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.

Novel drug delivery systems for natural extracts: The case study of Vitis Vinifera extract-SiO2 nanocomposites

Ball Milling technique has been used to prepare for the first time Vitis Vinifera extract-silica nanocomposites (VV-SiO₂ NCs), which combine the pharmacological effects of the extract with the effectiveness of silica as drug delivery system and active component in the treatment of wound healing. Different contents (1.0, 9.0 and 33.0 wt%) of Vitis Vinifera ethanolic extract were loaded into the silica matrix by grinding the extract with fumed silica using a planetary mill apparatus. The effect of the starting mixture composition and milling time on the final products was examined. The efficiency of the milling process was studied by X-ray Powder Diffraction, Nuclear Magnetic Resonance, and Infrared Spectroscopy, indicating that the natural extract was not affected by the increasing of the milling time. The successful loading of the extract was demonstrated by Nitrogen adsorption/desorption measurements, which showed a decrease in the SSA and pore volume of the silica with the increasing of the extract amount. Morphology of the nanocomposites, investigated by Scanning Electron Microscopy, showed an increased agglomeration in the nanocomposites with the increment of the VV extract amount. Studies on the total phenol quantification and antioxidant activity of the natural extract before and after incorporation in the silica matrix were also carried out. The obtained results indicate that the milling process does not alter the VV extract components, which result to be embedded in the silica matrix. An increase of the antioxidant activity with the increment of the extract amount in the nanocomposites, up to values comparable to the pure VV extract, was also observed.

Development of curcumin loaded sodium hyaluronate immobilized vesicles (hyalurosomes) and their potential on skin inflammation and wound restoring

In the present work new highly biocompatible nanovesicles were developed using polyanion sodium hyaluronate to form polymer immobilized vesicles, so called hyalurosomes. Curcumin, at high concentration was loaded into hyalurosomes and physico-chemical properties and in vitro/in vivo performances of the formulations were compared to those of liposomes having the same lipid and drug content. Vesicles were prepared by direct addition of dispersion containing the polysaccharide sodium hyaluronate and the polyphenol curcumin to a commercial mixture of soy phospholipids, thus avoiding the use of organic solvents. An extensive study was carried out on the physico-chemical features and properties of curcumin-loaded hyalurosomes and liposomes. Cryogenic transmission electron microscopy and small-angle X-ray scattering showed that vesicles were spherical, uni- or oligolamellar and small in size (112-220 nm). The in vitro percutaneous curcumin delivery studies on intact skin showed an improved ability of hyalurosomes to favour a fast drug deposition in the whole skin. Hyalurosomes as well as liposomes were biocompatible, protected in vitro human keratinocytes from oxidative stress damages and promoted tissue remodelling through cellular proliferation and migration. Moreover, in vivo tests underlined a good effectiveness of curcumin-loaded hyalurosomes to counteract 12-O-tetradecanoilphorbol (TPA)-produced inflammation and injuries, diminishing oedema formation, myeloperoxydase activity and providing an extensive skin reepithelization. Thanks to the one-step and environmentally-friendly preparation method, component biocompatibility and safety, good in vitro and in vivo performances, the hyalurosomes appear as promising nanocarriers for cosmetic and pharmaceutical applications.

Isoniazid-gelatin conjugate microparticles containing rifampicin for the treatment of tuberculosis

Objectives 

In this work, a new polymeric microparticle system based on gelatin covalently bound to isoniazid (ISN) and containing rifampicin (RFP) was prepared by spray-drying technique. Microparticle aptitude to nebulisation and their capability of interacting with A549, alveolar basal epithelial cells, were evaluated in vitro.

Methods

Microparticles were obtained by spray drying, and their morphology, size, zeta potential, thermotropic behaviour and nebulisation ability were evaluated.

Key findings 

Microparticles were positively charged with a mean size of 4.88 ± 0.3 μm. Microspheres were able to incorporate both RFP and ISN: encapsulation efficiency was 51 ± 6% and 22 ± 1%, respectively. X-ray diffraction study showed a new extensive and flattened diffraction peak providing evidence that the drugs were dispersed into the microparticles. Differential scanning calorimetry analysis confirmed effective interactions between gelatin and drug molecules by the presence of new transition peaks. Fifty-nine per cent of used microparticles were aerosolised. In-vitro toxicity studies on A549 alveolar basal epithelial cells showed that microparticles decreased cytotoxicity in comparison with the RFP solution. Laser scanning confocal microscopy observation confirmed that fluorescent probes delivered by microparticles are efficiently internalised in A549 cells.

