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Recently, many studies have shown that plant metabolites, such as geraniol (GER), may exert anti-inflammatory effects in neurodegenerative diseases and, in particular, Parkinson's disease (PD) models. Unfortunately, delivering GER to the CNS via nose-to-brain is not feasible due to its irritant effects on the mucosae. Therefore, in the present study β-cyclodextrin (βCD) and its hydrophilic derivative hydroxypropyl-beta-cyclodextrin (HPβCD) were selected as potential carriers for GER nose-to-brain delivery. Inclusion complexes were formulated and the biocompatibility with nasal mucosae and drug bioavailability into cerebrospinal fluid (CSF) were studied in rats. It has been demonstrated by DTA, FT-IR and NMR analyses that both the CDs were able to form 1:1 GER-CD complexes, arising long-term stable powders after the freeze-drying process. GER-HPβCD-5 and GER-βCD-2 complexes exhibited comparable results, except for morphology and solubility, as demonstrated by SEM analysis and phase solubility study, respectively. Even though both complexes were able to directly and safely deliver GER to CNS, GER-βCD-2 displayed higher ability in releasing GER in the CSF. In conclusion, βCD complexes can be considered a very promising tool in delivering GER into the CNS via nose-to-brain route, preventing GER release into the bloodstream and ensuring the integrity of the nasal mucosa.

Nanostructured Lipid Carriers (NLC) were investigated with the purpose of promoting skin permeation of the highly lipophilic β-carotene (BC) across the stratum corneum (SC) barrier so that it may perform its antioxidant properties in photo-aging and epithelial skin cancer prevention. Two differently sized NLC samples were developed using stearic acid and squalene as lipid matrix and evaluated in comparison with Microstructured Lipid Carriers (MLC). The carriers were characterized for morphology, size, Z-potential, BC loading and release as well as physical state by means of DSC and XRPD analyses. In vivo penetration of the carriers was assessed on humans by determining BC concentrations within the SC stratum disjunctum and stratum compactum layers removed by means of the tape stripping test in comparison with pure BC. Unlike MLC and pure BC that were mostly retained within the outermost layers of the SC, the NLC sample having the smallest size (about 200 nm) has proved to penetrate more deeply into the SC barrier. Accordingly, the goal of providing β-carotene actions against oxidative damages within the looser skin viable tissues could be envisaged.

In the present work a novel hybrid system for the delivery of two first-line antitubercular drugs, rifampicin (RIF) and isoniazid (INH), was designed. In order to control the release of the drugs and improve the efficiency of conventional carriers, like liposomes or solid lipid nanoparticles (SLNs), the new systems were developed by embedding SLNs into lecithin-based liposomes through the reverse-phase evaporation method. The hybrid system was characterized and compared to SLNs and liposomes in terms of size, encapsulation efficiency, morphology, and drug release. Detailed structural data and further evidence of the successful formation of the hybrid nanoparticles were obtained by applying small-angle neutron scattering (SANS). The hybrid system displayed a particle size comparable to liposomes and a high encapsulation efficiency. Morphological results obtained by atomic force microscopy (AFM) highlighted the possible presence of SLNs into the phospholipid bilayer; this hypothesis was supported by the slower in vitro release of the hydrophilic drug INH compared to liposomes and SLNs. Moreover, scattering differences of the inner core of the nanoparticles, evidenced in the SANS analysis, further corroborated the successful formation of the hybrid carrier. These novel systems were able to release their content as expected from an efficient dosage form in a perspective of an inhaled administration, improving the stability and the drug release profile with respect to plain liposomes. The physicochemical characterization of our systems opens new avenues towards a better understanding of the formulation of vesicles encapsulating SLNs.

Enhancing oral bioavailability of hydrophilic drugs by encapsulation in lipid-based nanocarriers, including Solid Lipid Nanoparticles (SLN), has been well documented. In this work, high molecular weight heparin was “insolubilized” by an “ion-paring” approach, forming Chitosan/Heparin Polyelectrolyte Complexes (PEC) to promote its encapsulation in SLN. Hybrid PEC-SLN, heparin-loaded SLN (H-SLN) as well as naked PEC were prepared and characterized regarding size, Z potential, morphology, drug loading and drug release. Physicochemical characterization of the nanoparticles was also performed by differential scanning calorimetry (DSC), and Fourier Transform Infra-Red (FTIR) analysis. FITC-labeled naked PEC along with Nile Red labeled PEC-SLN were assessed on CaCo-2 cells to study cytotoxicity as well as cell internalization ability by cytometric and confocal analysis. Transepithelial electrical resistance (TEER) was measured on NCM460 cell monolayers to evaluate whether chitosan may induce a modification of tight junctions’ integrity at epithelial level. Results showed that the minimum size of PEC (around 170 nm) was at pH 5.5 with a positive surface charge and after encapsulation in SLN produced hybrid PEC-SLN with a size of about 370 nm and a negative zeta potential. In comparison to both H-SLN and naked PEC, PEC-SLN were able to achieve a pH-controlled drug release and showed on CaCo-2 cells low toxicity and rapid internalization. Finally, TEER measurements highlighted that the hybrid nanocarriers were internalized without interference in the membrane resistance. Therefore, PEC-SLN could be considered valuable candidate for further in vivo investigations about the systemic bioavailability of oral heparin.

The present study reports about new solid lipid nanoparticle assemblies (SLNas) loaded with rifampicin (RIF) surface-decorated with novel mannose derivatives, designed for anti-tuberculosis (TB) inhaled therapy by dry powder inhaler (DPI). Mannose is considered a relevant ligand to achieve active drug targeting being mannose receptors (MR) overexpressed on membranes of infected alveolar macrophages (AM), which are the preferred site of Mycobacterium tuberculosis. Surface decoration of SLNas was obtained by means of newly synthesized functionalizing compounds used as surfactants in the preparation of carriers. SLNas were fully characterized in vitro determining size, morphology, drug loading, drug release, surface mannosylation, cytotoxicity, macrophage internalization extent and ability to bind MR, and intracellular RIF concentration. Moreover, the influence of these new surface functionalizing agents on SLNas aerodynamic performance was assessed by measuring particle respirability features using next generation impactor. SLNas exhibited suitable drug payload, in vitro release, and more efficient ability to enter macrophages (about 80%) compared to bare RIF (about 20%) and to non-functionalized SLNas (about 40%). The involvement of MR-specific binding has been demonstrated by saturating MR of J774 cells causing a decrease of RIF intracellular concentration of about 40%. Furthermore, it is noteworthy that the surface decoration of particles produced a poor cohesive powder with an adequate respirability (fine particle fraction ranging from about 30 to 50%). Therefore, the proposed SLNas may represent an encouraging opportunity in a perspective of an efficacious anti-TB inhaled therapy.

