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Worldwide, colon cancer (CC) represents the fourth most common type of cancer and the fifth major cause of cancer-associated deaths. Surgical resection is considered the standard therapeutic choice for CC in early stages. However, in latter stages of the disease, adjuvant chemotherapy is essential for an appropriate management of this pathology. Metal-based complexes displaying cytotoxic properties towards tumor cells emerge as potential chemotherapeutic options. One metallodrug, oxaliplatin, was already approved for clinical use, playing an important role in the treatment of CC patients. Unfortunately, most of the newly designed metal-based complexes exhibit lack of selectivity against cancer cells, low solubility and permeability, high dose-limiting toxicity, and emergence of resistances. Nanodelivery systems enable the incorporation of metallodrugs at adequate payloads, solving the above-referred drawbacks. Moreover, drug delivery systems, depending on their physicochemical properties, are able to release the incorporated material preferentially at affected tissues/organs, enhancing the therapeutic activity in vivo, with concomitant fewer side effects. In this review, the general features and therapeutic management of CC will be addressed, with a special focus on preclinical or clinical studies using metal-based compounds. Furthermore, the use of different nanodelivery systems will also be described as tools to potentiate the therapeutic index of metallodrugs for the management of CC.

Hyaluronic acid (HA) is commonly used through intra-articular administration for viscosupplementation in osteoarthritis and other disorders. HA is generally supplied as an injection commonly reported as painful, with strong limitations after treatment. In this study, an alternative delivery system was constructed based on HA hydrogel and poly(lactic-co-glycolic acid) (PLGA) particles with oleic acid. Development studies included the determination of particle toxicity, hemolytic activity, in vitro and in vivo anti-inflammatory activity using macrophages and a murine model, respectively. This study showed that empty PLGA particles presented a mean size of 373 nm, while particles containing HA and oleic acid showed a marked particle size increase. The HA association efficiency was of 73.6% and 86.2% for PLGA particles without and with oleic acid, respectively. The in vitro HA release from PLGA particles revealed a sustained profile. Particles showed a good in vitro cell compatibility and the risk of hemolysis was less < 1%, ensuring their safety. The in vivo anti-inflammatory study showed a higher inhibition for HA-loaded PLGA particles when compared to HA solution (78% versus 60%) and they were not different from the positive control, clearly suggesting that this formulation may be a promising alternative to the current HA commercial dosage form. iMed.ULisboa [UID/DTP/04138/2013] CESAM [UID/AMB/50017/2019] FCT/MEC through Portuguese funds FEDER, within the PT2020 Partnership Agreement Compete 2020

Sambucus nigra L. (S. nigra) is a shrub widespread in Europe and western Asia, traditionally used in medicine, that has become popular in recent years as a potential source of a wide range of interesting bioactive compounds. The aim of the present work was to develop a topical S. nigra extract formulation based on ethosomes and thus to support its health claims with scientific evidence. S. nigra extract was prepared by an ultrasound-assisted method and then included in ethosomes. The ethosomes were analyzed in terms of their size, stability over time, morphology, entrapment capacity (EC), extract release profile, stability over time and several biological activities. The prepared ethosomes were indicated to be well defined, presenting sizes around 600 nm. The extract entrapment capacity in ethosomes was 73.9 ± 24.8%, with an interesting slow extract release profile over 24 h. The extract-loaded ethosomes presented collagenase inhibition activity and a very good skin compatibility after human application. This study demonstrates the potential use of S. nigra extract incorporated in ethosomes as a potential cosmeceutical ingredient and on further studies should be performed to better understand the impact of S. nigra compounds on skin care over the time.

Insulin is a peptide hormone with many physiological functions, besides its use in diabetes treatment. An important role of insulin is related to the wound healing process—however, insulin itself is too sensitive to the external environment requiring the protective of a nanocarrier. Polymer-based nanoparticles can protect, deliver, and retain the protein in the target area. This study aims to produce and characterize a topical treatment for wound healing consisting of insulin-loaded poly-DL-lactide/glycolide (PLGA) nanoparticles. Insulin-loaded nanoparticles present a mean size of approximately 500 nm and neutral surface charge. Spherical shaped nanoparticles are observed by scanning electron microscopy and confirmed by atomic force microscopy. SDS-PAGE and circular dichroism analysis demonstrated that insulin preserved its integrity and secondary structure after the encapsulation process. In vitro release studies suggested a controlled release profile. Safety of the formulation was confirmed using cell lines, and cell viability was concentration and time-dependent. Preliminary safety in vivo assays also revealed promising results.