Conclusions 

Overall, microparticles based on gelatin covalently bound to ISN and containing RFP showed a promising behaviour for pulmonary drug delivery.

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.

SLN as a topical delivery system for Artemisia arborescens essential oil: in vitro antiviral activity and skin permeation study

The effect of SLN incorporation on transdermal delivery and in vitro antiherpetic activity of Artemisia arborescens essential oil was investigated. Two different SLN formulations were prepared using the hot-pressure homogenization technique, Compritol 888 ATO as lipid, and Poloxamer 188 and Miranol Ultra C32 as surfactants. Formulations were examined for their stability for two years by monitoring average size distribution and zeta potential values. The antiviral activity of free and SLN incorporated essential oil was tested in vitro against Herpes Simplex Virus-1 (HSV-1) by a quantitative tetrazolium-based colorimetric method (MTT), while the effects of essential oil incorporation into SLN on both the permeation through and the accumulation into the skin strata was investigated by using in vitro diffusion experiments through newborn pig skin and an almond oil Artemisia essential oil solution as a control. Results showed that both SLN formulations were able to entrap the essential oil in high yields and that the mean particle size increased only slightly after two years of storage, indicating a high physical stability. In vitro antiviral assays showed that SLN incorporation did not affect the essential oil antiherpetic activity. The in vitro skin permeation experiments demonstrated the capability of SLN of greatly improving the oil accumulation into the skin, while oil permeation occurred only when the oil was delivered from the control solution.

Liposomes and niosomes as potential carriers for dermal delivery of minoxidil

The aim of this work was to formulate minoxidil loaded liposome and niosome formulations to improve skin drug delivery. Multilamellar liposomes were prepared using soy phosphatidylcholine at different purity degrees (Phospholipon 90, 90% purity, soy lecithin (SL), 75% purity) and cholesterol (Chol), whereas niosomes were made with two different commercial mixtures of alkylpolyglucoside (APG) surfactants (Oramix NS10, Oramix CG110), Chol and dicetylphosphate. Minoxidil skin penetration and permeation experiments were performed in vitro using vertical diffusion Franz cells and human skin treated with either drug vesicular systems or propylene glycol-water-ethanol solution (control). Penetration of minoxidil in epidermal and dermal layers was greater with liposomes than with niosomal formulations and the control solution. These differences might be attributed to the smaller size and the greater potential targeting to skin and skin appendages of liposomal carriers, which enhanced globally the skin drug delivery. The greatest skin accumulation was always obtained with non-dialysed vesicular formulations. No permeation of minoxidil through the whole skin thickness was detected in the present study irrespective of the existence of hair follicles. Alcohol-free liposomal formulations would constitute a promising approach for the topical delivery of minoxidil in hair loss treatment.

Niosomes as carriers for tretinoin. III. A study into the in vitro cutaneous delivery of vesicle-incorporated tretinoin

The influence of drug thermodynamic activity and niosome composition, size, lamellarity and charge on the (trans)dermal delivery of tretinoin (TRA) was studied. For this purpose, tretinoin was incorporated at saturated and unsaturated concentrations in both multilamellar (MLV) and unilamellar (UV) vesicular formulations using two different commercial mixtures of alkyl polyglucosides: octyl-decyl polyglucoside and decyl polyglucoside. Positively and negatively charged vesicular formulations were prepared using either stearylamine or dicetylphosphate as a charge inducer. Niosomes made with polyoxyethylene (4) lauryl ether and liposomes made with soy phosphatidylcholine were also prepared and studied. Vesicular formulations were characterised by transmission electron microscopy and optical and light polarized microscopy for vesicle formation and morphology, and by dynamic laser light scattering for size distribution. The effect of the vesicular incorporation of tretinoin on its (trans)dermal delivery through the newborn pig skin was also investigated in vitro using Franz cells, in comparison with a commercial formulation of the drug (RetinA). The amount of tretinoin delivered through and accumulated in the several skin layers was detected by HPLC. Overall, obtained results showed that tretinoin cutaneous delivery is strongly affected by vesicle composition and thermodynamic activity of the drug. In particular, small, negatively charged niosomal formulations, which are saturated with tretinoin, have shown to give higher cutaneous drug retention than both liposomes and commercial formulation. Moreover, interactions between skin and vesicles seem to depend on physico-chemical properties of the main component of the vesicular bilayer.

