Browsing by Author "Castro, Pedro M."
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- Biological potential and bioaccessibility of encapsulated curcumin into cetyltrimethylammonium bromide modified cellulose nanocrystalsPublication . Casanova, Francisca; Pereira, Carla F.; Ribeiro, Alessandra B.; Castro, Pedro M.; Freixo, Ricardo; Martins, Eva; Tavares-Valente, Diana; Fernandes, João C.; Pintado, Manuela E.; Ramos, Óscar L.Curcumin is a natural phenolic compound with important biological functions. Despite its demonstrated efficacy in vitro, curcumin biological activities in vivo are dependent on its bioaccessibility and bioavailability, which have been highlighted as a crucial challenge. Cetyltrimethylammonium bromide-modified cellulose nanocrystals (CNC-CTAB) have been shown to be effective in curcumin encapsulation, as they have the potential to enhance biological outcomes. This study evaluated the biological effects of curcumin encapsulated within CNC-CTAB structures, namely its antioxidant, anti-inflammatory and antimicrobial properties, as well as the release profile under digestion conditions and intestinal permeability. Encapsulated curcumin demonstrated antioxidant and anti-inflammatory properties, effectively reducing reactive oxygen species and cytokine production by intestinal cells. The delivery system exhibited antimicrobial properties against Campylobacter jejuni bacteria, further suggesting its potential in mitigating intestinal inflammation. The system showed the ability to protect curcumin from degradation and facilitate its interaction with the intestinal epithelium, highlighting the potential of CNC-CTAB as carrier to enhance curcumin intestinal biological functions.
- Combination of PLGA nanoparticles with mucoadhesive guar-gum films for buccal delivery of antihypertensive peptidePublication . Castro, Pedro M.; Baptista, Patrícia; Madureira, Ana Raquel; Sarmento, Bruno; Pintado, Manuela E.Oral administration of proteins and peptides still is a challenging task to overcome due to low permeability through absorptive epithelia, degradation and metabolism that lead to poor bioavailability. Attempting to overcome such limitations, an antihypertensive peptide derived from whey protein, with KGYGGVSLPEW sequence, was incorporated for the first time into polymeric nanoparticles. An experimental design was followed in order to optimize drug-loading, association efficiency, mean particle size, zeta-potential and polydispersity index of a formulation of poly(lactic-co-glycolic acid) (PLGA) nanoparticles as carriers for bioactive peptides. In sequence, peptide-loaded PLGA nanoparticles were incorporated in a guar-gum film matrix, resulting in a combined delivery system aiming to promote slow release and permeation across buccal epithelium. Neither PLGA nanoparticles, guar-gum films nor the conjugation of PLGA nanoparticles and guar-gum films (GfNp) significantly compromised in vitro TR146 human buccal carcinoma cell line viability after 12 h contact, as assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide reduction assay (MTT). In vitro release assay for developed formulations allowed to conclude that the combination of orodispersible film and nanoparticles granted a slower release of AhP when compared with PLGA or guar-gum films alone or with control. GfNp offered more effective, synergistic, in vitro permeation of TR146 cell multilayer in comparison with guar-gum films or PLGA nanoparticles alone. The combination of PLGA nanoparticles with guar-gum films represent a suitable alternative to conventional per os delivery systems, leading to an increased buccal permeability of carried antihypertensive peptide.
- Design of innovative biocompatible cellulose nanostructures for the delivery and sustained release of curcuminPublication . Casanova, Francisca; Pereira, Carla F.; Ribeiro, Alessandra B.; Costa, Eduardo M.; Freixo, Ricardo; Castro, Pedro M.; Fernandes, João C.; Pintado, Manuela; Ramos, Óscar L.Poor aqueous solubility, stability and bioavailability of interesting bioactive compounds is a challenge in the development of bioactive formulations. Cellulose nanostructures are promising and sustainable carriers with unique features that may be used in enabling delivery strategies. In this work, cellulose nanocrystals (CNC) and cellulose nanofibers were investigated as carriers for the delivery of curcumin, a model liposoluble compound. Nanocellulose modification with the surfactant cetyltrimethylammonium bromide (CTAB), tannic acid and decylamine (TADA), and by TEMPO-mediated oxidation were also tested and compared. The carrier materials were characterized in terms of structural properties and surface charge, while the delivery systems were evaluated for their encapsulation and release properties. The release profile was assessed in conditions that mimic the gastric and intestinal fluids, and cytotoxicity studies were performed in intestinal cells to confirm safe application. Modification with CTAB and TADA resulted in high curcumin encapsulation efficiencies of 90 and 99%, respectively. While no curcumin was released from TADA-modified nanocellulose in simulated gastrointestinal conditions, CNC-CTAB allowed for a curcumin-sustained release of ca. 50% over 8 h. Furthermore, the CNC-CTAB delivery system showed no cytotoxic effects on Caco-2 intestinal cells up to 0.125 g/L, meaning that up to this concentration the system is safe to use. Overall, the use of the delivery systems allowed for the reduction in the cytotoxicity associated with higher curcumin concentrations, highlighting the potential of nanocellulose encapsulation systems.
