Microwaves in Soil Remediation from VOC’s. 1. Heat and Mass Transfer Aspects.

A novel technique presented performs in situ remediation of soils contaminated by volatile organic compounds (VOCs) based on the use of electromagnetic fields for heating operations. Attention is focused on heat and mass transfer occurring in porousmoisturized media like a soil matrix. The microwave induced steam distillation process is investigated. Measurements are reported of temperature, humidity, residual contaminant concentration, and permittivity during the process. The crucial role is elucidated that the changes of the dielectrical properties of the soil matrix play on the electromagnetic field propagation. A mathematical model of the remediation process relating all the parameters above is proposed and validated. doi: 10.1002/aic.69049072

Intensifying the microencapsulation process: Ultrasonic atomization as an innovative approach

In this review, new approaches to the microencapsulation processes, widely used in the manufacturing of pharmaceutical products, are discussed focusing the attention on the emerging ultrasonic atomization technique. Fundamentals and novel aspects are presented, and advantages of ultrasonic atomization in terms of intensification and low energy requests are emphasized

Single-Pot Semicontinuous Bench Scale Apparatus To Produce Microparticles

This work presents both the design of a novel process to produce microparticles with a shell−core structure and a bench scale apparatus purposely realized. The developed process was designed to respond to mandatory needs of process intensification. It involved the coupling of two emergent technologies: atomization assisted by ultrasonic energy and microwave heating. The former was used to atomize polymeric solutions; the latter was applied to stabilize the produced droplets by drying. Both operations were performed in the same vessel with the aim to have a single-pot process chamber and were carried out by a semicontinuous procedure. Basic design criteria and advantages of the ultrasonic−microwave coupled operations in the realized apparatus are presented and discussed. Results of testing and of operating runs to produce shell−core microparticles are also reported, emphasizing the main features of the produced particles

In vitro dissolution of pH sensitive microparticles for colon-specific drug delivery

Objective: The objective of this work is to prepare oral dosage systems based on enteric materials in order to verify their possible use as Colon-Specific Drug Delivery Systems (CSDDSs). Methodology: In particular, three different copolymers of methyl-methacrylate (MMA) - acrylic acid (AA) are synthesized with increasing percentage of MMA (from 70% to 73%) and they are used to produce microparticles by the double-emulsion solvent evaporation method. The microparticles, loaded using theophylline as model drug, are then tested for drug release under varying pH to reproduce what happens in the human GI tract. Results: All the investigated systems have shown an effective pH sensitiveness: they show a good gastro-resistance, releasing the model drug only at higher pH, small intestine or colon, depending on the kind of used copolymer. Conclusion: The results confirm the usefulness of both the materials and the methods proposed in this study for colon-specific delivery applications

Microonde e prodotti agro-alimentari

I trattamenti assistiti da microonde dei prodotti agro-alimentari, possono costituire un valido strumento per migliorare le performance delle operazioni unitarie tradizionali tipiche dell’industria alimentare, per ottenere cibi con un elevato profilo nutrizionale oltre che sanitizzati, edibili e conservabili

Pharmaceutical Applications of Biocompatible Polymer Blends ontaining Sodium Alginate

Biocompatible polymer blends, such as alginate blends, have a widespread use in pharmaceutical and medical applications due to their specific features, such as biodegradation, adhesiveness, and thermo- and pH sensitivity and that can be obtained from the mixture composition. In this work, the use of alginate blends was tested in a novel production methodology of therapeutic dosage forms based on polymeric chain reticulation phenomena induced by exposure to bivalent ions. Two kinds of sodium alginate were used to obtain gel films (structured films) in blends with Pluronic F127®. The blends were considered for applications in gel paving of drug-eluting stents. Sodium alginate was also used in shell–core particle production (structured particles) to obtain shell-barrier reducing drug release in the preparative steps (see wash operations). Both structures, films and particles, were obtained using Cu2+ and Ca2+ ions, respectively. Film/shell barrier properties were tested in dissolution experiments using vitamin B12 as an active molecule model. Experimental work demonstrated that the alginate composition is a crucial point in defining reticulated structures

Microencapsulation effectiveness of small active molecules in biopolymer by ultrasonic atomization technique

A method to produce biopolymeric (alginate) microparticles by ultrasonic assisted atomization, previously developed, has been applied to the production of microparticles loaded with a small active molecule (theophylline). Fine loaded alginate droplets have been cross-linked with divalent ions to produce microparticles. Once produced, the particles have been separated by centrifugation or filtration and then they have been dried. Drug release has been evaluated by dissolution tests, dissolving the dried particles in acidic solution at pH 1 for a given time and then at pH 7 to simulate the stomach and intestinal environment, respectively. The encapsulation efficiency and the drug loading have been investigated and the operating conditions have been changed to clarify the role of the transport phenomena on the overall process. To increase the drug loading, shorter separation time and better network’s structure were identified as the key operating parameters to allow the process to gain interest from a practical point of view

Intensification of biopolymeric microparticles production by ultrasonic assisted atomization

In this work ultrasonic atomization process is applied to produce biopolymer microparticles with potential applications in pharmaceutical and nutraceutical fields. Natural polymer (alginate)/water solution is atomized by ultrasonic assisted process and the droplets spray is reticulated using a solution of copper sulfate, where the Cu2+ ions cause the formation of a network structure (hard porous gel). Several operating parameters (solution concentration, flow rate, atomization power) are changed to study their effects on the produced microparticles. Literature correlations able to predict the features of the droplets as functions of process parameters are optimized using a statistical approach. Furthermore, the energy requirement for the drops production is compared with the energy required by traditional techniques to evaluate the intensification effect of the ultrasonic on the atomization process. doi:10.1016/j.cep.2009.08.00

Swelling of cellulose derivative (HPMC) matrix systems for drug delivery

The water swellable hydrogels are commonly used in the production of solid pharmaceutical dosage systems for oral administration (matrices). Their use allows to obtain the controlled drug release. The key role is played by the transport phenomena which take place: water up-take, gel swelling and erosion, increase in diffusivity due to hydration. Thus, knowledge of these phenomena is fundamental in designing and realizing the pharmaceutical systems. In this work, tablets made of pure hydrogel, HydroxyPropyl-MethylCellulose (HPMC), were produced and immersed in a thermostatic bath filled with stirred distilled water (37 °C). The water up-take was allowed only by radial direction (from the lateral surface) by confining the tablet between two glass slides. Two distinct methods, an optical technique already described in a previous work, and a gravimetric procedure described here, were applied to measure the water concentration profiles along the radial direction in the tablets. The data obtained were used both to clarify the nature of the transport phenomena involved, and to perform a better tuning of a mathematical model previously proposed. doi:10.1016/j.carbpol.2009.05.00