There have been major advances in the design and fabrication of structured delivery systems for the encapsulation of nutraceutical and functional food components. A wide variety of delivery systems is now available, each with its own advantages and disadvantages for particular applications. This review begins by discussing some of the major nutraceutical and functional food components that need to be delivered and highlights the main limitations to their current utilization within the food industry. It then discusses the principles underpinning the rational design of structured delivery systems: the structural characteristics of the building blocks; the nature of the forces holding these building blocks together; and, the different ways of assembling these building blocks into structured delivery systems. Finally, we review the major types of structured delivery systems that are currently available to food scientists: lipid-based (simple, multiple, multilayer, and solid lipid particle emulsions); surfactant-based (simple micelles, mixed micelles, vesicles, and microemulsions) and biopolymer-based (soluble complexes, coacervates, hydrogel droplets, and particles). For each type of delivery system we describe its preparation, properties, advantages, and limitations.

Structural design principles for delivery of bioactive components in nutraceuticals and functional foods.

Interest in hot-melt extrusion techniques for pharmaceutical applications is growing rapidly with well over 100 papers published in the pharmaceutical scientific literature in the last 12 years. Hot-melt extrusion (HME) has been a widely applied technique in the plastics industry and has been demonstrated recently to be a viable method to prepare several types of dosage forms and drug delivery systems. Hot-melt extruded dosage forms are complex mixtures of active medicaments, functional excipients, and processing aids. HME also offers several advantages over traditional pharmaceutical processing techniques including the absence of solvents, few processing steps, continuous operation, and the possibility of the formation of solid dispersions and improved bioavailability. This article, Part I, reviews the pharmaceutical applications of hot-melt extrusion, including equipment, principles of operation, and process technology. The raw materials processed using this technique are also detailed and the physicochemical properties of the resultant dosage forms are described. Part II of this review will focus on various applications of HME in drug delivery such as granules, pellets, immediate and modified release tablets, transmucosal and transdermal systems, and implants.

Pharmaceutical Applications of Hot-Melt Extrusion: Part I

The protection and controlled release of bioactive compounds at the right time and the right place can be implemented by encapsulation. Nanoencapsulation remains to be the one of the most promising technologies having the feasibility to entrap bioactive compounds. Nanoencapsulation of bioactive compounds has versatile advantages for targeted site-specific delivery and efficient absorption through cells. However, researches in the application of nanotechnology in the food industry have been very limited and there are only a few review articles that explored the nanoencapsulation technology. This review focuses on the various nanoencapsulation techniques such as emulsification, coacervation, inclusion, complexation nanoprecipitation, emulsification–solvent evaporation, and supercritical fluid for food ingredients. Drying techniques such as spray drying and freeze drying for stabilization of nanoparticles are also discussed. Current state of knowledge, limitations of these techniques, and recent trends are also discussed. Finally, safety and regulatory issues in the nanoencapsulation of bioactive compounds are also highlighted.

Nanoencapsulation Techniques for Food Bioactive Components: A Review

Ultrasound (US) has an ever-increasing role in the delivery of therapeutic agents including genetic material, proteins, and chemotherapeutic agents. Cavitating gas bodies such as microbubbles are the mediators through which the energy of relatively non-interactive pressure waves is concentrated to produce forces that permeabilize cell membranes and disrupt the vesicles that carry drugs. Thus the presence of microbubbles enormously enhances delivery of genetic material, proteins and smaller chemical agents. Delivery of genetic material is greatly enhanced by ultrasound in the presence of microbubbles. Attaching the DNA directly to the microbubbles or to gas-containing liposomes enhances gene uptake even further. US-enhanced gene delivery has been studied in various tissues including cardiac, vascular, skeletal muscle, tumor and even fetal tissue. US-enhanced delivery of proteins has found most application in transdermal delivery of insulin. Cavitation events reversibly disrupt the structure of the stratus corneum to allow transport of these large molecules. Other hormones and small proteins could also be delivered transdermally. Small chemotherapeutic molecules are delivered in research settings from micelles and liposomes exposed to ultrasound. Cavitation appears to play two roles: it disrupts the structure of the carrier vesicle and releases the drug; it also makes the cell membranes and capillaries more permeable to drugs. There remains a need to better understand the physics of cavitation of microbubbles and the impact that such cavitation has upon cells and drug-carrying vesicles.

