Francesco Izzo

Rheology-sensitive response of zeolite-supported anti-inflammatory drug systems

Drug release from inorganic supports is a challenge for the scientific community for various reasons, related to the low costs of the systems and the possibility of easily regulating the drug release. In the present work, surface-modified zeolite particles are used as carriers for non steroidal antiflammatory drugs (NSAIDs). The release of the drug has been studied in a solution that simulates the intestinal fluid as well as in a gel-like system, based on a surfactant and a binding salt. In the solution case, the quantity of drug released has been tracked via spectrophotometric assay. Release in the gel has been monitored by rheological methods. The molecular conformation of the NSAIDs is fundamental for the interaction with the zeolite surface, whose modified surface has a strong binding energy. It has been proven that the main mechanism for the drug release is anion exchange. It has been found that the NSAIDs, used in their sodic form, can act as binding salts by themselves in the gel-like system, thus changing the viscoelastic response of the overall solution. Drug release kinetics in the solution compare quantitatively well with the released drug in the gel-like fluid, as measured by rheometry.

The characterization of natural gemstones using non-invasive FT-IR spectroscopy: New data on tourmalines

Fourteen samples of tourmaline from the Real Museo Mineralogico of Federico II University (Naples) have been characterized through multi-methodological investigations (EMPA-WDS, SEM-EDS, LA-ICP-MS, and FT-IR spectroscopy). The samples show different size, morphology and color, and are often associated with other minerals. Data on major and minor elements allowed to identify and classify tourmalines as follows: elbaites, tsilaisite, schorl, dravites, uvites and rossmanite. Non-invasive, non-destructive FT-IR and in-situ analyses were carried out on the same samples to validate this chemically-based identification and classification. The results of this research show that a complete characterization of this mineral species, usually time-consuming and expensive, can be successfully achieved through non-destructive FT-IR technique, thus representing a reliable tool for a fast classification extremely useful to plan further analytical strategies, as well as to support gemological appraisals.

The combined use of steam-treated bentonites and natural zeolites in the oenological refining process

Abstract Industrial minerals, particularly bentonites, have long been used in treatments to improve the stability and shelf life of white wines. We evaluated a new combination of rocks and minerals, including steam-treated bentonites and natural zeolites (chabazite and phillipsite), to greatly reduce the risk of protein and tartaric instability of wines. Detailed mineralogical, chemical and electrokinetic studies of these materials were conducted using powder X-ray diffraction (PXRD), X-ray fluorescence (XRF), microporosimetry, BET surface-area analysis and zeta-potential measurements. Several model wine solutions containing Bovine Serum Albumin (BSA) were prepared to evaluate the oenological performance of the rock/mineral combinations. UV-VIS spectrophotometry and ion chromatography were used to evaluate the degree of wine stabilization from the protein and tartaric point of view. The experimental results showed that steam treatment modifies both the microporosity and external surface area of the bentonite. These changes in surface area, along with creation of hydrophobic surfaces, significantly modified the behaviour of the steam-treated bentonites, requiring an increase in the amount of material necessary to bring the protein content to required levels. An important benefit derived from the use of steam-treated bentonites is that the pre-mixing with water before addition to wine is not necessary, as the material is readily dispersed. Finally, the addition of natural zeolites effectively decreased the potassium content, thereby improving the tartaric stability of white wines. In addition, this procedure results in minimal waste, as the bentonite-zeolite mixture can be reused as soil amendments in agriculture.

Non-invasive FTIR spectroscopy: new preliminary data for the identification of mineralogical phases forming Cultural Heritage materials

This paper focuses on the application of external reflection Fourier Transform Infrared spectroscopy for the classification of some minerals commonly used as gemstones and mineral collection: quartz (colourless, tourmalinated and smoky varieties), calcite and aragonite.The results highlight the differences between reflectance and absorbance spectra, allowing a faster, cheaper and non-destructive approach for the identification of monocrystalline minerals.

Surface-modified phillipsite-rich tuff from the Campania region (southern Italy) as a promising drug carrier: An ibuprofen sodium salt trial

Abstract The encapsulation and delivery of drugs often involves the use of expensive microporous materials, and we have investigated the potential for natural zeolites from the widespread volcanic formations of southern Italy as alternatives to these carriers. Surface-modified natural zeolites (SMNZs) with diverse micellar structures (patchy and complete bilayers) were obtained by using different cationic surfactants [cetylpyridinium chloride (CP-Cl), benzalkonium chloride (BC-Cl), hexadecyltrimethylammonium chloride (HDTMA-Cl), and bromide (HDTMA-Br) with phillipsite-rich tuff from the Campania region (southern Italy)]. Loading and release kinetics tests of sodium ibuprofen (IBU) were carried out with organo-phillipsite composites using Fourier transform infrared spectroscopy (FTIR) and thermal analysis coupled with evolved gas analysis (EGA). Results from these tests were mathematically modeled to evaluate IBU adsorption and release mechanisms. The maximum loaded amount of IBU was attained for organo-phillipsite modified with HDTMA-Br (PHB), which showed a complete bilayer micellar structure. Whenever a patchy bilayer micellar structure formed, the lowest adsorptions of IBU were observed. Equilibrium adsorption results were fit using Langmuir, Sips, and Toth models. Pseudo-first-order and pseudo-second-order fits to the loading kinetic data provided significant goodness of fit. Good fits to the release kinetic data were obtained using first-order and Weibull equations, shedding new light on the release mechanism of IBU from phillipsite. The active amount of IBU on the modified zeolite surface was almost totally available for pharmaceutical purposes.