Self-assembled organogelators were explored as artificial stratum corneum (SC) models for the in vitro skin permeation assessment. Four SC models consisting of binary (organogels) or ternary (microemulsion-based organogels) mixtures were developed using stearic acid, tristearin, or sorbitan tristearate, at two different concentrations, gelled in squalene. The permeation of lipophilic butyl-methoxydibenzoylmethane and hydrophilic methylene blue as the permeant compounds across the SC models was compared with ex vivo experiments using excised porcine ear skin. A multi-analytical approach was adopted to provide detailed understanding about organogelator organization within the SC models and find possible parameters playing key-roles in SC permeation prediction. The SC models were investigated for gelling properties and microstructure. Parameters such as gel occurrence, organogelator concentration, and rheological properties appeared as negligible conditions for skin permeation prediction. Conversely, arrangement packing, interactions, and crystallinity extent of the self-assembled organogelator were found to play a fundamental role in the simulation of SC barrier function according to the permeant feature.

Context: LR-peptide, a novel hydrophilic peptide synthetized and characterized in previous work, is able to reduce the multi-drug resistance response in cisplatin (cDPP) resistant cancer cells by inhibiting human thymidylate synthase (hTS) overexpressed in several tumors, including ovarian and colon-rectal cancers, but it is unable to enter the cells spontaneously. Objective: The aim of this work was to design and characterize liposomal vesicles as drug delivery systems for the LR peptide, evaluating the possible benefits of the pH-responsive feature in improving intracellular delivery. Materials and methods: For this purpose, conventional and pH-sensitive liposomes were formulated, compared regarding their physical-chemical properties (size, PDI, morphology, in vitro stability and drug release) and studied for in vitro cytotoxicity against a cDDP-resistant cancer cells. Results and discussion: Results indicated that LR peptide was successfully encapsulated in both liposomal formulations but at short incubation time only LR loaded pH-sensitive liposomes showed cell inhibition activity while for long incubation time the two kinds of liposomes demonstrated the same efficacy. Conclusions: Data provide evidence that acidic pH-triggered liposomal delivery is able to significantly reduce the time required by the systems to deliver the drug to the cells without inducing an enhancement of the efficacy of the drug.

With the aim of developing new drug carriers for inhalation therapy, we report here an in depth investigation of the structure of multilamellar liposomes loaded with two well-established anti-tubercular (anti-TB) drugs, isoniazid (INH) and rifampicin (RIF), by means of small-angle neutron-scattering (SANS) analysis. Unloaded, single drug-loaded and co-loaded liposomes were prepared using different amounts of drugs and characterized regarding size, encapsulation efficiency and drug release. Detailed information on relevant properties of the investigated host-guest structures, namely the steric bilayer thickness, particle dispersion, number of lamellae and drug localization was studied by SANS. Results showed that RIF-liposomes were less ordered than unloaded liposomes. INH induced a change in the inter-bilayer periodical spacing, while RIF-INH co-loading stabilized the multilamellar liposome architecture, as confirmed by the increment of the drug loading capacity. These findings could be useful for the understanding of in vitro and in vivo behavior of these systems and for the design of new drug carriers, intended for inhaled therapy.

Recent biomedical applications of clay materials have included organically modified clays or clay minerals with the purpose of modifying and improving drug biological activity. The present research aims to explore the potential benefits provided by a raw bentonite (Bt) modified by gentamicin (GM) adsorbed within montmorillonite interlayers in the management of cutaneous infectious diseases. Information arisen from controlled X-ray powder diffraction, thermogravimetry coupled with evolved gas mass spectrometry, and molecular dynamics simulations pointed out GM monolayer arrangement within montmorillonite framework without producing substantial effects on the layer periodicity. Concerning skin biomedical application, unlike the pure antibiotic permeating along the trans-follicular pathway across stratum corneum, the organo-modified Bt/GM would favor the trans-epidermal route along inter-cluster corneocyte region, as in vivo skin penetration studies by means of tape stripping test indicated. Based on the results obtained, GM intercalation could represent a potential advantageous approach allowing a long-term Bt/GM reservoir for sustained antibacterial activity.

To evaluate the potential effects of PEGylated pH-sensitive liposomes on the intracellular activity of a new peptide recently characterized as a novel inhibitor of the human thymidylate synthase (hTS) over-expressed in many drug-resistant human cancer cell lines. Peptide-loaded pH-sensitive PEGylated (PpHL) and non-PEGylated liposomes (nPpHL) were carefully characterized and delivered to cis-platinum resistant ovarian cancer C13* cells; the influence of the PpHL on the drug intracellular activity was investigated by the Western Blot analysis of proteins involved in the pathway affected by hTS inhibition. Although PpHL and nPpHL showed different sizes, surface hydrophilicities and serum stabilities, both carriers entrapped the drug efficiently and stably demonstrating a pH dependent release; moreover, the different behavior against J774 macrophage cells confirmed the ability of PEGylation in protecting liposomes from the reticuloendothelial system. Comparable effects were instead observed against C13* cells and biochemical data by immunoblot analysis indicated that PEGylated pH-sensitive liposomes do not modify the proteomic profile of the cells, fully preserving the activity of the biomolecule. PpHL can be considered as efficient delivery systems for the new promising anti-cancer peptide.

Recently, solid lipid nanoparticles (SLNs) have attracted increasing attention owing to their potential as an oral delivery system, promoting intestinal absorption in the lymphatic circulation which plays a role in disseminating metastatic cancer cells and infectious agents throughout the body. SLN features can be exploited for the oral delivery of theranostics. Therefore, the aim of this work was to design and characterise self-assembled lipid nanoparticles (SALNs) to encapsulate and stabilise iron oxide nanoparticles non-covalently coated with heparin (Fe@hepa) as a model of a theranostic tool. SALNs were characterised for physico-chemical properties (particle size, surface charge, encapsulation efficiency, in vitro stability, and heparin leakage), as well as in vitro cytotoxicity by methyl thiazole tetrazolium (MTT) assay and cell internalisation in CaCo-2, a cell line model used as an indirect indication of intestinal lymphatic absorption. SALNs of about 180 nm, which are stable in suspension and have a high encapsulation efficiency (>90%) were obtained. SALNs were able to stabilise the heparin coating of Fe@hepa, which are typically unstable in physiological environments. Moreover, SALNs–Fe@hepa showed no cytotoxicity, although their ability to be internalised into CaCo-2 cells was highlighted by confocal microscopy analysis. Therefore, the results indicated that SALNs can be considered as a promising tool to orally deliver theranostic Fe@hepa into the lymphatic circulation, although further in vivo studies are needed to comprehend further potential applications.

