Anna Maria Maccioni

Stability studies of new cosmetic formulations with vegetable extracts as functional agents

A formulation study, using increasing amounts of Sepigel 305 as an emulsifier, has been carried out to find new O/W emulsions and value their stability also in presence of vegetable extracts. Stability results have been compared with those obtained from formulations described in the National Formulary of Italian Pharmacopoeia X and functionalised by us with the same vegetable extracts. By using centrifugation and accelerated ageing tests capable of bringing out the gelling and thermostability properties of Sepigel 305, the study emphasised that the new gel emulsions have a greater stability compared to the other formulations.

Preservative systems containing essential oils in cosmetic products.

The aim of this study was to evaluate the antimicrobial activity of selected essential oils (Laurus nobilis, Eucalyptus globulus and Salvia officinalis), both alone and in combination, in cosmetic preparations characterized by an increasing risk of microbial contamination, i.e. an O/W skin cream, a hydrogel and a non‐alcoholic hydrolyte. Their potential synergistic effect in combination with the usual cosmetic preservatives at low concentrations (up to 200‐fold less than usual) was also investigated.

Composition Influence on Pulmonary Delivery of Rifampicin Liposomes

The effects of lipid concentration and composition on the physicochemical properties, aerosol performance and in vitro toxicity activity of several rifampicin-loaded liposomes were investigated. To this purpose, six liposome formulations containing different amounts of soy phosphatidylcholine and hydrogenated soy phosphatidylcholine, with and without cholesterol and oleic acid, were prepared and fully characterized. Uni- or oligo-lamellar, small (~100 nm), negatively charged (~60 mV) vesicles were obtained. Lipid composition affected aerosol delivery features of liposomal rifampicin; in particular, the highest phospholipid concentration led to a better packing of the vesicular bilayers with a consequent higher nebulization stability. The retention of drug in nebulized vesicles (NER%) was higher for oleic acid containing vesicles (55% ± 1.4%) than for the other samples (~47%). A549 cells were used to evaluate intracellular drug uptake and in vitro toxicity activity of rifampicin-loaded liposomes in comparison with the free drug. Cell toxicity was more evident when oleic acid containing liposomes were used.

Development of novel diolein-niosomes for cutaneous delivery of tretinoin: influence of formulation and in vitro assessment.

UNLABELLED This work describes innovative niosomes, composed of diolein alone or in association with the hydrophilic penetration enhancer Labrasol(®), as carriers for cutaneous drug delivery. The model drug was tretinoin and conventional, and Labrasol(®) containing liposomes was used as controls to evaluate the influence of vesicle composition and the role of Labrasol(®) on vesicle physico-chemical properties and performance as skin delivery system. Vesicles, prepared by the thin film hydration technique, were characterized in terms of size distribution, morphology, zeta potential, structure, incorporation efficiency, and rheological properties. The influence of carrier composition on tretinoin delivery to human skin was evaluated by in vitro percutaneous experiments, while formulation distribution on human skin and cellular uptake in human keratinocytes were studied using confocal laser scanning microscopy. RESULT showed that tretinoin loaded diolein-niosomes formed unilamellar vesicles very similar in physico-chemical properties to liposomes. The role of Labrasol(®) was similar in niosomes and liposomes. Its addition affected vesicle structure and size, by formation of an interdigitate bilayer with higher curvature and larger vesicle size, and rheological properties. Indeed, the presence of Labrasol(®) allowed both niosomes and liposomes to shift from Newtonian to pseudo-plastic behavior. Confocal laser microscopy highlighted an important contemporaneous deposition of hydrophilic and lipophilic vesicle components in stratum corneum and a high vesicle affinity for skin appendages when Labrasol(®) was added to the diolein-niosomes. Moreover, all samples were internalized in human keratinocytes in vitro.

Cavitation effect on chitosan nanoparticle size: a possible approach to protect drugs from ultrasonic stress.

