Chitosan composite microparticles: A promising gastroadhesive system for taxifolin.

Taxifolin possesses gastroprotective property but is characterized by low water solubility, is instabile in alkaline medium, and is degraded by the intestinal bacteria flora. The purpose of the work was therefore to produce a gastroadhesive formulation to prolong taxifolin residence time and release in the stomach. We first demonstrated that taxifolin is stable in simulated gastric fluid with or without pepsin and mucus, and is able to cross pig gastric mucus layer and stomach mucosa. Next, gastromucoadhesive microparticles composed of Syloid® AL-1 mesoporous silica, chitosan and HPMC were produced using spray-drying. Microparticles were characterized by a spherical shape and a mean volume-equivalent diameter around 12 µm. The optimized microparticles were able to release taxifolin and to adhere to pig stomach mucosa for 5 h.

Intercalation of the radical scavenger ferulic acid in hydrotalcite-like anionic clays.

Hydrotalcite is a biocompatible lamellar anionic clay formed by double hydroxide layers with a metal cation coordinating four OH groups. The different layers are held together by anionic hosts that can be replaced by a simple ion-exchange process. The synthetic Mg-Al-hydrotalcite was used to intercalate ferulic acid, a compound that shows antioxidant properties due to its free radical scavenger capacity. Analysis of the intercalated compound showed a good intercalation percentage (35.53%) accompanied by an increase of the interlayer space from 7.8A (chloride form) to 17.1A due to the presence of the ferulate. The intercalation product was stable in water, did not show any significant degradation after UV-irradiation, had a higher capacity of UV absorption in comparison to both the pure ferulic acid and ferulic acid-hydrotalcite chloride physical mixture. The intercalated compound was formulated in a siliconic cream and the ferulate in vitro release profiles determined.

Nanoparticles in biomedicine: new insights from plant viruses.

In recent years there has been an outburst of interest regarding the employment of nanoparticles for biomedical applications. Among the different types, such as metallic, organic, biological and hybrid systems, virus based nanoparticles have become a popular field of research. Viruses are able to form organized structures by molecular self assembly of repetitive building blocks, which implies non covalent interactions of protein monomers to form the quaternary structure of viral capsids. Plant virus based systems, in particular, are among the most advanced and exploited for their potential use as bioinspired structured nanomaterials and nanovectors. Plant viruses have a size particularly suitable for nanoscale applications and can offer several advantages. In fact, they are structurally uniform, robust, biodegradable and easy to produce. Moreover, many are the examples regarding functionalization of plant virus based nanoparticles by means of modification of their external surface and by loading cargo molecules into their internal cavity. This plasticity in terms of nanoparticles engineering is the ground on which multivalency, payload containment and targeted delivery can be fully exploited. This review aims primarily to summarize the most important plant virus based nanoparticles systems through their recent applications in biomedicine, such as epitope display for vaccine development and targeted delivery for diagnosis or therapy. In addition, their production in the most commonly used plant propagation and expression systems will be also reviewed.

Developing and advancing dry powder inhalation towards enhanced therapeutics.

Enhanced therapeutics are drug products derived from existing generic drugs that provide additional benefits to the patients and the healthcare system. Enhanced therapeutics are considered to be an important and relatively low risk source of innovation. Pulmonary drug delivery is the major delivery route to treat chronic respiratory diseases and has been proven as a potential delivery route for complex drugs that cannot be delivered orally. Development of dry powder inhalation systems targets the delivery of fine drug particles to the deep lung surface by a combination of drug formulation, primary packaging and a device, whereby each contributes to the overall performance. Various methodologies for the non-clinical and clinical performance testing of orally inhaled products have been proposed and applied with variable success. Regulatory pathways have been developed and applied since. Considerable efforts have been made during the past decade to understand and optimize pulmonary drug delivery including their efficient commercial manufacturing. Pulmonary drug delivery remains an area of future innovation in the effective treatment of pulmonary diseases as well as the systemic delivery of systemically active complex drugs.