This study describes the development of new mannosylated Solid Lipid Nanoparticle assemblies (SLNas) delivering rifampicin for an inhaled treatment of tuberculosis. SLNas were surface engineered with mannose residues to recognize mannose receptors located on infected alveolar macrophages and facilitate cell internalization. Two sets of SLNas were produced by the melt emulsifying technique using biocompatible lipid components, i.e. cholesteryl myristate combined with palmitic acid (PA set) or tripalmitin (TP set), in the presence of the targeting moiety, methyl α-d-mannopyranoside. Mannosylated SLNas were examined for their physical properties, drug payloads and release, as well as respirability in terms of emitted dose and respirable fraction determined by Next Generation Impactor. The most appropriate formulations were assessed for mannosylation using FTIR, XPS, SEM coupled with EDX analysis, and wettability assay, in comparison with the respective non-functionalized SLNas. Besides, cytotoxicity and cell internalization ability were established on J774 murine macrophage cell line. Mannosylated SLNas exhibited physical properties suitable for alveolar macrophage passive targeting, adequate rifampicin payloads (10-15%), and feasible drug maintenance within SLNas along the respiratory tract before macrophage internalization. Despite respirability impaired by powder cohesiveness, surface mannosylation provided quicker macrophage phagocytosis, giving evidence of an active targeting promotion.

Skin penetration of silica nanoparticles (NP) currently used in pharmaceutical and cosmetic products is a topic of interest not only to evaluate their possible toxicity, but also to understand their behaviour upon contact with the skin and to exploit their potential positive effects in drug or cosmetic delivery field. Therefore, the present work aimed to elucidate the in vivo mechanism by which amorphous hydrophilic silica NP enter human stratum corneum (SC) through the evaluation of the role played by the nanoparticle surface polarity and the human hair follicle density. Two silica samples, bare hydrophilic silica (B-silica, 162±51nm in size) and hydrophobic lipid-coated silica (LC-silica, 363±74nm in size) were applied on both the volar and dorsal side of volunteer forearms. Twelve repetitive stripped tapes were removed from the human skin and evaluated for elemental composition by Energy Dispersive X-ray (EDX) analysis and for silicon content by Inductively Coupled Plasma quadrupole Mass Spectrometry (ICP-MS). All the stripped tapes revealed nanosized structures generally located in the broad spaces between corneocytes and characterized by the same elemental composition (relative weight percentage of silicon and silicon to oxygen weight ratio) than that of the applied samples. However, only about 10% B-silica permeated until the deepest SC layers considered in the study indicating a silica retention in the upper layers of SC, regardless of the hair follicle density. Otherwise, the exposure to LC-silica led to a greater silica skin penetration extent into the deeper SC layers (about 42% and 18% silica following volar and dorsal forearm application, respectively) indicating that the NP surface polarity played a predominant role on that of their size in determining the route and the extent of penetration.

The goal of the work was to evaluate an anti-tubercular strategy based on breathable Solid Lipid Microparticles (SLM) to target alveolar macrophages and to increase the effectiveness of the conventional tuberculosis (TB) therapy. Rifampicin loaded SLM composed of stearic acid and sodium taurocholate were characterized for aerodynamic diameter, surface charge, physical state of the components, drug loading and release as well as drug biological activity on Bacillus subtilis strain. Moreover, SLM cytotoxicity and cell internalization ability were evaluated on murine macrophages J774 cell lines by MTT test, cytofluorimetry and confocal laser microscopy. SLM exhibited aerodynamic diameter proper to be transported up to the alveolar epithelium, negative charged surface able to promote uptake by the macrophages and preserved drug antimicrobial activity. The negligible in vitro release of rifampicin indicated the capacity of the microparticle matrix to entrap the drug preventing its spreading over the lung fluid. In vitro studies on J774 cell lines demonstrated SLM non-cytotoxicity and ability to be taken up by cell cytoplasm. The microparticulate carrier, showing features suitable for the inhaled therapy and for inducing endocytosis by alveolar macrophages, could be considered promising in a perspective of an efficacious TB inhaled therapy by means of a Dry Powder Inhaler device.

The mimicking of physiological conditions is crucial for the success of accurate in vitro studies. For inhaled nanoparticles, which are designed for being deposited on alveolar epithelium and taken up by macrophages, it is relevant to investigate the interactions with pulmonary surfactant lining alveoli. As a matter of fact, the formation of a lipid corona layer around the nanoparticles could modulate the cell internalization and the fate of the transported drugs. Based on this concept, the present research focused on the interactions between pulmonary surfactant and Solid Lipid Nanoparticle assemblies (SLNas), loaded with rifampicin, an anti-tuberculosis drug. SLNas were functionalized with a synthesized mannosylated surfactant, both alone and in a blend with sodium taurocholate, to achieve an active targeting to mannose receptors present on alveolar macrophages (AM). Physico-chemical properties of the mannosylated SLNas satisfied the requirements relative to suitable respirability, drug payload, and AM active targeting. Our studies have shown that a lipid corona is formed around SLNas in the presence of Curosurf, a commercial substitute of the natural pulmonary surfactant. The lipid corona promoted an additional resistance to the drug diffusion for SLNas functionalized with the mannosylated surfactant and this improved drug retention within SLNas before AM phagocytosis takes place. Moreover, lipid corona formation did not modify the role of nanoparticle mannosylation towards the specific receptors on MH-S cell membrane.

Three hydrophilic model drugs with different characteristics and molecular weights, namely protamine sulphate, diclofenac sodium and N 6 -Cyclopentyladenosine (CPA), were nano-encapsulated in poly( d , l -lactide-co-glycolide) (PLGA) using a novel “in-oil nanoprecipitation” method recently developed for the purpose. Although the same settings were used for all three model drugs, the drug loading efficiency was greatly dependent on their chemical–physical characteristics, being considerably higher for protamine (roughly 93%), intermediate for diclofenac (roughly 50%), and very low for CPA (roughly 7%). The resulting particle size and drug release rates were also strictly model-drug dependent. In the attempt to improve the characteristics of the CPA-loaded nanoparticles, the respective effects of adding an excipient (lauric acid) and substituting PLGA with poly( d , l -lactide) polymer (PLA) were investigated by measuring in vitro drug release and drug degradation kinetics in human whole blood. The results indicate that the proposed method seems promising for the nanoencapsulation of hydrophilic drugs in hydrophobic polymers, and easily modifiable to suit molecules that are difficult to incorporate into a polymeric matrix.