Antimicrobial drugs are key tools to prevent and treat bacterial infections. Despite the early success of antibiotics, the current treatment of bacterial infections faces serious challenges due to the emergence and spread of resistant bacteria. Moreover, the decline of research and private investment in new antibiotics further aggravates this antibiotic crisis era. Overcoming the complexity of antimicrobial resistance must go beyond the search of new classes of antibiotics and include the development of alternative solutions. The evolution of nanomedicine has allowed the design of new drug delivery systems with improved therapeutic index for the incorporated compounds. One of the most promising strategies is their association to lipid-based delivery (nano)systems. A drug’s encapsulation in liposomes has been demonstrated to increase its accumulation at the infection site, minimizing drug toxicity and protecting the antibiotic from peripheral degradation. In addition, liposomes may be designed to fuse with bacterial cells, holding the potential to overcome antimicrobial resistance and biofilm formation and constituting a promising solution for the treatment of potential fatal multidrug-resistant bacterial infections, such as methicillin resistant Staphylococcus aureus. In this review, we aim to address the applicability of antibiotic encapsulated liposomes as an effective therapeutic strategy for bacterial infections.

Anaplastic thyroid carcinoma (ATC) is a very rare subtype of thyroid carcinoma and one of the most lethal malignancies. Poor prognosis is mainly associated with its undifferentiated nature, inoperability, and failing to respond to the typically used therapies for thyroid cancer. Photothermal Therapy (PTT) entails using light to increase tissues’ temperature, leading to hyperthermia-mediated cell death. Tumours are more susceptible to heat as they are unable to dissipate it. By using functionalized gold nanoparticles (AuNPs) that transform light energy into heat, it is possible to target the heat to the tumour. This study aims to formulate ATC-targeted AuNPs able to convert near-infrared light into heat, for PTT of ATC. Different AuNPs were synthetized and coated. Size, morphology, and surface plasmon resonances band were determined. The optimized coated-AuNPs were then functionalized with ligands to assess ATC’s specificity. Safety, efficacy, and selectivity were assessed in vitro. The formulations were deemed safe when not irradiated (>70% cell viability) and selective for ATC. However, when irradiated, holo-transferrin-AuNPs were the most cytotoxic (22% of cell viability). The biodistribution and safety of this formulation was assessed in vivo. Overall, this novel formulation appears to be a highly promising approach to evaluate in a very near future., Authors gratefully acknowledge Fundação para a Ciência e a Tecnologia (FCT) through projects UIDB/00645/2020, UIDB/04138/2020, PTDC/MED-QUI/31721/2017, UIDP/04138/2020 and Lusófona University, ULHT. Authors are also thankful to FCT/MCTES for the financial support to CESAM (UIDP/50017/2020, UIDB/50017/2020), through national funds. The authors are grateful to the Carla Vânia (iMedUlisboa) for her collaboration in HPLC analysis and Jesús Molpeceres (Faculty of Pharmacy, University of Alcalá) for donating the 8505C cell line.

Research Areas: Pharmacology & Pharmacy ABSTRACT - Staphylococcus aureus biofilm-associated infections are a major public health concern. Current therapies are hampered by reduced penetration of antibiotics through biofilm and low accumulation levels at infected sites, requiring prolonged usage. To overcome these, repurposing antibiotics in combination with nanotechnological platforms is one of the most appealing fast-track and costeffective approaches. In the present work, we assessed the potential therapeutic benefit of three antibiotics, vancomycin, levofloxacin and rifabutin (RFB), through their incorporation in liposomes. Free RFB displayed the utmost antibacterial effect with MIC and MBIC50 below 0.006 µg/mL towards a methicillin susceptible S. aureus (MSSA). RFB was selected for further in vitro studies and the influence of different lipid compositions on bacterial biofilm interactions was evaluated. Although positively charged RFB liposomes displayed the highest interaction with MSSA biofilms, RFB incorporated in negatively charged liposomes displayed lower MBIC50 values in comparison to the antibiotic in the free form. Preliminary safety assessment on all RFB formulations towards osteoblast and fibroblast cell lines demonstrated that a reduction on cell viability was only observed for the positively charged liposomes. Overall, negatively charged RFB liposomes are a promising approach against biofilm S. aureus infections and further in vivo studies should be performed. info:eu-repo/semantics/publishedVersion

