Reactive Deep Eutectic Solvent for an Eco-Friendly Synthesis of Cellulose Carbamate.

The limited solubility of natural cellulose in water and common organic solvents hinders its diverse applications, despite being one of the most abundant and easily accessible biopolymers on Earth. Chemical derivatization, such as cellulose carbamate (CC), offers a pathway to enhance both solubility and industrial processability. In this study, CC was synthesized by exploiting a novel type IV deep eutectic solvent (DES) composed of erbium trichloride and urea. This DES was shown to be not only an environmentally friendly reaction medium/catalyst but also actively participated in the synthetic process as a reagent. The resultant cellulose carbamate samples were characterized through FT-IR and elemental analysis. A nitrogen content value of 1.59% was afforded determining a degree of substitution corresponding to a value of 0.19. One of the key scientific advancements lies in the preparation of cellulose carbamate using a straightforward and cost-effective method. This approach utilizes non-toxic compounds, aligning with the principles of green chemistry and contributing to sustainable development in cellulose derivative production.

Reactive deep eutectic solvents for EDC-mediated amide synthesis.

The sustainability of amide bond formation is an ever-present topic in the pharmaceutical industry, as it represents the common motif in many clinically approved drugs. Despite many procedures for accomplishing eco-friendly amide synthesis having been developed, this transformation still remains a contemporary challenge. Herein, we report a greener approach for amide synthesis by using Reactive Deep Eutectic Solvents (RDESs) acting as both the reaction medium and reactants. The procedure not only avoids the use of hazardous solvents but also provides operationally simple product recovery with high purity and efficiency, without chromatographic purification. This approach was efficiently applied to the synthesis of a key intermediate in the production of an active pharmaceutical ingredient like atenolol. The green metrics of the gram-scale procedure were compared to the conventional industrial strategy showing an advancement in the greening of amide synthesis.

Green Chemistry Principles for Nano- and Micro-Sized Hydrogel Synthesis.

The growing demand for drug carriers and green-technology-based tissue engineering materials has enabled the fabrication of different types of micro- and nano-assemblies. Hydrogels are a type of material that have been extensively investigated in recent decades. Their physical and chemical properties, such as hydrophilicity, resemblance to living systems, swelling ability and modifiability, make them suitable to be exploited for many pharmaceutical and bioengineering applications. This review deals with a brief account of green-manufactured hydrogels, their characteristics, preparations, importance in the field of green biomedical technology and their future perspectives. Only hydrogels based on biopolymers, and primarily on polysaccharides, are considered. Particular attention is given to the processes of extracting such biopolymers from natural sources and the various emerging problems for their processing, such as solubility. Hydrogels are catalogued according to the main biopolymer on which they are based and, for each type, the chemical reactions and the processes that enable their assembly are identified. The economic and environmental sustainability of these processes are commented on. The possibility of large-scale processing in the production of the investigated hydrogels are framed in the context of an economy aimed at waste reduction and resource recycling.

Multifunctional Microspheres Based on D-Mannose and Resveratrol for Ciprofloxacin Release.

This article describes the preparation, characterization, and performance evaluation of functional microspheres useful for the release of ciprofloxacin. The particles were obtained using D-mannose, a natural aldohexose sugar, and resveratrol, a powerful antioxidant. In particular, the above compounds were initially converted into D-mannose carboxylate and resveratrol methacrylate and, therefore, subjected to an esterification reaction. The resulting product was used for the preparation of the microspheres which were characterized by light scattering, FT-IR spectrophotometry and scanning electron microscopy (SEM). Subsequently, their degree of bloating was evaluated at pH 1.2 to simulate the pH of the stomach, at pH 6.8 and pH 7.4 to mimic the intestinal environment. The antibiotic ciprofloxacin was then loaded into the microspheres, with an encapsulation efficiency of 100%. The cumulative amount of drug released was 55% at pH 6.8 and 99% at pH 7.4. The tests conducted to evaluate the antibacterial activity demonstrated the ability of the microspheres obtained to inhibit the growth of Escherichia coli. The antioxidant efficacy, due to the presence of resveratrol in their structure, was confirmed using rat liver microsomal membranes. The results obtained have highlighted how the microspheres based on D-mannose and resveratrol can be considered promising multifunctional vectors useful in the treatment of intestinal and urinary infections.

Deep Eutectic Solvents for Improving the Solubilization and Delivery of Dapsone.

Owing to a growing awareness toward environmental impact, the use of safer and eco-friendly solvents like deep eutectic solvents (DESs), has recently undergone important growth in the pharmaceutical field, with regard to their application as non-aqueous liquid administration vehicles, since they do not carry the same risks of toxicity and handling as traditional organic solvents. Major attention has been given to the development of advantageous transdermal drug delivery systems, because of their ease of use and better acceptability. Here, we report the use of two different DESs, based on choline chloride, used as hydrogen bond acceptor (HBA), and ascorbic acid or propylene glycol, used as hydrogen bond donors (HBDs), able to enhance the solubility and the topical delivery of dapsone, representing a class IV drug. The interactions between the DESs' components and the drug were studied by performing DSC, FT-IR, and NMR analysis of the eutectic systems and the pure drug, confirming the establishment of H-bonds between the drug and the DESs' components. Diffusion and permeability studies, carried out in a Franz cell, showed an increase in permeability, highlighting the great potential of DESs as dissolution and permeation enhancers in the development of novel and more effective drug delivery systems in topical administration.

Green solvents for the formation of amide linkages.

The formation of the amide bond is among the most commonly performed transformations in the pharmaceutical industry and the wider chemical industry. The current methods for its installation in organic compounds frequently rely on the use of large amounts of organic solvents, mainly N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and dichloromethane (DCM), which have been associated with adverse environmental and health concerns over the last decades. This fact led academia and industry to make significant efforts toward the development of synthetic routes with the aim to avoid, reduce or replace the use of hazardous solvents. The present review fits into this framework and discusses the literature existing over the past ten years on strategies for reducing and replacing hazardous solvents, focusing on the use of biobased and neoteric solvents, such as ionic liquids and deep eutectic solvents (ILs and DESs, respectively), and on the reaction media that proved to be greener alternatives for amide bond formation.

Valorization of Tomato Waste as a Source of Carotenoids.

Fast-accumulating scientific evidence from many studies has revealed that fruits and vegetables are the main source of bioactive compounds; in most cases, wastes and byproducts generated by the food processing industry present similar or a higher content of antioxidant compounds. In recent years, the ever-growing amount of agricultural and food wastes has raised serious concerns from an environmental point of view. Therefore, there is an increasing interest in finding new ways for their processing toward safely upgrading these wastes for recovering high-value-added products with a sustainable approach. Among food waste, the abundance of bioactive compounds in byproducts derived from tomato suggests possibility of utilizing them as a low-cost source of antioxidants as functional ingredients. This contribution gives an overview of latest studies on the extraction methods of carotenoids from tomato waste, along with an evaluation of their antioxidant activity, as well as their industrial applications.