible oil could be considered as the undesirable substances when exceeds maximum residue limit (MRL). The aim of this study is to determine the hexane content in various brands of edible oils. Totally forty samples (23 brands) of different types of vegetable oils including frying oils (n=14), blended oils (n=13), sunflower oils (n=6), corn oils (n=5) and canola oils (n=2) from Iran´s market were analyzed for hexane content using solid phase microextraction gas chromatography equipped with a flame-ionization detector (SPME)-GC-(FID). The hexane residue was detected in thirty-six out of forty examined samples, ranged from lower than LOD to 42.6 µg/kg. However, in all of them hexane content were below the MRL of 1 mg/kg which set by the European Union.

Optimization of NMP Extraction in 1, 3-Butadiene Production Line

N-methylpyrrolidone is a powerful solvent for variety of chemical processes due to its vast chemical properties. It has been used in manufacturing processes of polymers, detergents, pharmaceuticals rubber and many more chemical substances. However, it creates large amount of residue in some of these processes which has to be dealt with. Many well known methods such as BASF in rubber producing units have tried to regenerate the solvent at the end of each run, however, there is still discarding of large amount of residue containing NMP, which over time, could cause environmental concerns. In this study, we have tried to optimize regeneration of the NMP extraction from butadiene production. It is shown that at higher temperatures NMP is separated from the residue with close to 90% efficiency, and the solvent residue proved to be the most effective with a 6: 1 ratio.

Evaluation of Hexane Content in Edible Vegetable Oils Consumed in Iran

Solvent residue such as hexane in foodstuff, especially edible oil could be considered as the undesirable substances when exceeds maximum residue limit (MRL). The aim of this study is to determine the hexane content in various brands of edible oils. Totally forty samples (23 brands) of different types of vegetable oils including frying oils (n=14), blended oils (n=13), sunflower oils (n=6), corn oils (n=5) and canola oils (n=2) from Iran´s market were analyzed for hexane content using solid phase microextraction gas chromatography equipped with a flame-ionization detector (SPME)-GC-(FID). The hexane residue was detected in thirty-six out of forty examined samples, ranged from lower than LOD to 42.6 µg/kg. However, in all of them hexane content were below the MRL of 1 mg/kg which set by the European Union.