The task-specific design of ionic liquids (ILs) has emerged in several industrial and pharmaceutical applications. The family of ILs with fluorine tags equal to or longer than four carbon atoms, the fluorinated ionic liquids (FILs), combine the best properties of ILs with the ones of perfluorinated compounds, and are being designed for several specific purposes. In the pharmaceutical field, there is an urgency to search for novel antibacterial agents to overcome problems associated to antimicrobial resistances. Then, the main purpose of this work is to evaluate the environmental impact and the ability of FILs to be used as antibacterial agents against Pseudomonas stutzeri bacteria. Beyond its rare pathogenicity, these bacteria are also used as a bioremediation agent to treat several contamination sites. Then, it is important to determine which FILs have antibacterial properties, and which do not impact the bacterial growth. The biocompatibility of FILs was also evaluated through their hemolytic activity and represent a step forward the application of FILs in pharmaceutical applications. The results proved that high concentrations of FILs can have a reduced ecotoxicity and a high biocompatibility. [C8C1Im][CF3SO3] was identified as the most promising compound to be used as an antibacterial agent since it prevents the growth of bacteria at concentrations compatible with the red blood cells’ viability. publishersversion published

In drug discovery and drug development, it is estimated that around 40% of commercialized and 90% of under-study drugs have inadequate pharmaceutical properties, severely impairing its therapeutic efficacy. Thus, there is a strong demand to find strategies to enhance the delivery of such drugs. Ionic liquids are a novel class of liquids composed of a combination of organic salts that are of particular interest alone or in combination with drug delivery systems. This review is focused on the recent efforts using ionic liquids in drug solubility, formulation and drug delivery with specific emphasis on nanotechnology. The latest developments using hybrid delivery systems obtained upon the combination of drug delivery systems and ionic liquids will also be addressed., This work was supported by Fundacão para a Ciência e a Tecnologia (FCT) of Portugal provided financial support (iMed.ULisboa: UIDB/04138/2020 and UIDP/04138/2020) and by the Associate Laboratory for Green Chemistry LAQV (financed by national funds from FCT/MCTES, UIDB/50006/2020).

Bone infections caused by Staphylococcus aureus are a major concern in medical care, particularly when associated with orthopedic-implant devices. The ability of the bacteria to form biofilms and their capacity to invade and persist within osteoblasts turn the infection eradication into a huge challenge. The reduction of antibiotic penetration through bacterial biofilms associated with the presence of persistent cells, ability to survive in the host, and high tolerance to antibiotics are some of the reasons for the difficult treatment of these infections. Effective therapeutic approaches are urgently needed. In this sense, lipid-based nanosystems, such as liposomes, have been investigated as an innovative and alternative strategy for the treatment of implant-associated S. aureus infections, due to their preferential accumulation at infected sites and interaction with S. aureus. This review highlights the recent advances on antibiotic-loaded liposome formulations both in vitro and in vivo and how the interaction with S. aureus biofilms may be improved by modulating the liposomal external surface. Graphical Abstract.

Currently, insulin can only be administered through the subcutaneous route. Due to the flaws associated with this route, it is of interest to orally deliver this drug. However, insulin delivered orally has several barriers to overcome as it is degraded by the stomach&rsquo, s low pH, enzymatic content, and poor absorption in the gastrointestinal tract. Polymers with marine source like chitosan are commonly used in nanotechnology and drug delivery due to their biocompatibility and special features. This work focuses on the preparation and characterization of mucoadhesive insulin-loaded polymeric nanoparticles. Results showed a suitable mean size for oral administration (&lt, 600 nm by dynamic laser scattering), spherical shape, encapsulation efficiency (59.8%), and high recovery yield (80.6%). Circular dichroism spectroscopy demonstrated that protein retained its secondary structure after encapsulation. Moreover, the mucoadhesive potential of the nanoparticles was assessed in silico and the results, corroborated with ex-vivo experiments, showed that using chitosan strongly increases mucoadhesion. Besides, in vitro and in vivo safety assessment of the final formulation were performed, showing no toxicity. Lastly, the insulin-loaded nanoparticles were effective in reducing diabetic rats&rsquo, glycemia. Overall, the coating of insulin-loaded nanoparticles with chitosan represents a potentially safe and promising approach to protect insulin and enhance peroral delivery.

