Maria Carafa

Lidocaine-loaded non-ionic surfactant vesicles: characterization and in vitro permeation studies.

Our research on topical application of lidocaine-loaded non-ionic surfactant vesicles (NSVs) was prompted by the great interest on new delivery systems for local anaesthetics. This study is focused on a novel formulation of NSVs entrapping lidocaine in the form of a free base (LID) and a hydrochloride (LIDHCl). NSVs were prepared from polyoxyethylene sorbitan monolaurate (Tween20) and cholesterol. The effect of vesicle composition and environmental pH condition (8.6-5.5) on drug encapsulation efficiency (e.e.) was investigated. Experimental strategies involved: freeze-fracture, microscopy technique, dynamic light scattering, permeation through Silastic and mouse abdominal skin, in vitro release kinetics of vesicle-entrapped drugs, fluorescence quenching analyses. Diffusion experiments showed that the flux of charged lidocaine through Silastic membrane was possible only after the vesicle encapsulation. Permeation through mouse abdominal skin of LIDHCl loaded vesicles showed a higher flux and a shorter lag time with respect to classical liposome formulations, while LID permeation rate was quite similar for NSV and liposome formulations. Vesicles were also prepared in the presence of dicetylphosphate (DCP) and N-cetylpyridinium chloride (CP) to obtain negatively and positively charged vesicles respectively, but in this case the e.e. of the drug was negligible. The possible reason of the remarkable lower e.e. observed with charged vesicles was investigated by means of fluorescence quenching experiments.

Preparation and properties of new unilamellar non-ionic/ionic surfactant vesicles

Abstract Non-ionic surfactant vesicles (NSVs) were prepared from polysorbate 20 and cholesterol by means of two different methods: by direct sonication of an aqueous dispersion of the various components (bulk) or by solubilization of the components, evaporation of the organic solvent to form a film inside the vessel used for the preparation and then by sonication (film). The influence of the preparation technique on the properties of the obtained structures was studied. Vesicles with bigger dimensions and higher entrapment efficiency were obtained when sonication was carried out after the film formation. Vesicle formation in the presence of ionic surfactants was investigated in order to evaluate the effect of charged components on vesicle dimensions, entrapment efficiency and stability. Dimethyldioctadecylammonium bromide (DDOA) and cetylpyridinium chloride (CPy) were used to introduce a positive charge in the vesicle structure, while dicetylphosphate (DCP) was used for a negative charge. Better resistance to osmotic stress and higher entrapment efficiency values were obtained with vesicles containing DCP and CPy.

Non-ionic surfactant vesicles in pulmonary glucocorticoid delivery: Characterization and interaction with human lung fibroblasts

Non-ionic surfactant vesicles (NSVs) were proposed for the pulmonary delivery of glucocorticoids such as beclomethasone dipropionate (BDP) for the treatment of inflammatory lung diseases, e.g. asthma, chronic obstructive pulmonary disease and various type of pulmonary fibrosis. The thin layer evaporation method followed by sonication was used to prepare small non-ionic surfactant vesicles containing beclomethasone dipropionate. Light scattering experiments showed that beclomethasone dipropionate-loaded non-ionic surfactant vesicles were larger than unloaded ones and showed a significant (P<0.001) decrease of the zeta potential. The morphological analysis, by freeze-fracture transmission electron microscopy, showed the maintenance of a vesicular structure in the presence of the drug. The colloidal and storage stability were evaluated by Turbiscan Lab Expert, which evidenced the good stability of BDP-loaded non-ionic surfactant vesicles, thus showing no significant variations of mean size and no colloidal phase segregation. Primary human lung fibroblast (HLF) cells were used for in vitro investigation of vesicle tolerability, carrier-cell interaction, intracellular drug uptake and drug-loaded vesicle anti-inflammatory activity. The investigated NSVs did not show a significant cytotoxic activity at all incubation times for concentrations ranging from 0.01 to 1 μM. Confocal laser scanning microscopy showed vesicular carrier localization at the level of the cytoplasm compartment, where the glucocorticoid receptor (target site) is localized. BDP-loaded non-ionic surfactant vesicles elicited a significant improvement of the HLF intracellular uptake of the drug with respect to the free drug solution, drug/surfactant mixtures and empty vesicles used as references. The treatment of HLF cells with BDP-loaded non-ionic surfactant vesicles determined a noticeable increase of the drug anti-inflammatory activity by reducing the secretion of both constitutive and interleukin-1β-stimulated nerve growth factor (as inflammatory index) of 68% and 85%, respectively. Obtained data indicate that the investigated NSVs represent a promising tool as a pulmonary drug delivery system.

Anticancer activity of liposomal bergamot essential oil (BEO) on human neuroblastoma cells.

Citrus extracts, particularly bergamot essential oil (BEO) and its fractions, have been found to exhibit anticancer efficacy. However, the poor water solubility, low stability and limited bioavailability have prevented the use of BEO in cancer therapy. To overcome such drawbacks, we formulated BEO liposomes that improved the water solubility of the phytocomponents and increased their anticancer activity in vitro against human SH-SY5Y neuroblastoma cells. The results warrant further investigation of BEO liposomes for in vivo applications.

Anti-inflammatory activity of novel ammonium glycyrrhizinate/niosomes delivery system: human and murine models.

