Resveratrol proniosomes as a convenient nanoingredient for functional food.

Proniosomes are free-flowing powders composed of water-soluble carriers blended with surfactants, which form niosomes upon hydration. In this work, proniosomal formulations containing the natural antioxidant resveratrol (RSV) were prepared and fully characterized. A pre-formulation study on RSV-loaded niosomes was carried out to determine the most promising ratio between the two surfactants, Tween 20 and Span 60, in terms of entrapment efficiency and antioxidant activity. The optimized formulae were subsequently adapted to be prepared as proniosomes by the slurry method, including lactose or maltodextrin as carriers. The impact of surfactants and carriers properties on size, entrapment efficiency and release kinetics of proniosomes were evaluated. In vitro release of RSV in simulated gastric and intestinal media was determined, as well as the vesicular stability. Moreover, the biocompatibility of the formulations was determined on intestinal cells in vitro. Overall, the developed proniosomes provide promising nanoingredient for functional food, improving resveratrol stability and bioavailability.

Penetration enhancer-containing vesicles: composition dependence of structural features and skin penetration ability.

In this work, we focused on how composition and preparation method of vesicles might affect their morphological features and delivery performances. Penetration Enhancer-containing Vesicles, PEVs, vesicles containing a water miscible penetration enhancer (Transcutol® P; 10%, 20%, 30% v/v) and encapsulating diclofenac sodium, were formulated and compared with conventional liposomes. A cheap and unpurified commercial mixture of phospholipids, fatty acids, and triglycerides (Phospholipon® 50) was used, and the effects of this heterogeneous composition (along with the presence or absence of transcutol and the production method) on vesicle morphology, size, surface charge, drug loading, and stability were investigated. The variations in vesicle structure, bilayer thickness, and number of lamellae were assessed by TEM and Small and Wide Angle X-ray Scattering, which also proved the liquid state of the vesicular bilayer. Further, vesicles were evaluated for ex vivo (trans)dermal delivery, and their mode of action was studied performing a pre-treatment test and confocal laser scanning microscopy analyses. Results showed the formation of multi- and unilamellar vesicles that provided improved diclofenac delivery to pig skin, influenced by vesicle lipid composition and structure. Images of the qualitative CLSM analyses support the conclusion that PEVs enhance drug transport by penetrating intact the stratum corneum, thanks to a synergic effect of vesicles and penetration enhancer.

Nanocrystals as tool to improve piroxicam dissolution rate in novel orally disintegrating tablets.

In this paper, orally disintegrating tablets (ODT) were prepared using nanocrystal formulations in order to optimise dissolution properties of lipophilic, poorly soluble drug piroxicam (PRX). Different nanocrystal formulations were prepared using a high pressure homogenisation technique and poloxamer 188 as stabiliser. Characterisation of PRX nanocrystal ODT was carried out by infrared spectroscopy (FTIR), X-ray powder diffractometry (XRPD), differential scanning calorimetry and photon correlation spectroscopy. Dissolution study of PRX ODT was performed in distilled water (pH 5.5) and was compared to that of PRX coarse suspension ODT, PRX/poloxamer 188 physical mixture and bulk PRX samples. The XRPD and FTIR studies demonstrated that the homogenisation process led to a polymorphic transition from form I (bulk commercial PRX) to form III and monohydrate form of the nanocrystals. All ODT formulations prepared using PRX nanosuspensions showed a higher PRX dissolution rate compared with the ODT prepared with the coarse PRX. Since the solubility of the different PRX polymorphic forms increased only slightly from bulk PRX (form I) to monohydrate, form II and form III, we can conclude that the improvement in PRX dissolution rate is mainly caused by the increased surface-to-volume ratio due to the submicron dimension of the drug particles.

Effect of resveratrol incorporated in liposomes on proliferation and UV-B protection of cells.

The possibility of improving the efficacy of resveratrol, a polyphenol with strong antioxidant and free-radical scavenging properties, on cell proliferation and photoprotection by liposomal incorporation was investigated. Oligolamellar vesicles of different lipid compositions, loaded with resveratrol, were prepared and characterized by evaluating size, zeta potential, incorporation efficiency, electron microscopy and stability over 60 days. The effect of free and liposomal resveratrol on the viability of HEK 293 cells and their photoprotection after UV-B irradiation was assessed by the MTS method. Resveratrol decreased the cell viability at 100microM concentration, while at 10microM increased cell proliferation and also achieved the most effective photoprotection. Photomicrographs of the treated cells from inverted light and fluorescence microscopy demonstrated resveratrol effectiveness at 10microM, as well as its toxicity at higher concentrations, based on changes in cell shape, detachment and apoptotic features. Interestingly, liposomes prevented the cytotoxicity of resveratrol at high concentrations, even at 100microM, avoiding its immediate and massive intracellular distribution, and increased the ability of resveratrol to stimulate the proliferation of the cells and their ability to survive under stress conditions caused by UV-B light.