Tuberculosis is a leading cause of death worldwide. Although the development of new antimycobacterial drugs is an obvious and necessary strategy to address the disease, improving the therapeutic performance of drugs already approved constitutes a valuable alternative approach. As the lung is the most affected organ, where M. tuberculosis is able to survive and proliferate, the direct pulmonary delivery of antitubercular drugs comprises a highly promising therapeutic strategy. In this work, spray-dried locust bean gum (LBG) microparticles were used to deliver a combination of two first line antitubercular drugs, isoniazid (INH) and rifabutin (RFB), to the alveolar zone, where macrophages hosting the bacteria reside. LBG is expected to mediate favoured macrophage uptake of microparticles, leading to enhanced therapeutic effect. The therapeutic effect of LBG/INH/RFB microparticles was evaluated in a murine model infected with M. tuberculosis, strain H37Rv and compared with oral co-therapy of INH and RFB in the free form. The pulmonary administration of LBG/INH/RFB microparticles 5 times per week was the only treatment schedule that provided negative growth index values in lung (-0.22), spleen (-0.14) and liver (-0.26) even using a lower therapeutic dose for both antibiotics. For the control group, the respective values were +1.95, +0.75 and +0.96. UID/DTP/04138/2019; UID/Multi/04326/2019; FRH/BD/115628/2016 info:eu-repo/semantics/publishedVersion

Solid lipid nanoparticles (SLN) containing rifabutin (RFB), with pulmonary administration purposes, were developed through a technique that avoids the use of organic solvents or sonication. To facilitate their pulmonary delivery, the RFB-loaded SLN were included in microspheres of appropriate size using suitable excipients (mannitol and trehalose) through a spray-drying technique. Confocal analysis microscopy showed that microspheres are spherical and that SLN are efficiently microencapsulated and homogeneously distributed throughout the microsphere matrices. The aerodynamic diameters observed an optimal distribution for reaching the alveolar region. The dry powder's performance during aerosolization and the in vitro drug deposition were tested using a twin-impinger approach, which confirmed that the microspheres can reach the deep lung. Isothermal titration calorimetry revealed that SLN have higher affinity for mannitol than for trehalose. Upon microsphere dissolution in aqueous media, SLN were readily recovered, maintaining their physicochemical properties. When these dry powders reach the deep lung, microspheres are expected to readily dissolve, delivering the SLN which, in turn, will release RFB. The in vivo biodistribution of microencapsulated RFB-SLN demonstrated that the antibiotic achieved the tested organs 15 and 30 min post pulmonary administration. Their antimycobacterial activity was also evaluated in a murine model of infection with a Mycobacterium tuberculosis strain H37Rv resulting in an enhancement of activity against M. tuberculosis infection compared to nontreated animals. These results suggest that RFB-SLN microencapsulation is a promising approach for the treatment of tuberculosis.

Infectious diseases in the skin represent a major group of pathologies that contribute annually for significant health economic expenses. According to WHO, Buruli Ulcer (BU) and Cutaneous Leishmaniasis (CL) are two neglected tropical diseases for which therapy remains inadequate. Topical delivery of therapeutics constitutes an advantageous alternative to treat infected skin lesions as it allows a direct treatment of affected areas avoiding unwanted systemic effects and reducing the drug dosage. However, effective topical delivery of antimicrobial agents is still a challenge. The emergence of difficult-to-treat skin mycobacteriosis such as BU or the increasing incidence of CL highlights the need for new antimicrobial agents and new delivery systems. In the present review problems related to mycobacterial and parasitic infected skin lesions will be particularly focused as well as new alternative strategies for their treatment. Currently, progresses and challenges in constructing nanocarrier platforms for delivering various antimicrobial drugs for infected skin lesions have been attempted. This article reviews the potential of these nanocarriers in the treatment of cutaneous infections, especially regarding mycobacteria and Leishmania caused skin lesions. Nanostructured biomaterials, such as lipid-based nanocarriers, have unique physicochemical properties enabling the topical application of antimicrobial drugs, thereby overcoming some of the limitations of conventional therapies. These nanosystems have been investigated for the topical delivery of well-known drugs or new therapeutic candidates. This approach is just the beginning of a stimulating nanotechnological area.

