Alina Murariu

The encapsulation effect of UV molecular absorbers into biocompatible lipid nanoparticles

The efficiency of a cosmetic product depends not only on the active ingredients, but also on the carrier system devoted to improve its bioavailability. This article aims to encapsulate two couples of UV molecular absorbers, with a blocking action on both UV-A and UV-B domains, into efficient lipid nanoparticles. The effect of encapsulation on the specific properties such as sun protection factor and photostability behaviour has been demonstrated. The lipid nanoparticles with size range 30-350 nm and a polydispersity index between 0.217 and 0.244 are obtained using a modified high shear homogenisation method. The nanoparticles had spherical shapes with a single crystallisation form of lipid matrices characteristic for the least ordered crystal structure (α-form). The in vitro determination of photoprotection has led to high SPF ratings, with values of about 20, which assure a good photoprotection and filtering about 95% of UV radiation. The photoprotection effect after irradiation stage was observed to be increased more than twice compared to initial samples as a result of isomerisation phenomena. All the results have shown that good photoprotection effect and improved photostability could be obtained using such sunscreen couples, thus demonstrating that UV absorbers-solid lipid nanoparticles are promising carriers for cosmetic formulations.

Effect of UV Sunscreens Loaded in Solid Lipid Nanoparticles: A Combinated SPF Assay and Photostability

The aim of this investigation was to obtain lipid nanoparticles loaded with different sunscreen agents in order to achieve enhanced photoprotection and to decrease the amount of UV – absorbers, with preserving at the same time a high sun protection factor. The developed formulations combined different types of additives including a mixture of non-ionic surfactant and lechitine with two lipids as solid matrix to obtain favourable stable lipid formulations. The research work could be concluded as successefully production of lipid nanoparticles loaded with UV-A and UV-B absorbers (with average size less than 100 nm) that may represent useful UV-blocking systems in sunscreen products for cosmetical purpose.

Antioxidant Activity of Solid Lipid Nanoparticles Loaded with Umbelliferone

The objective of this investigation was to develop solid lipid nanoparticles (SLNs) of umbelliferone by means of a high shear homogenization technique and to evaluate the efficiency of SLN systems in preserving and enhancing antioxidant activity of the flavonoid active component. The aqueous SLN dispersions combine two structural types of lipid compounds and different types of emulsifiers including a mixture of monoalkyl polyoxyethylene sorbitan with a block copolymer and lecithin. The assessment of umbelliferone stability in aqueous SLN dispersions, the size distribution of lipid nanoparticles loaded with umbelliferone (by DLS technique), as well as the structural changes (FT-IR spectroscopy and differential scanning calorimetry) of these lipid nanomatrices have been investigated. Moreover, the influence of umbelliferone concentration onto entrapment efficiency and antioxidant properties were clearly evidenced on four kinds of lipid nanoparticles. The umbelliferone-loaded SLN prepared with polyethylene glycol sorbitan monostearate shown a mean particle size of 173.4 nm ± 3.279, as well as good entrapment efficiency (EE = 60.70%) and antioxidant properties (AA = 75%).

Antioxidant Capacity of Lipid Nanoparticles Loaded with Rosemary Extract

This work presents a simple, available and effective method for preparation of lipid nanoparticles loaded with a natural extract containing active principles. The purpose of the research is to synthesize new lipid nanoparticles with enhanced antioxidant activity, by using two types of lipid carriers. The lipid nanoparticles were produced by emulsification with high shear homogenisation method using biocompatible emulsifiers with excellent skin compatibility as surfactants. The developed nanoparticles were characterized for particle size, polydispersity index, zeta potential, morphology, crystallinity of the lipid matrices and antioxidant activity. Both types of synthesized lipid nanoparticles exhibit an improved antioxidant activity.

