Health Sciences Research Centre

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Publications

Interactions of phenolic compounds with ovalbumin: a spectroscopic approach

Publication . Vapor, Alcides; Tomaz, Cândida T.; Mendonça, António

Ovalbumin (OVA) is the major protein in egg white and can cause allergy mainly in infants and young children. Egg allergy is an IgE mediated reaction and is one the most common food allergies. So far, the avoidance of the egg has been the unique way to prevent this allergy. It is well known that phenolic compounds can bind to proteins promoting structural and functional changes and, phenolic compounds are been recognized as having a potent antioxidant, anti-inflammatory and antitumoral activity. In this work, the interactions between OVA and the phenolic compounds were studied through spectroscopic techniques (fluorescence, circular dichroism (CD), Fourier transform infrared spectroscopy (FTIR)) and docking. spectroscopy (FTIR)) and docking.

2019-11-14Conference object

Open access

Ibuprofen loaded PVA/chitosan membranes: A highly efficient strategy towards an improved skin wound healing

Publication . Morgado, Patrícia I.; Miguel, Sónia P.; Correia, Ilídio Joaquim Sobreira; Ricardo, Ana Aguiar

During wound healing, an early inflammation can cause an increase of the wound size and the healing process can be considerably belated if a disproportionate inflammatory response occurs. (S)-ibuprofen (IBP), a non-steroidal anti-inflammatory agent, has been used for muscle healing and to treat venous leg ulcers, but its effect in skin wound healing has not been thoroughly studied thus far. Herein, IBP-β-cyclodextrins carriers were designed to customise the release profile of IBP from poly(vinyl alcohol)/chitosan (PVA/CS) dressings in order to promote a faster skin regeneration. The dressings were produced using supercritical carbon dioxide (scCO2)-assisted technique. In vitro IBP release studies showed that β-cyclodextrins allowed a controlled drug release from the hydrogels which is crucial for their application in wound management. Moreover, the in vivo assays revealed that the presence of PVA/CS membranes containing IBP-β-cyclodextrins carriers avoided scab formation and an excessive inflammation, enabling an earlier skin healing.

2016-12-13Journal article

Restricted access

Establishment of 2D Cell Cultures Derived From 3D MCF‐7 Spheroids Displaying a Doxorubicin Resistant Profile

Publication . Nunes, Ana Raquel Santos; Costa, Elisabete C.; Barros, Andreia; Diogo, Duarte Miguel de Melo; Correia, Ilídio Joaquim Sobreira

In vitro 3D cancer spheroids generally exhibit a drug resistance profile similar to that found in solid tumors. Due to this property, these models are an appealing for anticancer compounds screening. Nevertheless, the techniques and methods aimed for drug discovery are mostly standardized for cells cultured in 2D. The development of 2D cell culture models displaying a drug resistant profile is required to mimic the in vivo tumors, while the equipment, techniques, and methodologies established for conventional 2D cell cultures can continue to be employed in compound screening. In this work, the response of 3D‐derived MCF‐7 cells subsequently cultured in 2D in medium supplemented with glutathione (GSH) (antioxidant agent found in high levels in breast cancer tissues and a promoter of cancer cells resistance) to Doxorubicin (DOX) is evaluated. These cells demonstrated a resistance toward DOX closer to that displayed by 3D spheroids, which is higher than that exhibited by standard 2D cell cultures. In fact, the 50% inhibitory concentration (IC50) of DOX in 3D‐derived MCF‐7 cell cultures supplemented with GSH is about eight‐times higher than that obtained for conventional 2D cell cultures (cultured without GSH), and is only about two‐times lower than that attained for 3D MCF‐7 spheroids (cultured without GSH). Further investigation revealed that this improved resistance of 3D‐derived MCF‐7 cells may result from their increased P‐glycoprotein (P‐gp) activity and reduced production of intracellular reactive oxygen species (ROS).

2018-09Journal article

Restricted access

Development of poly-2-ethyl-2-oxazoline coated gold-core silica shell nanorods for cancer chemo-photothermal therapy

Publication . Moreira, André; Rodrigues, Ana Carolina Félix; Reis, Ana Catarina Almeida; Costa, Elisabete C.; Ferreira, Paula; Correia, Ilídio Joaquim Sobreira

Aim: Develop a new poly-2-ethyl-2-oxazoline (PEOZ)-based coating for doxorubicin-loaded gold-core mesoporous silica shell (AuMSS) nanorods application in cancer chemo-photothermal therapy. Methods: PEOZ functionalized AuMSS nanorods were obtained through the chemical grafting on AuMSS of a PEOZ silane derivative. Results: The PEOZ chemical grafting on the surface of AuMSS nanorods allowed the neutralization of nanodevices’ surface charge, from -30 to -15 mV, which improved nanoparticles’ biocompatibility, namely by decreasing the blood hemolysis to negligible levels. In vitro antitumoral studies revealed that the combined treatment mediated by the PEOZ-coated AuMSS nanorods result in a synergistic effect, allowing the complete eradication of cervical cancer cells. Conclusion: The application of the PEOZ coating improves the AuMSS nanorods performance as a multifunctional combinatorial therapy for cervical cancer.