Pancreatic cancer is one of the most lethal cancers, with an extremely poor prognosis. The development of more effective therapies is thus imperative. Natural origin compounds isolated from Plectranthus genus, such as parvifloron D (PvD), have cytotoxic and antiproliferative activity against human tumour cells. However, PvD is a very low water-soluble compound, being nanotechnology a promising alternative strategy to solve this problem. Therefore, the aim of this study was to optimize a nanosystem for preferential delivery of PvD to pancreatic tumour cells. Albumin nanoparticles (BSA NPs) were produced through a desolvation method. Glucose cross-linking and bioactive functionalization profiles of BSA platform were elucidated and analysed using static lattice atomistic simulations in vacuum. Using the optimized methodology, PvD was encapsulated (yield higher than 80%) while NPs were characterized in terms of size (100&ndash, 400 nm) and morphology. Importantly, to achieve a preferential targeting to pancreatic cancer cells, erlotinib and cetuximab were attached to the PvD-loaded nanoparticle surface, and their antiproliferative effects were evaluated in BxPC3 and Panc-1 cell lines. Erlotinib conjugated NPs presented the highest antiproliferative effect toward pancreatic tumour cells. Accordingly, cell cycle analysis of the BxPC3 cell line showed marked accumulation of tumour cells in G1-phase and cell cycle arrest promoted by NPs. As a result, erlotinib conjugated PvD-loaded BSA NPs must be considered a suitable and promising carrier to deliver PvD at the tumour site, improving the treatment of pancreatic cancer.

Persimmon (Diospyros kaki L.), a fruit rich in phenolic compounds (PCs), has been considered effective in mitigating oxidative damage induced by an excess of reactive oxygen species. Due to large molecular weight and intrinsic instability in some physiological fluids, PCs&rsquo, passage through biological membranes is very limited. Carriers like phytosomes are promising systems to optimize oral absorption of encapsulated extracts. This work prepared and fully characterized phytosomes containing bioactive phenolic extracts from persimmon in terms of size, surface charge, encapsulation efficiency and stability over six months. These phytosomes were orally dosed to Wistar rats during a 15-day period. Afterwards, haematological and biochemical analyses were performed. Monodisperse phytosomes were successfully prepared, with size less than 300nm (PI &lt, 0.3) and high encapsulation efficiency (97.4%) of PCs. In contrast to free extract, extract-loaded phytosomes had higher antioxidant activity after 6 months storage. Oral administration of extract-loaded phytosomes and free extract did not lead to lipidic profile changes and were within referenced normal ranges, as well as glycaemia levels and urine parameters. The results highlighted the potential of persimmon PCs as food supplements or pharmacological tools, suggesting a promising and safe phytosomal formulation containing bioactive agents of persimmon that could lead to health benefits.

Aim: Preclinical evaluation of a cytotoxic copper (II) complex formulated in long circulating nanoliposomes for melanoma treatment. Materials & methods: Liposomal nanoformulations of the copper complex were characterized in terms of thermodynamic behavior (differential scanning calorimeter), pH-sensitivity (spectrophotometry) and antiproliferative effects against murine melanoma B16F10 cells in vitro. Preclinical studies were performed in a C57BL/6 syngeneic melanoma model. Results: Nanoformulations were thermodynamically stable, and CHEMS-containing nanoliposomes were pH-sensitive and preserved the antiproliferative properties of the copper compound. These nanoformulations significantly impaired tumor progression in vivo, devoid of toxic side effects, compared with control mice or mice treated with the free metallodrug. Conclusion: Copper complex-containing nanoliposomes demonstrate high anticancer efficacy and safety, constituting a step forward to the development of more effective therapeutic strategies against melanoma.

