Christian Celia

Turbiscan lab expert analysis of the stability of ethosomes and ultradeformable liposomes containing a bilayer fluidizing agent.

The stability of vesicular drug carriers containing linoleic acid, as a model of bilayer fluidizing agent, was evaluated using a Turbiscan optical analyzer, an innovative analytical instrument able to determine the long-time stability of colloidal systems. Ethosomes and ultradeformable liposomes were prepared using Phospholipon 100G as the lecithin component, while ethanol and sodium cholate were used for the specific preparation of ethosomes and ultradeformable liposomes, respectively. The advantages of the Turbiscan optical analyzer are: (i) its ability to measure reversible (creaming and sedimentation) and irreversible (coalescence and segregation) destabilization phenomena directly in the sample without any dilution and (ii) to detect these phenomena much earlier and easier than other apparatuses. Turbiscan data showed that both colloidal vesicles demonstrate a good stability during the 3h of the experiment. No modification of Turbiscan backscattering profiles of colloidal suspensions occurred when different amounts of linoleic acid were used to prepare ethosomes and ultradeformable liposomes. No coalescence, sedimentation, flocculation or clarification occurred. The results were very encouraging and confirmed the fact that the Turbiscan optical analyzer can be used to study the stability of colloidal formulations even in the presence of deformable agents.

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.

Effects of Lipid Composition and Preparation Conditions on Physical-Chemical Properties, Technological Parameters and In Vitro Biological Activity of Gemcitabine-Loaded Liposomes

The effects of lipid composition and preparation conditions on the physicochemical and technological properties of gemcitabine-loaded liposomes, as well as the in vitro anti-tumoral activity of various liposome formulations were investigated. Three liposome formulations were investigated: DPPC/Chol/Oleic acid (8:3:1 molar ratio, liposomes A), DPPC/Chol/DPPS (6:3:1 molar ratio, liposomes B) and DPPC/Chol/DSPE-MPEG (6:3:1 molar ratio, liposomes C). Multilamellar liposomes were prepared by using the TLE, FAT and DRV methods, while small unilamellar liposomes were obtained by extrusion through polycarbonate filters. Light scattering techniques were used to characterize liposome formulations. Loading capacity and release profiles of gemcitabine from various liposome formulations were also investigated. Caco-2 cells were used to evaluate in vitro the antitumoral activity of gemcitabine-loaded liposomes with respect to the free drug and also the intracellular drug uptake. Preparation methods and liposome lipid composition influenced both physicochemical parameters and drug delivery features. Liposomes with a size ranging from 200 nm to 7 microm were obtained. The gemcitabine entrapment was higher than that expected probably due to an interaction with the liposome lipid components. The following decreasing loading capacity order was observed: liposome B>liposome C>liposome A. Gemcitabine release from various liposome formulations is modulated by two different processes, i.e. desorption from and permeation through liposomal bilayers. MTT assay showed a greater cytotoxic effect of gemcitabine-loaded liposomes with respect to the free drug. The following decreasing anticancer activity order was observed between the various liposome formulations: liposome C>liposome A>liposome B. The increased anticancer activity is correlated to the ability of the colloidal carrier to increase the intracellular drug uptake. Due to the encouraging results and to the high liposome modularity various applications of potential therapeutic relevance can be envisaged for liposomes.

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.

Colloidal carriers for the enhanced delivery through the skin.

Background: The skin is the largest organ of our body and acts as a protective barrier with sensory and immunological functions. Its peculiar structure influences the passage of bioactives and only its modulation can facilitate the drug dermal/transdermal diffusion. In the past few years research in this field has assured better use of this application area. Methods: One of the most promising approaches is the use of drug delivery devices; this review explains the state of the art of drug transport through the skin by means of vesicular (classic liposomes, Transfersomes, niosomes and ethosomes) and particulate systems. Results/conclusion: Colloidal drug delivery systems are important in the field of drug delivery systems as their different characteristics make them suitable for various purposes.

Folate-targeted supramolecular vesicular aggregates based on polyaspartyl-hydrazide copolymers for the selective delivery of antitumoral drugs