2018-10Journal article

Restricted access

Preclinical performance of vaginal semisolid products: technological and safety evaluations assuming physiologic parameters

Publication . Machado, Rita Solange Monteiro; Oliveira, José António Martinez Souto de; Oliveira, Rita Manuela Palmeira de

Vaginal semisolid products preclinical evaluations, when performed considering the particularities of the target organ, may represent key tools to predict in vivo performance. Before heading to clinical phases, vaginal semisolids must demonstrate to have an adequate technological and safety profile, in order to achieve higher success rates in the human testing stage. Traditional characterization methods currently used for vaginal semisolids do not undertake an integrative approach, since they do not address, for example, vaginal pH, fluid and temperature. Moreover, early safety assessment methods are largely described and validated not only on scientific literature, but also by regulatory agencies, although they are still mainly focused on cellular-based models. This safety profile of products can be further improved by combining toxicity testing, with drug release and permeation studies. Indeed, the vaginal administration route allows for local and systemic delivery of drugs, depending on the therapeutic purpose. Consequently, the drug should be confined to the chosen location of administration, to obtain maximum efficacy while avoiding side effects. The aim of this work was to develop a full set of assessment methods for characterization of vaginal semisolid products. Commercialized formulations were used to establish new methodological approaches that could be applied in new products development and characterization. Therefore, antimicrobials, Gino-canesten®, Sertopic®, Dermofix®, Gyno-pevaryl®, Lomexin®, Gino Travogen®, Dalacin V®; oestrogens, Ovestin®, Blissel® and Colpotrophine®; and, two reference formulations, Universal Placebo and Replens® were extensively evaluated. Technologically, they were tested in terms of pH, pH-buffering capacity, osmolality, textural parameters and viscosity, using a physiologic standpoint that considered the body temperature and dilution in a physiologic volume of vaginal fluid simulant (VFS); and even an ex vivo porcine model to infer bioadhesion and rheology on an after-administration environment. In terms of safety investigation, cellular toxicity was disclosed on VK2 E6/E7, HeLa and HEC-1A cell-lines, using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and NRU (Neutral Red Uptake) assays. Tissue explants, collected from the ex vivo porcine vaginal model, were also tested concerning toxicity, through MTT and histological analysis. Moreover, to include an advanced in vitro toxicity evaluation, the HET-CAM (Hen's Egg Test – Chorioallantoic Membrane), already in validation for eye irritation testing, was applied to vaginal irritation. A HPLC-DAD (High Performance Liquid Chromatography with Diode Array Detector) quantification method for the molecules present in semisolids included in this work, was developed and validated according to FDA (Food and Drug Administration - USA), EMA (European Medicines Agency) and ICH (International Conference for Harmonization) requirements. Further, this method was applied in drug quantification on in vitro drug release and ex vivo drug permeation experiments. These two techniques were performed using dynamic vertical Franz diffusion cells, having all experimental setting being specifically designed and optimized concerning the molecules in study (estriol, clotrimazole, econazole, isoconazole, sertaconazole and fenticonazole). Concerning technological characteristics, antimicrobial formulations exhibited lower pH than topical oestrogens. Buffering capacity in a vaginal fluid simulant conducted to better predictions of what happens in vivo. Characterization was performed also for those less acidic products to assess their ability to gain physiologic pH after mixing with simulated vaginal fluids. Products osmolality after dilution in VFS were below the upper limit advised by the World Health Organization (WHO). The antimicrobials had similar textural behaviours, while topical oestrogens varied in textural parameters. A slight decrease in viscosity was observed after application of dilution and temperature factors, showing the influence of the surrogate vaginal environment, while maintaining their pseudoplastic behaviour. However, each formulation had its own profile, possibly driven by their composition. Formulations’ viscosity was higher when tested using the ex vivo administration model than when only diluted in VFS at 37ºC. Concerning the in vitro models, VK2 E6/E7, presented relatively higher viabilities than HeLa and HEC-1A cells over the tested product concentrations. Tissue viability results were much higher than those obtained for the in vitro cellular models, revealing that this model could be more robust and closer to the in vivo situation. Across models, antimicrobials showed concentration-dependent viabilities. While oestrogens presented odd profiles, depending on the formulation and concentration tested. Reference products led to the most stable and higher viability profiles across concentrations. On ex vivo permeation studies we have investigated if there were differences in performing ex vivo permeation studies using the porcine vaginal model, when collecting a proximal or a distal tissue within the vaginal tube. No extensive significant differences between these tissues were found, but the caudal vagina could be more suitable for vaginal permeation experiments since it conducted to more reproducible and consistent results. Furthermore, it was observed that drug permeation is not directly dependent on drug release from the formulation. To sum up, the conduction of this integrative preclinical assessment for vaginal semisolids can be a valuable approach in new products development or characterisation, since it could optimize cost-efficiency of new formulations development by predicting in vivo efficacy and safety profiles. In addition, these methodologies have great potential not only to be applied in cosmetics, medical devices and medicines industry, but also in academical research.

2018-01Doctoral thesis

Open access