Colorectal carcinoma is a complex malignancy and current therapies are hampered by systemic toxicity and tumor resistance to treatment. In the field of cancer therapy, copper (Cu) compounds hold great promise, with some reaching clinical trials. However, the anticancer potential of Cu complexes has not yet been fully disclosed due to speciation in biological systems, leading to inactivation and/or potential side effects. This is the case of the widely studied Cu(II) complexes featuring phenanthroline ligands, with potent antiproliferative effects in vitro, but often failing in vivo. Aiming to overcome these limitations and maximize its anticancer effects in vivo, the Cu(II) complex (Cu(1,10-phenanthroline)Cl2) (Cuphen), displaying IC50 values

Aim: To improve the potential of trifluralin (TFL) in the management of Leishmania infantum infections through the synthesis of analogs (TFLA) and incorporation in nanoparticulate drug delivery systems (NanoDDS), liposomes and solid lipid nanoparticles, for selective targeting to leishmania infection sites. Material & methods: In vitro screening of 18 TFLA was performed by flow cytometry. NanoDDS were loaded with active TFLA and evaluated for antileishmanial efficacy in mice through determination of parasite burden in liver and spleen. Results: The in vitro testing revealed the most active and nontoxic TFLAs, which were selected for the in vivo studies based on high incorporation in liposomes and lipid nanoparticles (>90%). Selected TFLA nanoformulations showed superior antileishmanial activity in mice (parasite burden >80%), over free TFLA and Glucantime. Conclusion: The modification of TFL structure to obtain active TFLA, together with their incorporation in NanoDDS, improved their in vivo performance against L. infantum infection.

Cancer is a major health concern and the prognosis is often poor. Significant advances in nanotechnology are now driving a revolution in cancer detection and treatment. The goal of this study was to develop a novel hybrid nanosystem for melanoma treatment, integrating therapeutic and magnetic targeting modalities. Hence, we designed long circulating and pH-sensitive liposomes loading both dichloro(1,10-phenanthroline) copper (II) (Cuphen), a cytotoxic metallodrug, and iron oxide nanoparticles (IONPs). The synthetized IONPs were characterized by transmission electron microscopy and dynamic light scattering. Lipid-based nanoformulations were prepared by the dehydration rehydration method, followed by an extrusion step for reducing and homogenizing the mean size. Liposomes were characterized in terms of incorporation parameters and mean size. High Cuphen loadings were obtained and the presence of IONPs slightly reduced Cuphen incorporation parameters. Cuphen antiproliferative properties were preserved after association to liposomes and IONPs (at 2 mg/mL) did not interfere on cellular proliferation of murine and human melanoma cell lines. Moreover, the developed nanoformulations displayed magnetic properties. The absence of hemolytic activity for formulations under study demonstrated their safety for parenteral administration. In conclusion, a lipid-based nanosystem loading the cytotoxic metallodrug, Cuphen, and displaying magnetic properties was successfully designed.

Pancreatic cancer is the eighth leading cause of cancer death worldwide. For this reason, the development of more effective therapies is a major concern for the scientific community. Accordingly, plants belonging to Plectranthus genus and their isolated compounds, such as Parvifloron D, were found to have cytotoxic and antiproliferative activities. However, Parvifloron D is a very low water-soluble compound. Thus, nanotechnology can be a promising delivery system to enhance drug solubility and targeted delivery. The extraction of Parvifloron D from P. ecklonii was optimized through an acetone ultrasound-assisted method and isolated by Flash-Dry Column Chromatography. Then, its antiproliferative effect was selectivity evaluated against different tumor cell lines (IC50 of 0.15 &plusmn, 0.05 &mu, M, 11.9 &plusmn, 0.7 &mu, M, 21.6 &plusmn, 0.5, 34.3 &plusmn, 4.1 &mu, M, 35.1 &plusmn, 2.2 &mu, M and 32.1 &plusmn, 4.3 &mu, M for BxPC3, PANC-1, Ins1-E, MCF-7, HaCat and Caco-2, respectively). To obtain an optimized stable Parvifloron D pharmaceutical dosage form, albumin nanoparticles were produced through a desolvation method (yield of encapsulation of 91.2%) and characterized in terms of size (165 nm, PI 0.11), zeta potential (&minus, 7.88 mV) and morphology. In conclusion, Parvifloron D can be efficiently obtained from P. ecklonii and it has shown selective cytotoxicity to pancreatic cell lines. Parvifloron D nanoencapsulation can be considered as a possible efficient alternative approach in the treatment of pancreatic cancer.