Supramolecular vesicular aggregates (SVAs) have the advantage of combining the safe and biocompatible properties of colloidal vesicular carriers based on phospholipids with those of polymeric materials, i.e. polyaspartyl-hydrazide (PAHy) copolymers. To provide SVAs with a certain tumour selectivity, folate moieties were chemically conjugated to PAHy copolymers. Physicochemical properties (mean sizes, polydispersity index and zeta potential) of folate-targeted SVAs (FT-SVAs) loaded with gemcitabine were evaluated. The antiproliferative and anticancer activity of gemcitabine-loaded FT-SVAs was evaluated against two cancer cell lines, i.e. MCF-7 cells which over-express the folate receptor and the BxPC-3 cells, which do not over-express this receptor. Gemcitabine-loaded FT-SVAs showed a significantly (p < 0.001) greater and more specific in vitro anticancer activity with respect to both the free drug and the drug-loaded conventional liposomes or untargeted SVAs. Confocal microscopy, flow cytometry analysis and beta-scintillation highlighted that FT-SVAs were able to interact with MCF-7 cells after just 3 h and to increase the amount internalization in cells over-expressing the folate receptor. The in vivo biodistribution and pharmacokinetic experiments showed that gemcitabine-loaded SVAs and FT-SVAs were removed from the circulatory system at a slower rate than the native drug and a prolonged gemcitabine plasma concentration was observed for up to 16 h. SVAs were accumulated mainly in the lungs, spleen and kidneys, while FT-SVAs were also up taken by brain. These interesting and stimulating results suggest the existence of a possible in vivo application of SVAs and encourage the use of folate as a targeting agent in anticancer therapy.

Polyethylene glycol (PEG)-dendron phospholipids as innovative constructs for the preparation of super stealth liposomes for anticancer therapy

Pegylation of nanoparticles has been widely implemented in the field of drug delivery to prevent macrophage clearance and increase drug accumulation at a target site. However, the shielding effect of polyethylene glycol (PEG) is usually incomplete and transient, due to loss of nanoparticle integrity upon systemic injection. Here, we have synthesized unique PEG-dendron-phospholipid constructs that form super stealth liposomes (SSLs). A β-glutamic acid dendron anchor was used to attach a PEG chain to several distearoyl phosphoethanolamine lipids, thereby differing from conventional stealth liposomes where a PEG chain is attached to a single phospholipid. This composition was shown to increase liposomal stability, prolong the circulation half-life, improve the biodistribution profile and enhance the anticancer potency of a drug payload (doxorubicin hydrochloride).

Paclitaxel-loaded ethosomes®: potential treatment of squamous cell carcinoma, a malignant transformation of actinic keratoses.

Topical application of anticancer drugs for the treatment of malignancies represents a new challenge in dermatology, potentially being an alternative therapeutic approach for the efficacious treatment of non-melanoma skin cancer, that is, actinic keratoses, and malignant lesions of the skin caused by ultraviolet radiation. Anti-proliferative and antimitotic drugs, including many of the taxanes, are currently under investigation for the treatment of cutaneous malignant transformation of actinic keratoses, particularly the squamous cell carcinoma. Paclitaxel-loaded ethosomes® are proposed as topical drug delivery systems for the treatment of this pathology due to their suitable physicochemical characteristics and enhanced skin penetration ability for deep dermal delivery. Our in vitro data show that the skin application of paclitaxel-loaded ethosomes® improved the permeation of paclitaxel in a stratum corneum-epidermis membrane model and increased its anti-proliferative activity in a squamous cell carcinoma model as compared to the free drug. The results obtained encouraged the use of the paclitaxel-loaded ethosomes® as the formulation for the potential treatment of squamous cell carcinoma, a malignant transformation of actinic keratoses.

Shrinkage of pegylated and non-pegylated liposomes in serum

An essential requisite for the design of nanodelivery systems is the ability to characterize the size, homogeneity and zeta potential of nanoparticles. Such properties can be tailored in order to create the most efficient drug delivery platforms. An important question is whether these characteristics change upon systemic injection. Here, we have studied the behavior of phosphatidylcholine/cholesterol liposomes exposed to serum proteins. The results reveal a serum-induced reduction in the size and homogeneity of both pegylated and non-pegylated liposomes, implicating the possible role of osmotic forces. In addition, changes to zeta-potential were observed upon exposing liposomes to serum. The liposomes with polyethylene glycol expressed different characteristics than their non-polymeric counterparts, suggesting the potential formation of a denser protein corona around the non-pegylated liposomes.

Liposomal delivery improves the growth-inhibitory and apoptotic activity of low doses of gemcitabine in multiple myeloma cancer cells

Gemcitabine-loaded pegylated unilamellar liposomes (200 nm) were proposed for the treatment of multiple myeloma cancer disease. Physicochemical and technological parameters of liposomes were evaluated by using laser light scattering and gel permeation chromatography. The growth-inhibitory activity of gemcitabine-loaded liposomes compared to the free drug was assayed in vitro on U266 (autocrine, interleukin-6-independent) and INA-6 (IL-6-dependent) multiple myeloma cell lines. Liposomes noticeably improved the growth-inhibitory activity of gemcitabine in terms of both dose-dependent and incubation-time effects. Liposomal delivery of gemcitabine consistently and significantly increased induction of apoptosis and caused a complete inhibition of proliferation. Liposomes were able to interact with multiple myeloma cells as demonstrated by confocal laser scanning microscopy and hence to improve the intracellular gemcitabine delivery. Gemcitabine-loaded liposomes were much more effective in vitro than the free drug. This formulation may offer even more in vivo advantages both in terms of drug pharmacokinetic and biodistribution.