For direct intramacrophagic antitubercular therapy, pulmonary administration through Dry Powder Inhaler (DPI) devices is a reasonable option. For the achievement of efficacious aerosolisation, rifampicin-loaded Solid Lipid Nanoparticle assemblies (SLNas) were developed using the melt emulsifying technique followed by freeze-drying. Indeed, this drying method can cause freezing or drying stresses compromising powder respirability. It is the aim of this research to offer novel information regarding pre-freezing variables. These included type and concentration of cryoprotectants, pre-freezing temperature, and nanoparticle concentration in the suspension. In particular, the effects of such variables were observed at two main levels. First of all, on SLNas characteristics - i.e., size, polydispersity index, zeta-potential, circularity, density, and drug loading. Secondly, on powder respirability, taking into account aerodynamic diameter, emitted dose, and respirable fraction. Considering the complexity of the factors involved in a successful respirable powder, a Design of Experiments (DoE) approach was adopted as a statistical tool for evaluating the effect of pre-freezing conditions. Interestingly, the most favourable impact on powder respirability was exerted by quick-freezing combined with a certain grade of sample dilution before the pre-freezing step without the use of cryoprotectants. In such conditions, a very high SLNas respirable fraction (>50%) was achieved, along with acceptable yields in the final dry powder as well as a reduction of powder mass to be introduced into DPI capsules with benefits in terms of administered drug dose feasibility.

Purification processes performed on natural clays to select specific clay minerals are complex and expensive and can lead to over-exploitation of some deposits. The present study aimed to examine physicochemical (mineralogy, morphology, size, surface charge, chemical composition, cation exchange capacity [CEC], and pH) and hydration (swelling, wettability, water sorption, and rheological behavior) properties of three native clays from Italian deposits for potential pharmaceutical and cosmetic uses due to the presence of phyllosilicate minerals. Particular emphasis was placed on energy dispersive X-ray (EDX) microanalysis coupled with the ‘cesium method’ to assay clay elemental composition and CEC. One bentonite of volcanic origin (BNT) and two kaolins, one of hydrothermal origin (K-H) and another of lacustrine-fluvial origin (K-L), were evaluated in comparison with a commercial, purified bentonite. The CEC assay revealed the complete substitution of exchangeable cations (Na+ and Ca2+) by Cs+ in BNT samples and CEC values consistent with those of typical smectites (100.64 ± 7.33 meq/100 g). For kaolins, partial substitution of Na+ cations occurred only in the K-L samples because of the interstratified mineral component which has small CEC values (11.13 ± 5.46 meq/100 g for the K-H sample and 14.75 ± 6.58 meq/100 g for the K-L sample). The degree of isomorphous substitution of Al3+ by Mg2+ affected the hydration properties of BNT in terms of swelling, water sorption, and rheology, whereas both of the poorly expandable kaolins exhibited significant water-adsorption properties. The EDX microanalysis has proved to be of considerable interest in terms of providing more information about clay properties in comparison with other commonly used methods and to identify the role played by both chemical and mineralogical composition of natural clays for their appropriate use in pharmaceutical and cosmetic fields.

Nanotechnology is a fascinating world that has provided and still provides sensational developments in many fields such as in pharmaceutics for diagnosis or drug and gene delivery to cells, tissues or organs. With regard to the latter, cell uptake of nanostructures (generally 1-100 nm) is usually much greater than that of microparticles in the range of 1-10 μm. Although the term “nano” remains of high impact, not always the nanosize is preferable to a larger size. One of these cases is represented by the inhalation of drugs transported within particulate carrier in order to reach the Alveolar macrophages (AM) and eradicate surviving intracellular bacteria in pathologies such as tuberculosis, HIV, S. pneumoniae and S. aureus infections.

Background/Aim: The aim of this study was to evaluate emulsions containing a penetration enhancer, lipid nanoparticles (LNs) or colloidal silica as systems to improve the topical delivery of the flavonoid quercetin. Methods: The skin penetration of quercetin was investigated in vivo on human volunteers by tape stripping. Quercetin-loaded LNs were prepared using hot high-pressure homogenization and characterized by means of dynamic light scattering and release studies. The location of the silica nanoparticles in the skin was determined by inductively coupled plasma mass spectrometry assay of silicon in the stratum corneum strips. Results and Conclusions: The penetration enhancer diethylene glycol monoethyl ether did not produce any significant increase in the fraction of the applied quercetin dose permeated in vivo into human stratum corneum (17.1 ± 3.2%) compared to the control emulsion (18.1 ± 2.3%). A greater but statistically nonsignificant accumulation of the flavonoid in the human horny layer (21.2 ± 2.9% of the applied dose) was measured following topical application of quercetin-loaded LNs (mean particle size: 527 nm). On the other hand, the addition of colloidal silica (average particle diameter: 486 nm) to the emulsion (2%, w/w) significantly increased the in vivo uptake of quercetin by the human stratum corneum to 26.7 ± 4.1% of the applied dose, the enhancing effect on permeation being more marked in the deepest horny layer strips. The measured in vivo skin penetration profile of colloidal silica showed that silica particles diffused down to the intermediate region of the human horny layer and hence could act as carrier for quercetin.

Background: The ability to efficiently cross cellular barriers and accomplish high-level transgene expression is a critical challenge to broad application of nonviral vectors, such as cationic solid lipid nanoparticles (SLN). Aims: This study aims to design and characterize in vitro multicomposite SLN as a novel platform for pDNA delivery. Results/Discussion: The distribution of each component (stearic acid, stearylamine, phosphatidylcholine, cholesterol, protamine and Pluronic F68) in the SLN matrix was studied by electron spectroscopy for chemical analysis and NMR in order to establish its influence on SLN cytotoxicity and transfection efficiency. Multicomposite SLN mediated the expression of enhanced green fluorescent protein in a way comparable with the positive control, but inducing a lower cytotoxicity. Moreover, the carrier exhibited the ability to enter the nucleoli, probably as a result of the synergic action of the nuclear localization signal of protamine and the flexibility of the lipid matrix owing to the phosphatidylcholine. Conclusion: The multicomposite SLN showed good transfection efficiency and negligible cytotoxicity, both crucial factors for an efficient gene-delivery system. Considering the fact that nucleoli have emerged in recent years as important targets in many fields, this novel carrier could have significant future therapy involvements whenever there is a requirement to overcome subcellular barriers. However, further work needs to be carried out in order to fully characterize the formulation, to elucidate where alternative colloidal structures might exist and play a role in obtaining the results presented.