Aim: To investigate how surface charge and hydrophilicity affect the mucopermeation of liposomes across intestinal mucus. Methodology: Rhodamine-labeled liposomes (∼120–130 nm) with different surface charges were investigated for their capacity to flux across fresh porcine jejunal mucus in a microchannel device. Fluorescent microscopy and tracking analysis were used to measure liposome movement, while fluorescence lifetime imaging microscopy was utilized to determine mucus pH. Results: Mucopermeation was dependent on hydrophilicity and surface charge – anionic liposomes permeated more than cationic. The most cationic liposomal prototype agglomerated mucus. Presence of Na+, K+ and Mg2+ increased both speed and straightness of the pathways for all prototypes. Cationic but not anionic liposomes caused acidification (pH 2.5). Conclusion: Acidification caused by cationic liposomes explains their ability to interfere with mucus stability. Surface charge of liposomes strongly influences mucopermeation capability.

The objective of the present work was to characterize the ability of liposomes and cyclodextrin (CyD) complexes to modulate the in vivo profile of fluticasone (FTZ). In vitro cell compatibility tests were performed, exposing A549 cells to FTZ in the free form and FTZ associated to liposomes and complexed with CyD. The in vivo fate of a selected FTZ liposomal formulation and of several FTZ CyD complexes was achieved following intranasal instillation or pulmonary administration in BALB/c mice, respectively. For pulmonary administration, an inhalation chamber was constructed to enable the simultaneously pulmonary administration to six mice. Thirty minutes and 3 h after administration, mice were sacrificed, their blood, lungs, livers, and spleens were removed, and FTZ level was determined by HPLC using an extraction procedure. The in vitro tests revealed no toxic effects of FTZ formulations, as cellular viability was always superior to 90% for FTZ concentrations ranging from 5 to 60 &micro, M 72 h after incubation. The in vivo biodistribution results showed that FTZ incorporated in liposomes resulted in 20 and 30 times higher accumulation in the lungs in comparison with free FTZ, at 0.5 and 3 h after i.n. administration, respectively. FTZ associated to Hydroxypropyl-&gamma, cyclodextrin (HP-CyD) was the complex that permitted the higher accumulation of FTZ in the lungs in comparison with the respective free form. The results also suggest that the inhalation chamber apparatus can effectively facilitate the evaluation of in vivo inhalation. The establishment of an animal model of asthma allows us to further study the therapeutic efficacy of the developed FTZ formulations.

Tuberculosis (TB) is a leading cause of death amongst infectious diseases. The low permeation of antimycobacterial agents and their difficult access to infected macrophages necessitate long-term use of high drug doses. Liposomes preferentially accumulate in macrophages, increasing the efficacy of antibiotics against intracellular parasites. In the present work, several rifabutin (RFB) liposomal formulations were developed and characterised and their in vivo profile was compared with free RFB following intravenous administration. With the RFB liposomal formulations tested, higher concentrations of the antibiotic were achieved in liver, spleen and lungs 24h post administration compared with free RFB. The concentration of RFB in these organs was dependent on the rigidity of liposomal lipids. The liposomal RFB formulation prepared with dipalmitoyl phosphatidylcholine:dipalmitoyl phosphatidylglycerol (DPPC:DPPG) was the most effective and was selected for biological evaluation in a mouse model of disseminated TB. Compared with mice treated with free RFB, mice treated with the DPPC:DPPG RFB formulation exhibited lower bacterial loads in the spleen (5.53 log(10) vs. 5.18 log(10)) and liver (5.79 log(10) vs. 5.41 log(10)). In the lung, the level of pathology was lower in mice treated with encapsulated RFB. These results suggest that liposomal RFB is a promising approach for the treatment of extrapulmonary TB in human immunodeficiency virus co-infected patients., This work was supported by grants from FCT (POCTI/FCB/36416/99) and from the Health Services of FCG. Fellowships were granted by FCT (SFRH/BD/9624/2002- GABBA Program to A. Cruz and SFRH/BD/15911/2005 to A.G. Fraga)