Liposomes as carriers for verbascoside: stability and skin permeation studies.

In this study the influence of liposomal incorporation on both the stability and the in vitro (trans) dermal delivery of verbascoside was evaluated. The effect of drug entrapment into vesicles on its radical scavenging activity was also studied. Liposomes were obtained from soy phosphatidylcholine and cholesterol according to the film hydration method. Stability of verbascoside-loaded vesicles was studied over 6 months. Results showed that verbascoside can be incorporated in liposomes (E% = 57-66%), preventing its degradation. Stability studies (dynamic lager light scattering [DLLS] measurements and transmission electron microscopy [TEM] visualization) pointed out that vesicles were stable for 90 days and neither verbascoside leakage nor vesicle size alteration occurred during this period. The effects of vesicular incorporation on verbascoside diffusion through skin were investigated in vitro using newborn pig skin. Results showed that liposomes promoted drug accumulation into the stratum corneum but they did not give rise to any significant transdermal verbascoside delivery. Finally, results obtained from a 1, 1-diphenyl-2-pierylhydrazyl (DPPH) radical assay demonstrated that liposomes did not interfere with the radical scavenging activity of verbascoside.

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.

Liposome-incorporated santolina insularis essential oil: preparation, characterization and in vitro antiviral activity.

The effect of liposomal inclusion on the stability and in vitro antiherpetic activity of Santolina insularis essential oil was investigated. In order to study the influence of vesicle structure on the liposome properties, multilamellar and unilamellar vesicles were prepared by the film method and sonication, respectively. Vesicles were obtained from hydrogenated soya phosphatydilcholine and cholesterol. Formulations were examined for their stability for over one year monitoring the drug leakage from vesicles and the average size distribution. The stability of the incorporated oil was verified by studying its quali-quantitative composition. The antiviral activity was studied against Herpes simplex virus type 1 (HSV-1) by plaque reduction and yield reduction assays. Results showed that Santolina insularis essential oil can be incorporated in high amounts in the prepared liposomes, which successfully prevented its degradation. Moreover, stability studies pointed out that vesicle dispersions were stable for at least one year and neither oil leakage nor vesicle size alteration occurred during this period. Antiviral activity assays demonstrated that Santolina insularis essential oil is effective in inactivating HSV-1 and that the activity is principally due to direct virucidal effects. Free essential oil proved to be more effective than liposomal oil and a different activity was discovered which related to the vesicular structure. The ED(50) values, significantly lower when cells were pre-incubated with the essential oil before the virus adsorption, indicate an intracellular mechanism in the antiviral activity of Santolina insularis. Moreover, liposomal Santolina essential oil is non toxic in the range of the concentration tested.

Vesicle formation from hexasubstituted cyclophosphazenic derivatives.

Hexakis[butoxytris(ethoxy)]cyclophosphazene (3a), hexakis[dodecyloxytetrakis (ethoxy)]cyclophosphazene (3b) and hexakis[hexadecyloxyeicosanekis(ethoxy)]cyclophosphazene+ ++ (3c) were synthesised and their ability to form niosomes was studied. All synthesised compounds in the presence of cholesterol were shown to form vesicles, which aggregated strongly. To prevent aggregation, dicetylphosphate was used. The capacity of the sonicated and unsonicated niosomes to encapsulate hydrophile and lipophile molecules was also studied using carboxyfluorescein and diphenylhexatriene.

Synthesis of cis- and trans- 2-arylmethylcycloalkylamines: potential dopaminergic agents.

This paper reports the synthesis and the study of a few new diastereomeric arylmethylcycloalkylamines, tested as potential dopamine receptor active agents. New procedures for the stereospecific synthesis of the arylmethylcycloalkylamines were successfully experimented. All the considered compounds did not show any appreciable dopamine receptor activity.

Effects of in-vitro activity of miconazole and ketoconazole in phospholipid formulations.

Antifungal agents are often used in liposomal formulations in order to improve their pharmacological activity, but how vesicle inclusion can actually affect this is still not fully understood. We report here the results obtained from evaluation of the in-vitro activity against Candida albicans ATCC E10231 of miconazole and ketoconazole in various vesicular and non-vesicular preparations, obtained from egg and soya phospholipids, using time-kill curves. In most cases inclusion of miconazole or ketoconazole in liposomes led to a delayed and decreased activity of the drugs, with detectable differences among the various phospholipid concentrations and different liposomal preparations (small unilamellar vesicle, liposomes, multilamellar aggregates and broken liposomal structures). The results obtained may be helpful in the study of new preparations of antifungal agents entrapped in liposomal structures.