Polysaccharide microparticles for the oral administration of gentamicin were designed in order to obtain an increased drug absorption by means of microparticle transport across the intestinal epithelia. Alginate/chitosan microparticles with a size of ~2 μm were developed by spray-drying a water solution containing the drug complexed with the polyanionic alginate and subsequent alginate cross-linking process by calcium ions and chitosan. The pre-formulation study, performed by changing the concentration of both cross-linkers, led to the selection of the most suitable formulation which was assayed for its capacity to be translocated across intestinal epithelia, via both M cells contained in Follicle Associated Epithelium (FAE) of Peyer's patches and enterocytes of the mucosal epithelium. An ex vivo perfusion technique of rabbit and rat intestinal tissues containing Peyer's patches combined with an in vitro method by using Caco-2 cell monolayers demonstrated the microparticulate carrier ability to be taken up by both M cells and enterocytes. However, only the endocytosis by M cells appeared to provide the microparticle transport from the epithelium toward deeper sub-epithelial regions.

Oral administration of the nonsteroidal anti-estrogen tamoxifen (TMX) is the treatment of choice for metastatic estrogen receptor-positive breast cancer. With the aim to improve TMX oral bioavailability and decrease its side effects, crosslinked alginate microparticles for the targeting to the lymphatic system by Peyer's patch (PP) uptake were developed and in vitro characterized. TMX was molecularly dispersed inside the microparticles and an electrostatic interaction involving the TMX tertiary amine was detected by rheological and FT-IR assays. Microparticles showed a size less than 3 μm, then suitability to be taken up by M cells in PP and a positive surface charge. Moreover, TMX loading level as well as in vitro release behaviour was affected by the polymer network connected with the mannuronic/guluronic ratio of the alginate chains.

Fluorescent calcium alginate/chitosan microparticles, prepared using a spray-drying technique followed by crosslinking reactions with calcium ions and chitosan, were assayed in-vivo for polymyxin B (PMB) oral toxicity, uptake by Peyer's patches and PMB oral absorption. A single PMB dose (300 mg kg−1), loaded in microparticles or dissolved in water, was administered to rats by oral gavage under fasted and fed conditions. By monitoring incidence of mortality, animal behaviour, clinical signs and abnormality in several organs, PMB in water solution was found lethal at a dose lower than the LD50 (790 mg kg−1) in the fasted state and toxic for the gastrointestinal tract in the fed state. However, no signs of acute toxicity at the level of the gastrointestinal tract were observed when animals were administered PMB loaded in microparticles under fasted and fed conditions. A lower PMB dose (125 mg kg−1), loaded in microparticles or dissolved in water, was given to rats in a fed state to determine PMB levels in Peyer's patches, urine and serum as well as to detect the loaded microparticles inside Peyer's patches for three days after dosing. Abnormalities were observed at gut level only when PMB was dosed in a water solution. Detectable antibiotic levels in Peyer's patches and urine as well as more constant PMB serum concentrations were provided by dosing PMB loaded in microparticles. Therefore, the use of alginate/chitosan microparticles to target the lymphatic system could improve safety when administering PMB orally.

In this study, lipid microparticles (LMs) uncoated or coated with chitosan, and containing the antioxidant polyphenol, resveratrol were developed in order to enhance its in vivo skin permeation. The LMs loaded with resveratrol were prepared by melt emulsification and sonication, using tristearin as lipidic material and hydrogenated phosphatidylcholine as the surfactant. Two different methods were examined for the coating of the LMs: chitosan addition during LM preparation or treatment of already formed LMs with a chitosan solution. The latter method achieved a better modulation of the in vitro release of resveratrol and hence was used for subsequent studies. The resveratrol loading and mean diameter of the LMs were 4.1 ± 0.3% (w/w) and 5.7 μm and 3.8 ± 0.2 % (w/w) and 6.1 μm for the uncoated and the chitosan-coated LMs, respectively. Chitosan coating changed the LM surface charge, from a negative zeta potential value (-17.8 ± 4.8 mV) for the uncoated particles, to a higher positive values (+64.2 ± 4.4 mV) for the chitosan-coated ones. Creams containing resveratrol free, encapsulated in the uncoated or chitosan-coated LMs were applied to the forearm of human volunteers and the penetration of the polyphenol in the stratum corneum was investigated in vivo by the tape stripping technique. Uncoated LMs did not produce any significant increase in the fraction of the applied resveratrol dose diffused in the stratum corneum (32.8 ± 8.9 %) compared to the control cream containing the non-encapsulated polyphenol (26.2 ± 5.6 % of the applied dose). On the other hand, application of the cream containing the chitosan-coated LMs produced a significant enhancement in the in vivo permeation of resveratrol to 49.3 ± 5.9% of the applied dose, the effect being more marked in the upper region of the horny layer. The observed improvement in the human stratum corneum penetration of resveratrol achieved by the LMs coated with chitosan should favour the efficiency of its topical application.

Recently, octapeptide LSCQLYQR (LRp), reducing growth of cis-platinum (cDDP) resistant ovarian carcinoma cells by inhibiting the monomer-monomer interface of the human enzyme thymidylate synthase, has been identified. As the peptide is not able to cross the cell membrane it requires an appropriate delivery system. In this work the application of SLNs, biocompatible and efficient tools for the intracellular drug transport, applied especially for lipophilic drugs, was exploited for the delivery of the hydrophilic peptide LRp. SLNs formulated in the absence/presence of small amount of squalene showed dimensions below 150 nm, negative zeta potential and good stability to the freeze-drying process. Even though the particles formulated with squalene exhibited a less ordered crystal lattice and a lower surface hydrophobicity, a rapid drug release from these nanocarriers occurred as a result of the relevant expulsion of the drug from the lipid core during lipid crystallization. On the contrary, SLNs formulated in the absence of squalene were able to incorporate more stably the peptide showing considerable cytotoxic effect on cDDP resistant C13* ovarian carcinoma cell line at concentration 50 times lower than that used previously with a marketed delivery system. From the cell cycle analysis by the propidium iodide test in SLNs-peptide treated cancer cells an increase of apoptosis percentage was observed, indicating that SLNs were able to carry efficiently the peptide until its enzymatic target.

The paper aims to explore the potential benefits provided by an organically modified montmorillonite (nanoclay) in the problematic management of the Helicobacter pylori gastric infection that is one of the most prevalent infectious diseases worldwide. Two nanoclay samples were produced by the intercalation of tetracycline (TC) into the interlayer of montmorillonite (MM) under two different pH reaction conditions (pH 3.0 and 8.7). MM/TC nanoclays were characterized by EDX, XRD, FTIR, DSC, drug adsorption extent, in vitro mucoadhesiveness and desorption in simulated gastric media. The reaction between MM and TC led to a complete MM cation (Na(+) and Ca(2+)) exchange process, an increase of MM characteristic interlayer spacing as well as an involvement of NHR3(+) group of TC, regardless of the reaction pH value. However, MM/TC nanoclay obtained under alkaline conditions provided a lower TC adsorption as well as a drug fraction weakly linked to MM in comparison with the nanoclay obtained in acidic conditions. Both the nanoclays exhibited good mucoadhesion properties to porcine mucin and TC desorption occurring mainly via a cation exchange process by H(+) ions. Based on the results obtained, TC intercalation into MM nanoplatelets could represent a potential advantageous approach allowing the antibiotic to distribute homogeneously on the gastric mucosa, diffuse through the gastric mucus layer and achieve the microorganism localization.