Effect of Drinking Water on Formation of Renal Calculi

The environmental impact on human health is of increasing concern mainly due to the complex interaction between various hazardous factors both on environment and within human organism. The aim of this paper is to investigate possible correlations between the quality parameters of drinking water and the formation of uroliths. The constituents of some kidney calculi sampled after surgery from 90 patients coming from the Horezu – Valcea area have been analysed, this region being identified as having the most cases of kidney lithiasis and that might be related with hard drinking waters. The study has been made during the period of 2004 – 2008. Physical – chemical methods specific for characterization of the quality of drinking waters have been used in parallel with determination of composition and structural characterization by X-ray diffraction, thermal analysis TG, ATD, FT-IR spectroscopy, optical microscopy. Four groups of uroliths have been identified: multiphase oxalate and urate, phosphate (hydroxiapatite) and carbonate, monohydrated oxalate (whewellite), and urate stones. Such research might be useful, from both chemical and biochemical point of view, for identifying the conditions that cause the inhibition of the processes related to kidney calculi formation.

New optical materials based on natural extracts immobilized in different silica polymeric matrices

This study aims at investigating the effect of grape seed extract (GSE) immobilization into individual pores and cages of silica/silsesquioxane networks. It might be considered that, since chemically stable guest molecules are already present in the precursor solution for the synthesis, the entrapping of vegetable extract proceeds without significant modification or other adverse changes during the synthesis. As a consequence, some organic chromophore contained in grape seed extract with enhanced optical functions such as fluorescence and nonlinear optical properties can be perfectly incorporated and preserved into the silica based materials. The grape seed extract was immobilized into inorganic and hybrid silica-silsesquioxane matrices by the sol-gel method and it has been proved to be present as an integral part within the matrices pores and with a uniform size distribution. The fluorescence spectrum was discussed in terms of the effect of the host-guest interaction on these properties, and as a function of template type (glucidic and nonionic template). The formation of GSE doped glassy silica materials was investigated and demonstrated by extensive characterization through UV-VIS and FT-IR spectroscopy, estimation method of polymeric aggregates size (DLS), atomic force microscopy (AFM), and optical properties (by fluorescence and non-linear optical measurements). The results of this study demonstrate that GSE entrapped in inorganic and hybrid polymer networks have promising potential as optical systems, due to the extensive conjugation of polyphenolic mixture from the extract and the protective and optical properties of silica polymers.

Encapsulating the green tea extract by templated sol-gel procedure based on nonionic tensioactive agent of alkenyl succinic anhydrides class

The sol-gel method has been proved to be a suitable approach for the introduction of some sensitive organic substances into inorganic matrices. By extension of bioencapsulation sol-gel method, this article is focused on encapsulation of green tea extract (GTE) in some silica polymeric matrices. Green tea has been extensively used for medical purposes, as promising antioxidant, anti-inflammatory and anti-carcinogenic agents, investigated particularly in the chemoprevention and treatment of skin photodamage. Green tea extract exhibits high content of polyphenols (bioflavonoids), being a rich source of epigalocatehin galat (EGCG) that is over 200 times more potent than vitamin E as scavenger of free radicals and pro-oxidants. The chemical instability of tea polyphenols (TP) can be a major drawback for many applications (e.g. medical application). This has opened the possibility of using a hybrid host network in order to preserve their structural properties. By isolating of organic polyphenol molecules into individual pores and cages of some silica polymers prepared by a templated sol-gel process may confer an appropriate stability for this purpose. In this study the GTE was successfully encapsulated in two inorganic silica and hybrid silica-silsesquioxane polymers, by addition of vegetable extract into a silica precursor solution templated with a nonionic tensioactive agent of vegetal origin (from high oleic sunflower oil), belonging to alkenyl succinic anhydrides class. Experimental studies of the antioxidant stability and fluorescence properties of GTE encapsulated in silica and silica-silsesquioxane polymers are also discussed. Spectral changes observed by UV-VIS-NIR and FT-IR spectroscopy, increased antioxidant activity (after UV-A and UV-B irradiation) tested by chemiluminescence assays and enhanced fluorescence properties by fluorescence measurements and also less aggregation, by DLS and TEM techniques, were observed in encapsulated samples, in contrast with that of native GTE.