Niosomes as carriers for tretinoin. II. Influence of vesicular incorporation on tretinoin photostability

In this work, we compared the chemical stability of tretinoin (TRA) in methanol and in vesicular suspensions exposed both to UV and artificial daylight conditions with the aim of evaluating the potential of niosomes as topical carriers capable of improving the stability of photosensitive drugs. Tretinoin-loaded niosomes were prepared from polyoxyethylene (4) lauryl ether (Brij 30), sorbitan esters (Span 40 and Span 60) and a commercial mixture of octyl/decyl polyglucosides (Triton CG110). Liposomes made from hydrogenated (P90H) and non-hydrogenated (P90) soy phosphatidylcholines were also prepared and studied. In order to evaluate the influence of vesicle structure on the photostability of tretinoin, TRA-loaded vesicles were prepared by the film hydration method, extrusion technique and sonication. After UV irradiation, TRA dissolved in methanol degraded very quickly while the incorporation in vesicles always led to a reduction of the photodegradation process. The photoprotection offered by vesicles varied depending on the vesicle structure and composition. After fluorescent light irradiation for 21 days, not all the studied vesicular formulations improved TRA stability when compared with the free drug in methanol. Tretinoin incorporated in P90 or Span vesicles presented a half-life shorter or very close to that of the free drug. However, the inclusion of TRA in P90H liposomes and Brij 30 or Triton CG110 niosomes retarded the drug photodegradation.

Niosomes as carriers for tretinoin. I. Preparation and properties

Tretinoin-loaded niosomes were prepared from polyoxyethylene (4) lauryl ether, sorbitan esters and a commercial mixture of octyl/decyl polyglucosides, in the presence of cholesterol and dicetyl phosphate. Liposomes made of hydrogenated and non-hydrogenated phosphatidylcholine were also prepared as a comparison reference. A study was made of the influence of vesicle composition and preparation method on the vesicle structure (MLV, LUV, SUV), size distribution, entrapment efficiency and in vitro release of incorporated tretinoin. Results showed that in the presence of cholesterol all the amphiphiles used were able to form stable vesicle dispersions with or without tretinoin. Vesicle sizes were dependent on the preparation method, bilayer composition and drug load. Multilamellar (MLV) vesicles were larger than extruded (LUV) and sonicated (SUV) vesicles while drug-loaded vesicles were generally smaller than empty ones. Entrapment efficiencies of tretinoin were always very high especially for multilamellar (91-99%) and extruded (88-98%) vesicles. The in vitro release of tretinoin from the prepared vesicular formulations was studied using the vertical Franz diffusion cells. The rate of drug release through a Silastic membrane from a liposomal and niosomal tretinoin dispersion was generally faster than from a tretinoin solution. Release data showed that tretinoin delivery is mainly affected by the vesicular structure and that tretinoin delivery increased from MLVs to LUVs to SUVs.

Microemulsions for topical delivery of 8-methoxsalen

8-Methoxsalen (8-MOP) and related furocumarins have been extensively used for the treatment of hyperproliferative skin diseases in association with long-wavelength UVA light. In order to develop alternative formulations for the topical administration of 8-MOP, microemulsions were evaluated as delivery vehicles. Six microemulsion formulations were prepared using water, isopropyl myristate (IPM) and Tween((R)) 80: Span((R)) 80: 1,2-Octanediol (3:1:1.2 w/w). The microemulsions were characterized using conductimetric and dynamic light scattering analyses. The ability of the systems to deliver 8-MOP into and through the skin was evaluated in vitro using newborn pig-skin. The in vitro permeation data showed that the novel microemulsions increased the 8-MOP total penetration through the skin by order of 1.9-4.5, as compared with IPM. In general, the accumulation of 8-MOP into the skin was increased by a factor of 1.5-4.5 by the microemulsion systems with respect to their total amount of drug delivered across the skin. These results suggest that the studied microemulsion systems may be appropriate vehicles for the topical delivery of 8-MOP.