The effect of lipid microparticle carrier systems on the light-induced degradation of melatonin was investigated. Microspheres loaded with melatonin were prepared using tristearin or tripalmitin as the lipid material and hydrogenated phosphatidylcholine or polysorbate 60 as the emulsifier. The obtained lipid microspheres were characterized by scanning-electron microscopy and differential scanning calorimetry. Free or microencapsulated melatonin was incorporated in a model cream formulation (oil-in-water emulsion) and irradiated with a solar simulator. The extent of photodegradation was measured by high-performance liquid chromatography. The photolysis experiments demonstrated that the light-induced decomposition of melatonin was markedly decreased by encapsulation into lipid microspheres based on tristearin and phosphatidylcholine (the extent of degradation was 19.6% for unencapsulated melatonin compared to 5.6% for the melatonin-loaded microparticles). Therefore, incorporation in lipid microparticles can be considered an effective system to enhance the photostability of melatonin.

An air compartment multiple-unit system composed of a calcium alginate core separated by an air compartment from a calcium alginate/PVA membrane has shown excellent in vivo buoyancy ability and prolonged gastric residence time (GRT) in previous published works. In the present investigation, the floating system was loaded with riboflavin-5’-phosphate (FMN), mainly absorbed in the upper region of the small intestine, assayed in humans for riboflavin pharmacokinetics under different feeding conditions and compared with a non-floating system. The cumulative urinary excretion within 24 h resulted in generally higher by dosing FMN through the floating system under all feeding protocols. The highest values were observed when meals followed dosing (succession of meals protocol), though there was a certain variability between the subjects; the highest reproducibility among the subjects was achieved with dosing of the drug after a substantial meal (lunch protocol).

Oral administration of peptide and protein drugs requires their protection from the acidic and enzymatic degradation in the gastro-intestinal environment and their targeting to the absorption zone. For this purpose, an alginate microsystem, as a carrier of bovine serum albumin (BSA), as a model protein, was developed using a spray-drying technique. A hardening process with Ca2+ and chitosan (CS) provided a system with resistance to the gastro-intestinal barriers and of appropriate size for targeting to the Peyer's patches. The present work aims to evaluate the effects of the ratio of sodium alginate (Na-A) and BSA as well as the pH of the crosslinking medium on the microsystem properties. Microparticle morphological and dimensional characteristics did not change significantly with the formulation variables. BSA loading at a pH value less than the protein isoelectric point (pI) was higher than that at a pH similar to the pI owing to an electrostatic interaction between the charged protein and the polyanionic alginate. The maximum encapsulation efficiency was obtained at the highest Na-A/BSA ratio. Protein release in a simulated gastro-intestinal fluid was not affected by the preparative variables, but was controlled by the pH-dependent nature of the polymer material. Polyacrylamide gel electrophoresis (PAGE) demonstrated the stability of the protein to both the preparative conditions and the gastro-intestinal pH values.

Our previous results demonstrated that a prodrug obtained by the conjugation of the antiretroviral drug zidovudine (AZT) with ursodeoxycholic acid (UDCA) represents a potential carrier for AZT in the central nervous system, thus possibly increasing AZT efficiency as an anti-HIV drug. Based on these results and in order to enhance AZT brain targeting, the present study focuses on solid lipid microparticles (SLMs) as a carrier system for the nasal administration of UDCA-AZT prodrug. SLMs were produced by the hot emulsion technique, using tristearin and stearic acid as lipidic carriers, whose mean diameters were 16 and 7 μm, respectively. SLMs were of spherical shape, and their prodrug loading was 0.57 ± 0.03% (w/w, tristearin based) and 1.84 ± 0.02% (w/w, stearic acid based). The tristearin SLMs were able to control the prodrug release, whereas the stearic acid SLMs induced a significant increase of the dissolution rate of the free prodrug. The free prodrug was rapidly hydrolyzed in rat liver homogenates with a half-life of 2.7 ± 0.14 min (process completed within 30 min). The tristearin SLMs markedly enhanced the stability of the prodrug (75% of the prodrug still present after 30 min), whereas the stabilization effect of the stearic acid SLMs was lower (14% of the prodrug still present after 30 min). No AZT and UDCA-AZT were detected in the rat cerebrospinal fluid (CSF) after an intravenous prodrug administration (200 μg). Conversely, the nasal administration of stearic acid based SLMs induced the uptake of the prodrug in the CSF, demonstrating the existence of a direct nose-CNS pathway. In the presence of chitosan, the CSF prodrug uptake increased six times, up to 1.5 μg/mL within 150 min after nasal administration. The loaded SLMs appear therefore as a promising nasal formulation for selective zidovudine brain uptake.

Lipid-based particulate delivery systems have been extensively investigated in the last decade for both pharmaceutical and cosmetic skin application although their translocation across the skin is not yet clarified. The aim of this paper was to investigate on humans the ability of solid lipid nanoparticles (SLN) and solid lipid microparticles (SLM) to penetrate the outermost stratum corneum (SC) and to be modified upon contact with the cutaneous components by using the Tape Stripping Test coupled with the energy dispersive X-ray (EDX) analysis. SLN and SLM were prepared by the melt emulsification technique and loaded with nanosized titanium dioxide (TiO 2 ) to become identifiable by means of X-ray emission. Following human skin application, the translocation of the particulate systems was monitored by the analysis of twelve repetitive stripped tapes using non-encapsulated metal dioxide as the control. Intact SLN as well as non-encapsulated TiO 2 were recorded along the largest SC openings until the 12th stripped tape suggesting the intercluster region as their main pathway. Evidences of a concurrent biodegradation process of the lipid matrix, as the result of SLN interaction with the lipid packing between the corneocyte clusters, were found in the deepest SC layers considered. On the contrary, SLM were retained on the skin surface without undergoing biodegradation so preventing the leaching and the subsequent SC translocation of the loaded TiO 2 .

Coated beads were prepared by soaking in sodium alginate solutions spherical matrices (beads) of carboxymethylcellulose crosslinked with aluminum chloride (AlCl3) and loaded with ambroxol hydrochloride as a model drug. The residual amount of the crosslinker induced an interfacial crosslinking reaction of the sodium alginate. Therefore, an insoluble, smooth and uniform in thickness coat was formed around the beads. As the coating time increased, the coat thickness increased until1 AlCl3 was present inside the beads. The rate of drug release from the coated beads was slower than that from the uncoated beads and decreased with the increase in coating time. Moreover, a constant rate phase, subsequent a burst period for the samples obtained with the highest coating times, was achieved. The dynamic swelling analysis allowed to exclude the influence of the polymer relaxation on the release process which appeared to be controlled by the alginate coat.

