14 research outputs found

    The lizard celestial compass detects linearly polarized light in the blue

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    SummaryThe present study first examined whether ruin lizards Podarcis sicula are able to orientate using plane polarized light produced by a LCD screen. Ruin lizards were trained and tested indoors, inside an hexagonal Morris water maze, positioned under the LCD screen producing white polarized light with a single E-vector, which provided an axial cue. White polarized light did not include wavelengths in the UV. Lizards orientated correctly either when tested with E-vector parallel to the training axis or after 90° rotation of the E-vector direction, and thus validating the apparatus. Further experiments examined whether in ruin lizards there is a preferential region of the light spectrum to perceive the E-vector direction of polarized light. For this purpose, lizards reaching learning criteria under white polarized light were subdivided into 4 experimental groups. Each group was respectively tested for orientation under a different spectrum of plane polarized light (named red, green, cyan and blue) with equalized photon flux density. Lizards tested under blue polarized light orientated correctly, whereas lizards tested under red polarized light were completely disoriented. Green polarized light was barely discernible by lizards, and thus insufficient for a correct functioning of their compass. When exposed to cyan polarized light, lizard orientation performances were optimal, indistinguishable from lizards detecting blue polarized light. Overall, the present results demonstrate that perception of linear polarization in the blue is necessary - and sufficient - for a proper functioning of the sky polarization compass of ruin lizards. This may be adaptively important, since detection of polarized light in the blue improves functioning of the polarization compass under cloudy skies, i.e. when the alternative celestial compass based on detection of the sun disk is rendered useless because the sun is obscured by clouds

    The Impact of Lipid Corona on Rifampicin Intramacrophagic Transport Using Inhaled Solid Lipid Nanoparticles Surface-Decorated with a Mannosylated Surfactant

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    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

    Nasal Powders of Morphine Microcrystal Agglomerates.

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    Chimeral agglomerates of microparticles for the administration of caffeine nasal powders.

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    Abstract This study investigated the possibility to use spray drying technique to prepare powders formulations containing caffeine intended for nasal delivery. Spray dried powders containing caffeine and excipients, as filler and shaper agents, were prepared. Powders were investigated for particle size, morphology and delivery properties from Monopowder P®nasal insufflator, assessing the influence of each excipient on microparticles characteristics. The results showed that the excipients strongly affected microparticle properties. Size, shape and agglomeration tendency are relevant characteristics of spray dried nasalpowde

    Anti-inflammatory flurbiprofen nasal powders for nose-to-brain delivery in Alzheimer’s disease

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    Neuroinflammation occurs in the early stages of Alzheimer's disease (AD). Thus, anti-inflammatory drugs in this asymptomatic initial phase could slow down AD progression, provided they enter the brain. Direct nose-to-brain drug transport occurs along olfactory or trigeminal nerves, bypassing the blood-brain barrier. Nasal administration may enable the drug to access the brain. Here, flurbiprofen powders for nose-to-brain drug transport in early AD-related neuroinflammation were studied. Their target product profile contemplates drug powder deposition in the nasal cavity, prompt dissolution in the mucosal fluid and attainment of saturation concentration to maximise diffusion in the tissue. Aiming to increase drug disposition into brain, poorly soluble flurbiprofen requires the construction of nasal powder microparticles actively deposited in nose for prompt drug release. Two groups of powders were formulated, composed of flurbiprofen acid or flurbiprofen sodium salt. Two spray dryer apparatuses, differing for spray and drying mechanisms, and particle collection, were applied to impact on the characteristics of the microparticulate powders. Flurbiprofen sodium nasal powders disclosed prompt dissolution and fast ex vivo transport across rabbit nasal mucosa, superior to the acid form, in particular when the powder was prepared using the Nano B-90 spray dryer at the lowest drying air temperature

    Nasal powders of thalidomide for local treatment of nose bleeding in persons affected by hereditary hemorrhagic telangiectasia

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    In this work nasal powder formulations of thalidomide were designed and studied to be used by persons affected by hereditary hemorrhagic telangiectasia as a complementary anti-epistaxis therapy, with the goal of sustaining the effect obtained with thalidomide oral treatment after its discontinuation for adverse effects. Three nasal powders were prepared using as carriers β-CD or its more hydrophilic derivatives such as hydropropyl-β-CD and sulphobutylether-β-CD and tested with respect to technological and biopharmaceutical features after emission with active and passive nasal powder devices. For all formulated powders, improved dissolution rate was found compared to that of the raw material, making thalidomide promptly available in the nasal environment at a concentration favouring an accumulation in the mucosa. The very limited transmucosal transport measured in vitro suggests a low likelihood of significant systemic absorption. The topical action on bleeding could benefit from the poor absorption and from the fact that about 2–3% of the thalidomide applied on the nasal mucosa was accumulated within the tissue, particularly with the β-CD nasal powder

    Novel engineered lipid-based nanoparticles for pulmonary tuberculosis inhalation therapy

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    Priorities to achieve the WHO goal of ending tuberculosis (TB) epidemic by 2030 include new drug treatments to simplify and shorter conventional drug regimens. TB is caused by Mycobacterium tuberculosis residing and surviving inside alveolar macrophages (AM). Considering that 75-80% of cases of infection remain localized in the lungs, the easiest and most successful therapy could involve the inhalation route offering benefits in terms of patient’s autonomy and compliance, by-passing hepatic metabolism, reducing dose amount, dose frequency, and treatment duration, thus minimising the risk of drug-resistant mutants, toxicity, and side effects. Inhalable powder formulations of repurposed drugs entail engineering techniques such as micro- or nanoparticulate carriers enabling drug emission by Dry Powder Inhaler devices, deposition onto alveolar epithelia, and transport into AM. Within this context, Solid Lipid Nanoparticle assemblies (SLNas) loaded with rifampicin, a clinically useful anti-TB drug, were produced by processing accepted excipients for DPI formulations through an optimized methodology that avoids organic solvents and is suitable for a large-scale production. The prototypes were functionalized by means of newly synthesized AM receptor-specific targeting agents as the ligands anchored on SLNas surface without chemical reactions. In vitro and in vivo preclinical studies highlighted functionalized SLNas with adequate respirability performance, safety, AM internalization ability, and mice lung deposition in an encouraging perspective of a potential efficacious pulmonary TB therapy. This research was supported by a grant on the project “FAR interdisciplinare 2017” from the University of Modena and Reggio Emilia, Modena, Italy (PI Prof. Luca Costantino
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