Today there is a very great deal of interest among members of the global natural products community in investigating new plant constituents. Recent studies demonstrate that liquorice extracts are useful in the treatment of dermatitis, eczema, and psoriasis, with an efficacy comparable to that of corticosteroids. In this work, niosomes made up of surfactants (Tween 85 and Span 20) and cholesterol at various concentrations were prepared to investigate the potential application of niosomes for the delivery of ammonium glycyrrhizinate (AG), useful for the treatment of various inflammatory based diseases. Vesicles were characterized evaluating dimensions, ζ potential, anisotropy, drug entrapment efficiency, stability, cytotoxicity evaluation and skin tolerability. Release profiles of ammonium glycyrrhizinate/niosomes were evaluated in vitro using cellulose membranes. The best formulation was used to evaluate the in vitro/in vivo efficacy of the ammonium glycyrrhizinate/niosomes in murine and human models of inflammation. The AG-loaded non-ionic surfactant vesicles showed no toxicity, good skin tolerability and were able to improve the drug anti-inflammatory activity in mice. Furthermore, an improvement of the anti-inflammatory activity of the niosome delivered drug was observed on chemically induced skin erythema in humans.

A novel co-crosslinked polysaccharide: studies for a controlled delivery matrix

The formulation of a new controlled delivery system, based on a novel type of matrix obtained by the chemical reaction carried out in an aqueous medium on a mixed physical gel of gellan and scleroglucan, is described in this paper. The preparation yielded a new co-crosslinked polysaccharide (CCP) hydrogel, bearing carboxylic groups, that showed a sustained release behaviour that can be modulated by means of calcium ions. For the characterization of CCP, diffusion experiments through the swelled hydrogel were carried out in different environmental conditions and the release from tablets prepared with CCP and a model drug was evaluated. The addition of CaCl2 in the formulation of the dosage forms allowed a further marked reduction in delivery rate to be obtained; this effect is to be related to the free ionized carboxylic groups still present in the gellan moiety of CCP. The different behaviour of Ca+2 and Na+ ions is discussed.

Novel hydrogel system from scleroglucan: synthesis and characterization

New hydrogels obtained by a crosslinking reaction between the polycarboxylated derivative of scleroglucan (sclerox) and 1, 6-hexanedibromide have been prepared and characterized. Different ratios between the alkane dihalide and sclerox yielded products with appreciably different properties. Water uptake by the hydrogel with a low degree of crosslinking was remarkably affected by ionic strength. The diffusion of a model molecule (theophylline) through the swelled crosslinked polymers was studied and the theoretical analysis leading to the calculation of permeability coefficients in different environmental conditions is reported. Tablets prepared with one of the new hydrogels behaved as swellable monolithic systems suitable for sustained drug release.

Factors determining the superior performance of lipid/DNA/protammine nanoparticles over lipoplexes.

The utility of using a protammine/DNA complex coated with a lipid envelope made of cationic 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) for transfecting CHO (Chinese hamster ovary cells), HEK293 (human embryonic kidney cells), NIH 3T3 (mouse embryonal cells), and A17 (murine cancer cells) cells was examined. The widely used DOTAP/DNA lipoplex was employed as a reference. In all the tested cell lines lipid/protamine/DNA (LPD) nanoparticles were more efficient in transfecting cells than lipoplexes even though the lipid composition of the lipid envelope was the same in both devices. Physical-chemical properties were found to control the ability of nanocarriers to release DNA upon interaction with cellular membranes. LPD complexes easily release their DNA payload, while lipoplexes remain largely intact and accumulate at the cell nucleus. Collectively, these data explain why LPD nanoparticles often exhibit superior performances compared to lipoplexes in trasfecting cells and represent a promising class of nanocarriers for gene delivery.

Gellan for the formulation of sustained delivery beads

Gellan beads containing a model molecule, clay, and in most cases oil and a surfactant were prepared. The release from the obtained beads was studied in vitro with different techniques and the effects of the presence of varying amounts of oil in the formulation was investigated. The behaviour of gellan was compared with that of alginate in the same experimental conditions. The results indicate that gellan is suitable for the formulation of sustained release beads and that, for the tested preparations, the presence of oil results in a marked reduction in delivery rate. From release experiments, carried out with the various formulations and with different concentrations of the substances used as models, it can be suggested that the swelling of the matrix seems to be the most likely factor responsible for the overall rate of delivery.

Ultradeformable liposomes as multidrug carrier of resveratrol and 5-fluorouracil for their topical delivery.

Ultradeformable liposomes represent useful formulations able to increase the skin permeation of drug compounds. In this study, resveratrol- and 5-fluorouracil-loaded ultradeformable liposomes were investigated for the potential treatment of non-melanoma skin cancer. The in vitro anticancer activity of ultradeformable liposomes was tested on human skin cancer cells through viability-, cell cycle- and apoptosis-analysis. Furthermore, we tested the percutaneous permeation of ultradeformable liposomes using human stratum corneum and viable epidermis. The co-encapsulation of resveratrol and 5-fluorouracil (multi-drug carrier) in ultradeformable liposomes improved their anticancer activity on skin cancer cells as compared to both the free drug form and the single entrapped agents. These multi-drug ultradeformable liposomes arrest cell proliferation in G1/S, thus modifying the action of 5-fluorouracil and increasing the activity of resveratrol. This effect might depend on the ultradeformable liposomes, which may accumulate in deeper skin layers, thus generating a cutaneous depot from which resveratrol and 5-fluorouracil are gradually released. Resveratrol and 5-fluorouracil co-loaded ultradeformable liposomes could be a new nanomedicine for the treatment of squamous cell carcinoma, i.e., actinic keratosis, Bowens disease, and keratoacanthoma.