Several advanced in vitro and in vivo studies have proved the broad potential of cationic solid lipid nanoparticles (SLN) as nonviral vectors. However, a few data are available about the correlation between lipid component of the SLN structure and in vitro performance in terms of cell tolerance and transfection efficiency on different cell lines. In this paper SLN were prepared using stearic acid as main lipid component, stearylamine as cationic agent and protamine as transfection promoter and adding phosphatidylcholine (PC), cholesterol (Chol) or both to obtain three different multicomponent SLN (SLN-PC, SLN-Chol and SLN-PC-Chol, respectively). Cytotoxicity and transfection efficiency of the obtained SLN:pDNA complexes were evaluated on three different immortalized cell lines: COS-I (African green monkey kidney cell line), HepG2 (human hepatocellular liver carcinoma cell line) and Na1300 (murine neuroblastoma cell line). Samples were characterized for the exact quantitative composition, particle size, morphology, zeta potential and pDNA binding ability. All the three SLN samples were about 250-300 nm in size with a positive zeta potential, whereas SLN:pDNA complexes were about 300-400 nm in size with a less positive zeta potential, depending on the SLN composition. Concerning the cell tolerance, the three samples showed a level of cytotoxicity lower than that of the positive control polyethylenimine (PEI), regardless of the cell lines. The best transfection performance was observed for SLN-PC-Chol on COS-I cells while a transfection level lower than PEI was observed on HepG2 cells, regardless the SLN composition. On Na1300 cells, SLN-Chol showed a double efficiency with respect to PEI. Comparing these results to those obtained with the same kind of SLN without PC and/or Chol, it is possible to conclude that the addition of Chol and/or PC to the composition of cationic SLN modify the cell tolerance and the transfection efficiency of the gene vector in a manner strictly dependent on the cell type and the internalization pathways.

Cationic solid lipid nanoparticles (SLN) have been recently proposed as non-viral vectors in systemic gene therapy. The aim of this study was to evaluate the effect of the protamine amount used as the transfection promoter in SLN-mediated gene delivery. Three protamine-SLN samples (Pro25, Pro100, and Pro200) prepared by adding increasing amounts of protamine were characterized for their size, zeta potential, and protamine loading level. The samples were evaluated for pDNA complexation ability by gel-electrophoresis analysis and for cytotoxicity and transfection efficiency by using different cell lines (COS-I, HepG2, and Na1300). The size of SLN was ~230 nm and only Pro200 showed few particle aggregates. Unlike the Pro25 sample with the lowest protamine loading level, the others SLN samples (Pro100 and Pro200) exhibited a good ability in complexing pDNA. A cell-line dependent cytotoxicity lower than that of the positive control PEI (polyethilenimmine) was observed for all the SLN. Among these, only Pro100, having an intermediate amount of protamine, appeared able to promote pDNA cell transfer, especially in a neuronal cell line (Na1300). In conclusion, the amount of protamine as the transfection promoter in SLN affects not only the gene delivery ability of SLN but also their capacity to transfer genes efficiently to specific cell types.

Lipid microparticles loaded with the complex between hydroxypropyl-β-cyclodextrin (HP-β-CD) and the sunscreen agent, butyl methoxydibenzoylmethane (BMDBM) were evaluated for their effect on the UV filter percutaneous penetration. The microparticles were prepared by the melt emulsification technique using tristearin as lipidic material and hydrogenate phosphatidylcholine as the surfactant. Human skin penetration was investigated in vivo by the tape stripping technique, a minimal invasive procedure based on the progressive removal of the upper cutaneous layers (stratum corneum) with adhesive tape strips. The amount of sunscreen fixed to each strip was determined by HPLC after solvent extraction. The recovery of the UV filter from spiked adhesive tapes was >94.4% and the precision of the method was better than 7.6% relative standard deviation. Non-encapsulated BMDBM, its complex with HP-β-CD, the lipid microparticles loaded with the sunscreen alone or the BMDBM/HP-β-CD complex were introduced into oil-in-water emulsions and applied to human volunteers. Compared to the cream with the non-encapsulated sunscreen agent (percentage of the applied dose penetrated, 9.7% ± 2.5), the amount of BMDBM diffusing into the stratum corneum was increased by the formulations containing the BMDBM/HP-β-CD complex (17.1% ± 3.2 of the applied dose) or the microparticles loaded with BMDBM only (15.1% ± 2.7 of the applied dose). On the contrary, a significant decrease in the level of UV filter penetrated into the stratum corneum was achieved by the cream containing the microencapsulated BMDBM/HP-β-CD complex (percentage of the applied dose penetrated, 6.0% ± 1.5). The reduced BMDBM percutaneous penetration attained by the latter system should enhance the UV filter efficacy and limit potential toxicological risks.

Spherical matrices (beads) of cross-linked carboxymethylcellulose were prepared by the in-liquid curing coating process using AlCl3 as curing agent (cross-linker). The loading process was carried out either by adding the drug to the polymer solutions before the extrusion process or by swelling the crosslinked beads in a drug solution. The energy dispersive X-ray (EDS) analysis showed a homogeneous distribution of both the drug concentration and cross-linking density in the network regardless to the loading procedure. When the loading process was carried out before the extrusion process, a residual amount of AlCl3 remained in the beads. The effects of the residual amount of AlCl3 on the matrix swelling and drug release processes were analyzed.

Alginate/chitosan microparticles with a mean size less than 1 microm, designed in a previous work for the targeting of polymyxin B to M-cells and, then, to the lymphatic system, were assayed for transport ability by enterocytes. Caco-2 cell monolayer model, combined with confocal microscopy, showed that microparticles were endocytosed by the cells through an energy-dependent process, being the process saturable at 6 h incubation. Furthermore, microparticles maintained the biological activity of the antibiotic and decreased the antibiotic cytotoxicity against Vero cell cultures. Therefore, simultaneous pathways via both M-cells and enterocytes could be proposed for such a microparticulate carrier.

Microparticles are used for controlled drug delivery. With the aim of improving both bioavailability and tamoxifen selective toxicity, the activity of tamoxifen embedded in calcium alginate/chitosan microparticles was studied.Tamoxifen alone and embedded in microparticles prepared with sodium alginate from Kelco (62% mannuronic acid and 38% guluronic acid) and from Fluka (30% mannuronic acid and 70% guluronic acid) was added to MCF-7 and Vero cultures and evaluated for antiproliferative activity by the MTT test.The use of Kelco or Fluka alginate resulted in different LD(50) values on Vero and MCF-7 cultures, showing a higher cytotoxicity toward Vero cells treated with tamoxifen embedded in Kelco microparticles (25 microM vs. 48 microM on MCF-7 cells) but a selective toxicity with Fluka microparticles (25 microM and 10 microM on Vero and MCF-7 cells respectively).Microparticle formulation may improve selective toxicity according to the alginate employed: differences in the chemical alginate composition can dramatically change both drug activity and toxicity.

