Biomedical subjects

Morena Nocchetti

Publications and source records attributed to Morena Nocchetti.

5 recordsLinked to original sources

PubMed2006

New architectures for zirconium polyphosphonates with a tailor-made open-framework structure.

The use of tetraphosphonic building blocks for the preparation of inorganic-organic zirconium derivatives has led to the formation of novel compounds with a modular structure. This is based on the different connection of polymeric 1D inorganic units covalently connected by organic groups. The different kinds of connections generate two different open-framework structures. These structures have been solved "ab initio" by powder X-ray diffraction data. Very likely, the dimensions of the channels inside these structures may be tuned by the right choice of the interlinking organic group.

Journal Article↗

PubMed2006

Evaluation and optimization of the conditions for an improved ferulic acid intercalation into a synthetic lamellar anionic clay.

PURPOSE: The aim of the study is to optimize the intercalation conditions of ferulic acid (FERH), an antioxidant compound, into Mg-Al-hydrotalcite for a safe skin photoprotection. METHODS: The intercalation products were prepared incubating hydrotalcite (HTlc) in aqueous solutions of FERH sodium salt at different temperatures over 4 and 8 days. Quantitative determination of intercalated FERH was performed by thermogravimetric analysis and morphology by scanning electron microscopy (SEM). FERH stability study was carried out at different pHs and temperatures. FERH was analyzed by reversed phase-high-performance liquid chromatography. Response surface methods (RSMs) were used to assess optimal intercalation conditions and FERH stability. RESULTS: In all intercalation products, FERH content was found to be about 48% w/w except when the intercalation process was carried out at 52 degrees C for 8 days and at 60 degrees C for both 4 and 8 days, which resulted to be 40.39, 39.99, and 34.99%, respectively. The RSM designs showed that intercalation improvement can be achieved by working at pH 6, at temperatures below 40 degrees C, and over 4 days of incubation. CONCLUSIONS: The optimal conditions for a proper FERH intercalation were assessed. The development of a new optimized protocol may improve HTlc-FER complex performances and safety by augmenting dosage and reducing the presence of harmful reactive species in the final formulation.

Aluminum Hydroxide↗

PubMed2005

Anionic clays for sunscreen agent safe use: photoprotection, photostability and prevention of their skin penetration.

The use of sunscreen preparations is recently growing and their efficacy and safety must be taken into account since they are applied on the skin frequently and for many hours. Exposition to sunlight, in fact, can cause sunscreen photodegradation and determine their decrease in UV protection often with the occurrence of allergic and/or toxic degradation products. A high photostability is hence very important for their effectiveness and safety. The aim of this work is to obtain new sunscreen formulations stabilized by intercalating PABA, within the lamellar structures of two kinds of hydrotalcite. PABA was chosen as model sunscreen because of its high photoinstability and photosensitizing properties that nowadays bar its utilization. Both intercalated products showed an increased protection range and, in one case, an improved sunscreen photostability. Sunscreen release from creams containing intercalated or free PABA was evaluated as well. The very low or negligible sunscreen release, obtained from the intercalated product loaded formulations, resulted in a lack of a close contact between skin and filter with the consequence that cutaneous reactions and allergy problems are eliminated. The use of these materials resulted in a good strategic technological approach in order to increase efficacy and safety of solar products.

4-Aminobenzoic Acid↗

PubMed2003

Effect of hydrotalcite-like compounds on the aqueous solubility of some poorly water-soluble drugs.

A new approach of improving drug dissolution properties is described. This method exploits the property of a carrier owing to the hydrotalcite-type anionic clays (HTlc). HTlc is an inorganic layered solid that lodges anionic compounds among its layers. As HTlc dissolves at acidic pH values (pH < 4), the anions intercalated among the layers are promptly released in the medium. In this article some nonsteroidal antiinflammatory drugs were chosen as models of poorly water-soluble drugs. They were intercalated in HTlc and solubility measurements in acidic medium were performed. A remarkable improvement of drug solubility was observed especially in the case of indomethacin.

Aluminum Hydroxide↗

PubMed2002

Preparation, characterization, and structure of zirconium fluoride alkylamino-N,N-bis methylphosphonates: a new design for layered zirconium diphosphonates with a poorly hindered interlayer region.

This paper reports the preparation and characterization of the homologous series of layered zirconium fluoride n-alkylamino-N,N-bis methylphosphonates, of general formula ZrF(O(3)PCH(2))(2)NHC(n)H(2n+1) (n = 1, 2, 3, 4, 5, 6, 8, 9, 10), in which the two phosphonic groups of each diphosphonate building block participate in the assembly of a single lamella, because they are joined to zirconium atoms belonging to the same layer. The crystal structure of one of the series of these zirconium diphosphonates, ZrF(O(3)PCH(2))(2)NHC(5)H(11), has been solved "ab initio" by X-ray powder diffraction data. The structure is monoclinic, space group P2(1)/c. The zwitterionic character of the diphosphonate moiety is a distinctive feature which acts as a structure-orienting factor, generating a layer framework which is different from the other structures known for zirconium phosphates and phosphonates. This compound undergoes a phase transition at 117 degrees C which involves a rearrangement of the interlayer alkyl chains. The structure of the high-temperature phase has been refined by the Rietveld method. Because only one organic residue is associated with two phosphonate tetrahedra, a poorly hindered interlayer region is formed, and alkyl chains bonded to adjacent layers are interdigitated. Preliminary experiments have shown that these compounds are able to intercalate organic molecules, such as n-alkanols, from very dilute water solutions.

Journal Article↗