The objective of this study was to verify the influence of different modes of ultrasonic radiation on both the mean diameter and the polydispersity index (PI) of chitosan (CH) nanoparticles, which were prepared by means of the ionotropic gelation method. The variations in duration, intensity and mode of cycle of ultrasonic radiation allowed us to highlight several optimal treatments in order to obtain a potential carrier for site-specific drug delivery. Despite the high utility, ultrasound may be a risk factor for sensitive drug-loaded nanoparticles; in order to protect the drug from thermal or mechanical stress, the effects of ultrasonic radiation only on the CH dispersion (instead of the chitosan/tripolyphosphate (TPP) mixture) were studied, without damaging the drug added to the TPP solution. The increase of the wave amplitude, mode of cycle and time of sonication decreased the particle mean diameter; moreover, the mode of cycle showed a greater effect than the other parameters on the PI of the nanoparticle system. Both the mean diameter and the PI of CH nanoparticles increased with increasing CH concentration. The application of ultrasound only on the CH dispersion showed interesting results, particularly in regard to formulations prepared from low and medium molecular weight chitosan.

New cycloalkylpyrazoles as potential cyclooxygenase inhibitors.

In this study some cycloalkyl-3-(N-substituted carbamoyl)-1-phenylpyrazoles have been synthesized in order to screen their capability to inhibit human cyclooxygenase. The synthetic pathway is based on the well known property of nitrilimines to undergo 1,3-dipolar cycloaddition reactions. The structures of all the synthesized compounds have been elucidated by means of both analytical and spectroscopic methods.

Phospholipid-detergent systems: effects of polysorbates on the release of liposomal caffeine ☆

Abstract It is well known that surfactants are capable of interacting with phospholipid vesicles leading to different aggregated structures and finally to mixed micellar systems. By means of diffusion experiments with Valia-Chien cells the effect of different vesicular structures (MLV and SUV) and that of three polysorbates on the release of a model drug (caffeine) from various vesicle formulations was studied. Obtained results indicate that a remarkable delayed/sustained caffeine release is obtained only with the MLV preparations and that the presence of increasing surfactant concentrations initially leads to a further decrease of drug delivery rate and then to a faster release that reaches a maximum when only mixed micelles are present. The variation of the observed effects with the different tested surfactants, in relation to their lipophilicity (HLB values), is also discussed.

Glycerosomes: Use of hydrogenated soy phosphatidylcholine mixture and its effect on vesicle features and diclofenac skin penetration.

In this work, diclofenac was encapsulated, as sodium salt, in glycerosomes containing 10, 20 or 30% of glycerol in the water phase with the aim to ameliorate its topical efficacy. Taking into account previous findings, glycerosome formulation was modified, in terms of economic suitability, using a cheap and commercially available mixture of hydrogenated soy phosphatidylcholine (P90H). P90H glycerosomes were spherical and multilamellar; photon correlation spectroscopy showed that obtained vesicles were ∼131nm, slightly larger and more polydispersed than those made with dipalmitoylphosphatidylcholine (DPPC) but, surprisingly, they were able to ameliorate the local delivery of diclofenac, which was improved with respect to previous findings, in particular using glycerosomes containing high amount of glycerol (20 and 30%). Finally, this drug delivery system showed a high in vitro biocompatibility toward human keratinocytes.

Physico-chemical characterization of succinyl chitosan-stabilized liposomes for the oral co-delivery of quercetin and resveratrol

In the present work, quercetin and resveratrol, natural polyphenols with strong antioxidant and anti-inflammatory properties, were co-loaded in polymer-associated liposomes conceived for oral delivery, by exploiting the potential of pH-sensitive succinyl-chitosan. Chitosan was succinylated, characterized by Nuclear Magnetic Resonance spectroscopy and Gel Permeation Chromatography, and used to form a protective shell on the surface of liposomes. The physico-chemical properties of the succinyl-chitosan liposomes were assessed by light scattering, zeta potential, cryogenic transmission electron microscopy, and small angle X-ray scattering. Small, spherical, uni- and bilamellar vesicles were produced. The succinyl-chitosan shell increased not only the physical stability of the vesicular system, as demonstrated by accelerated stability tests, but also the release of the polyphenols to a greater extent at pH 7.0, mimicking the intestinal environment. The proposed approach based on polyphenol vesicular formulations may be of value in the treatment of pre-cancerous/cancerous intestinal conditions associated with inflammation and oxidative stress.

Determination of bezafibrate concentration by high performance liquid-chromatography in serum of rats treated with lead nitrate.

In the present study, the bezafibrate levels were measured in serum of rats treated with lead nitrate using a high performance liquid chromatography (HPLC) method. The results have shown that the peak corresponding to bezafibrate in the chromatogram is reduced in serum of rats treated with bezafibrate plus lead, indicating that lead treatment accelerates the metabolism of bezafibrate in rats.