Lipid microparticles (lipospheres) loaded with butyl methoxydibenzoylmethane (BMDBM), a widely used UV-A sunscreen agent, were prepared by melt technique and evaluated for skin permeation both in vivo, by tape stripping method, and in vitro, by a flow-through diffusion chamber. Following in vivo human skin application of an O/W emulsion containing 2% of BMDBM loaded in lipospheres, 15% of the applied sunscreen accumulated in the uppermost layers of the stratum corneum without remarkably modifying the skin permeation of the unencapsulated sunscreen. These results were found to be predicted by an in vitro methodology involving the diffusion of BMDBM through a lipophilized synthetic membrane into a hydrophilic receptor phase, simulating the viable epidermis better than an ethanolic receptor phase.

The objective of this study was to prepare lipid microparticles (LMs) loaded with the sunscreen agent, 4-methylbenzylidene camphor (4-MBC), to achieve decreased skin penetration of this UV filter. The microparticles were produced by the melt dispersion technique using tristearin as lipidic material and hydrogenated phosphatidylcholine as the surfactant. The obtained microparticles were characterized by scanning electron microscopy and differential scanning calorimetry. Release of 4-MBC from the LMs was found to be slower than its dissolution rate. The influence of the LMs' carrier system on percutaneous penetration was evaluated after their introduction in a model topical formulation (emulsion). In-vitro measurements were performed with cellulose acetate membranes in Franz diffusion cells. The 4-MBC release and diffusion was decreased by 66.7–77.3% with the LM formulation, indicating that the retention capacity of the microparticles was maintained after incorporation into the emulsion. In-vivo human skin penetration of 4-MBC was investigated by tape stripping, a technique for selectively removing the upper cutaneous layers. The amount of sunscreen penetrating into the stratum corneum was greater for the emulsion containing non-encapsulated 4-MBC (36.55% of the applied dose) compared with the formulation with the sunscreen-loaded microparticles (24.57% of the applied dose). The differences between the two formulations were statistically significant in the first (2–4) horny layer strips. Moreover, the LMs' effect measured in-vivo was less pronounced than in-vitro. The increased 4-MBC retention on the skin surface achieved by its incorporation in the LMs should enhance its efficacy and reduce the potential toxicological risk associated with skin penetration.

The interaction between the sunscreen agent, 4-methylbenzylidene camphor (4-MBC) and hydrophilic alpha-, beta- and gamma-cyclodextrin derivatives was investigated in water by phase-solubility analysis. Among the studied cyclodextrins, random methyl-beta-cyclodextrin (RM-beta-CD) had the greatest solubilizing activity. The complexation of the sunscreen agent with RM-beta-CD was confirmed by nuclear magnetic resonance spectroscopy and powder X-ray diffractometry. The light-induced decomposition of 4-MBC in emulsion vehicles was markedly decreased by complexation with RM-beta-CD (the extent of degradation, determined by HPLC, was 7.1% for the complex compared to 21.1% for free 4-MBC). The influence of RM-beta-CD on the human skin penetration of the sunscreen was investigated in vivo using the tape stripping method, a useful procedure for selectively removing the outermost cutaneous layers. Considerable quantities (21.2-25.1% of the applied dose) of 4-MBC permeated in the stratum corneum. However, no significant differences in the amounts of UV filter in the 10 first strips of the horny layer were observed between the formulations containing 4-MBC free or complexed with RM-beta-CD. Therefore, RM-beta-CD complexation did not alter the retention of 4-MBC in the superficial layers of the stratum corneum, where its action is more desirable.

The aim of this study was to investigate the incorporation into lipospheres of the complex between hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and the sunscreen agent, butyl methoxydibenzoylmethane (BMDBM) and to examine the influence of this system on the sunscreen photostability. The formation of the inclusion complex was confirmed by thermal analysis and powder X-ray diffraction. Lipid microparticles loaded with free BMDBM or its complex with HP-beta-CD were prepared using tristearin as the lipid material and hydrogenated phosphatidylcholine as the emulsifier. The obtained lipospheres were characterized by scanning electron microscopy and differential scanning calorimetry. The microparticle size (15-40 microm) was not affected by the presence of the complex. Release of BMDBM from the lipospheres was lower when it was incorporated as inclusion complex rather than as free molecule. Unencapsulated BMDBM, its complex with HP-beta-CD, the sunscreen-loaded lipospheres or the lipoparticles containing the BMDBM/HP-beta-CD complex, were introduced into a model cream (oil-in-water emulsion) and irradiated with a solar simulator. The photodegradation studies showed that all the examined systems achieved a significant reduction of the light-induced decomposition of the free sunscreen agent (the BMDBM loss decreased from 28.9 to 17.3-15.2%). However, photolysis experiments performed during 3 months storage of the formulations, demonstrated that the photoprotective properties of the HP-beta-CD complex and of BMDBM alone-loaded lipospheres decreased over time, whereas the microencapsulated HP-beta-CD/BMDBM complex retained its photostabilization efficacy. Therefore, incorporation in lipid microparticles of BMDBM in the cyclodextrin complex form is more effective in enhancing the sunscreen photostability than the complex alone or the liposphere-entrapped free BMDBM.

A crosslinked alginate microparticle system for the targeting to the lymphatic system by Peyer's patches (PP) uptake was designed in order to improve the oral absorption of Polymyxin B (PMB). To verify mucoadhesion and PP uptake, microparticles labelled with fluorescein isothiocyanate (FITC) were prepared by spray-drying technique and crosslinking reactions with calcium ions and chitosan (CS), in vitro characterized and assayed by an ex vivo method. Microparticles showed a size less then 3 microm, an antibiotic loading level of 11.86 +/- 0.70%, w/w, a sustained drug release behaviour in simulated gastro-intestinal (GI) fluids and a preserved biological activity throughout the manufacture. The ex vivo study was performed by a perfusion method on intestinal tracts of just sacrificed adult rats. The recovered samples were analysed by epifluorescence microscope for mucoadhesion and PP uptake and by microbiological analysis for antibiotic activity preservation, providing evidence of mucoadhesion at the level of both PP and non-PP epithelium, uptake by PP and PMB microbiological activity in PP tissue. Furthermore, the study revealed the involvement of transport pathways across villous enterocytes.