Prevention by L-alpha-phosphatidylcholine of antifungal activity in vitro of liposome-encapsulated imidazoles determined by using time-killing curves

The antifungal activity of the imidazole derivatives miconazole and ketoconazole was reduced when they were entrapped in liposomal structures and significant differences were detected between small unilamellar vesicles (SUV) and multilamellar vesicles (MLV). To understand which component of liposomes interfered with the antifungal activity of miconazole and ketoconazole, we examined the influence of pure egg and soy L-alpha-phosphatidylcholine and cholesterol on activity against Candida albicans ATCC E10231 by time killing curves. Association of phospholipids-cholesterol-imidazole leads to an inhibitory effect on the antifungal activity comparable to that shown when miconazole or ketoconazole were entrapped in SUV liposomes or when miconazole and ketoconazole were incubated in the presence of L-alpha-phosphatidylcholine. The antifungal activity determined in the presence of cholesterol was comparable to that observed with the free drugs. Inhibition of the antifungal activity of miconazole and ketoconazole by phospholipids is dependent on the phospholipid concentration but is independent of the source of phospholipids (egg or soy). Cholesterol had no influence on the antifungal activity of the imidazoles, unlike the effect on other antifungal drugs, such as amphotericin B.

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.

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.

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.

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.

Synthesis and mass spectrometric behavior of some new nucleosides as potential anti-HIV agents

The electron-impact (EI) mass spectrometric behaviour of a series of 8-aza-purines derivatized with hydroxymethylcyclopentane and exhibiting cis-trans isomerization in the cyclopentane ring has been studied in detail with the aid of metastable-ion data. Specific fragmentation processes, present in both EI and mass analysed ion kinetic energy spectra of molecular species, allow characterization of the different pairs of stereoisomers. Contrary to what is observed in the case of purine analogs, the presence of a nitrogen atom in position 8 strongly inhibits fragmentation processes related to the heterocycle.

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.

HDL subfractions as altered in cancer patients

Previous studies from the authors' laboratories have shown that cancer patients are characterized by lower levels of high-density lipoprotein cholesterol (HDL-C) compared with those of normal subjects. HDLs are a complex class of lipoproteins which can be divided mainly into two categories, HDL2 and HDL3, that have not only different lipid and protein composition but also different functions. Therefore, for a better understanding of the metabolism of HDL during tumour growth, the different subfractions of HDL (HDL2 and HDL3) were analysed in the serum of neoplastic patients using a rapid and simple high-performance liquid chromatography (HPLC) method for the analysis. The results obtained showed that serum from neoplastic patients exhibits a peculiar pattern in the distribution of HDL subfractions, consisting of a sharp decrease in HDL3 and a consequent increase of the normal HDL2/HDL3 ratio. It is suggested that evaluation of the HDL subfractions may be of clinical relevance for cancer status and that due to its simplicity, short analytical time and small sample volume required, the HPLC technique used in this study can be easily applied to routine analysis in cancer patients.

Macrocyclic polyesters. I. A novel class of 1,3-butandiol derivatives as potential antimicrobial agents

This paper reports the synthesis of a novel class of macrocyclic tetraesters containing 1,3-butandiol sub-units by reacting the stannolan derivative of the diol with diacyl chloride. The structure of the possible isomers was assigned by spectroscopic data and comparison with samples otherwise prepared. Preliminary screening revealed that these compounds have low antimicrobial activity, although it is higher than that of the starting diol.

Variations of serum lipoproteins during cell proliferation induced by lead nitrate

In the present study serum lipoproteins were investigated during cell proliferation induced by a potent mitogen, lead nitrate. A strong decrease in HDL2 and a concomitant increase in HDL3 were observed in lead-treated rats. The recovery of normal lipoprotein pattern took place together with the regression of hyperplastic process. Since a decrease in HDL also occurs under other conditions of cell growth, we hypothesize that a decrease in HDL, mainly in HDL2 subfraction, may represent a generalized phenomenon related to massive cell proliferation.

Hepatic glucose-6-phosphate dehydrogenase, cholesterogenesis, and serum lipoproteins in liver regeneration after partial hepatectomy

Liver regeneration after partial hepatectomy was used as an experimental model for studying mammalian cell division and replication. The rate of cell proliferation in this hyperplastic model was correlated with hepatic de novo synthesis of cholesterol, with the hexose monophosphate shunt pathway of glucose metabolism, and with serum lipoproteins. An increase of hepatic cholesterol esters and of incorporation of tritiated water in cholesterol esters was observed at 24 hr after partial hepatectomy. Partial hepatectomy also resulted in an increase of hepatic glucose-6-phosphate dehydrogenase and in alteration of serum lipoproteins, primarily due to a selective decline in high density lipoprotein fraction.