/pdf/ultrasonic-drug-delivery-a-general-review-53bn9zfyxj.pdf

Ultrasonic Drug Delivery – A General Review

The application of nanotechnology to food, medical and pharmaceutical industries has received great attention from the scientific community. Driven by the increasing consumers’ demand for healthier and safer food products and the need for edible systems able to encapsulate, protect, and release functional compounds, researchers are currently focusing their efforts in nanotechnology to address issues relevant to food and nutrition. Nanoemulsion technology is particularly suited for the fabrication of encapsulating systems for functional compounds as it prevents their degradation and improves their bioavailability. This review focuses on nanoemulsions and provides an overview of the production methods, materials used (solvents, emulsifiers, and functional ingredients) and of the current analytical techniques that can be used for the identification and characterization of nanoemulsions. Finally, nanotechnological applications in foods currently marketed are reported.

/pdf/nanoemulsions-for-food-applications-development-and-41v8jd5knn.pdf

Nanoemulsions for Food Applications: Development and Characterization

In recent years, the use of nebulisers to generate aerosols has been greatly extended because of their numerous advantages. Two types of nebulisers are commonly used, each based on a different principle : - jet nebulisers, based on the Venturi effect to fragment liquid preparations into small droplets. - ultrasonic nebulisers, using the vibrations of a quartz to produce aerosol. The use of nebulisers lacks standardisation, which may account for certain inefficiency. First of all, we defined the parameters required to evaluate nebulisation efficiency. Although droplet size is a commonly used parameter, it is not sufficient to forecast efficiency. It must be associated with the quantity of drug nebulised and nebulisation time. Secondly, we listed factors influencing nebulisation efficiency.

Factors influencing nebulizing efficiency

The principle of an ultrasonic nebulizer is based on the vibrations of a piezoelectric crystal driven by an alternating electrical field. These periodic vibrations are characterized by their frequency, their amplitude, and their intensity, which corresponds to the energy transmitted per surface unit. When the vibration intensity is sufficient, cavitation occurs, and droplets are generated. Ventilation enables airflow to cross the nebulizer and to expel the aerosol droplets. For a given nebulizer, the vibration frequency of the piezoelectric crystal is fixed, often in the range 1–2.5 MHz. In most cases, an adjustment in vibration intensity is possible by modifying vibration amplitude. The ventilation level is adjustable. The vibrations may be transmitted through a coupling liquid—commonly water—to a nebulizer cup containing the solution to be aerosolized. In this work, we studied the influence of the technological parameters of ultrasonic nebulization on nebulization quality. Our study was carried out with...

Study of the Technological Parameters of Ultrasonic Nebulization

The aim of this study was to develop monodimensional, spherical particles of 400 µm by extrusion‐spheronization. An Alexanderwerk GA65 cylinder extruder with two counter‐rotating rollers associated with a Caleva model 15 spheronizer were used. The study was made with an auxiliary substance of fatty consistency and with amphiphilic properties: Gelucire 50/02. The plasticity of the mass can be deduced using a piston extruder. Pellet quality can be determined by particle‐size analysis and shape estimation by microscopy. Modifications to the cylinders and the extruder itself are required for feasibility studies of extruded materials of 400 µm. The horizontal plate of the spheronizer had to be adapted to take into account the small size of the extruded materials. For the chosen auxiliary substance, Gelucire 50/02, the formulation of the wet mass to be extruded and the conditions required to obtain this mass were defined. The results show the feasibility of 400 µm pellets with Gelucire 50/02. At least 90% of th...

Development of 400 µm Pellets by Extrusion‐Spheronization Application with Gelucire 50/02 to Produce a “Sprinkle” Form

The objective of this work was to develop a galenic form of activated charcoal appropriate for the needs of clinical toxicology. To preserve the adsorption capacity of charcoal, we developed an extemporaneous preparation of activated charcoal intended for clinical toxicology. To improve the wettability of activated charcoal, we used densification by wet granulation. The presence of a viscosity agent is necessary to ensure the homogeneity of the suspension and its adhesiveness on gastric mucous membrane. Five formulations with different viscosity agents were prepared, and their adsorption capacity, wettability, viscosity, and adhesiveness were studied.

P. Leterme

Papers

Factors influencing nebulizing efficiency

Study of the Technological Parameters of Ultrasonic Nebulization

Development of 400 µm Pellets by Extrusion‐Spheronization Application with Gelucire 50/02 to Produce a “Sprinkle” Form

Formulation of activated charcoal for per os administration to addicted subjects.