- Edible films as oral delivery systems for xanthines extracted from medicinal plants: an experimental design approachPublication . Castro, Pedro M.; Oliveira, Ana; Fonte, Pedro; Madureira, Ana Raquel; Sarmento, Bruno; Pintado, ManuelaTwo formulations of edible films intended for oral delivery of therapeutic xanthines were developed, following an experimental design approach. Gelatin type A and sodium carboxymethylcellulose were used as polymeric matrices with different physico-chemical nature. Caffeine, a well-known methylxhanthine, was used as model bioactive molecule, representing overall xanthines (e.g. caffeine, theophylline, theobromine) extracted from medicinal plants. Fourier-transform infrared spectroscopy (FTIR) analysis was performed to outwit the formation of covalent bonds between caffeine and the matrix of edible films. Scanning electron microscopy (SEM) was performed to assess if caffeine was homogeneously dispersed on the matrix of edible films. Simulation of gastrointestinal tract and ex vivo permeability studies across intestinal mucosa were performed to predict the delivery profile of caffeine from developed formulations of edible films. Gelatin type A-based edible films offered a slow release of caffeine whereas sodium carboxymethylcellulose-based edible films promote an immediate release of caffeine.
- Film-nanoparticle composite for enhanced oral delivery of alpha-casozepinePublication . Castro, Pedro M.; Baptista, Patricia; Zuccheri, Giampaolo; Madureira, Ana Raquel; Sarmento, Bruno; Pintado, Manuela E.Whey-derived alpha-casozepine bioactive peptide (YLGYLEQLLR) was associated with previously optimized guar-gum film-PLGA nanoparticles, aiming to increase both stability across gastrointestinal tract and permeability across absorptive epithelia. Oral films associated with nanoparticles (FNp) enhance buccal absorption along with protection of carried bioactive molecules that are swallowed, with inherent increase of bioavailability. None of developed formulations induced significant loss of cell viability. Permeability across both buccal and intestinal cell barriers was enhanced when alpha-casozepine was carried by FNp system, when compared with film and nanoparticles alone, in a simulated gastrointestinal tract environment. Moreover, differences in permeability profile across buccal and intestinal epithelia were in accordance with the slower erosion of PLGA nanoparticles in a media of neutral pH, resembling oral cavity conditions, and a faster erosion in acidic conditions, as occurs in stomach, as observed by a continuous analysis of nanoparticle morphology over 980 min by atomic force microscopy. Additionally, apparent permeability of alpha-casozepine across TR146 human buccal carcinoma cells and Caco-2/HT29-MTX co-culture, carried by FNp was indeed superior when compared with peptide loaded in PLGA nanoparticles and in films alone or with free peptide control solution. Both FNp and PLGA nanoparticles alone enhanced the permeability of relaxing peptide compared with guar-gum films alone. An increased tongue adhesion when PLGA nanoparticles were added to the guar-gum films was also observed. Developed formulations improved both buccal an intestinal absorption of carried bioactive molecules without compromising cell viability.
- Hydrogels containing porphyrin-loaded nanoparticles for topical photodynamic applicationsPublication . González-Delgado, José A.; Castro, Pedro M.; Machado, Alexandra; Araújo, Francisca; Rodrigues, Francisca; Korsak, Bárbara; Ferreira, Marta; Tomé, João P.C.; Sarmento, Bruno5,10,15,20-tetrakis(1-methylpyridinium-4-yl)-porphyrin tetra-iodide (TMPyP), a potent water-soluble photosensitizer (PS) used in antimicrobial applications, was encapsulated into poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TMPyP-PLGA) for topical delivery purposes. Nanoparticles resulted in a mean particle size around 130nm, narrow polydispersity index (PdI), spherical morphology and association efficiency up to 93%. Free TMPyP and TMPyP-PLGA nanoparticles were incorporated into Carbopol(®) hydrogels, resulting in controlled TMPyP release of about 60% and 20% after 4.5h, respectively. Critical properties such as appearance, clarity, viscosity and pH were maintained over time, as hydrogels were stable during 6 months at 4°C, 25°C/60% RH and 40°C/75% RH. For photodynamic applications, the photoproduction of singlet oxygen from these hydrogels was quite efficient being both formulations very photostable after 20min. No TMPyP permeation through pig ear skin was observed after 24h, and histological assays did not show relevant damages in surrounding tissues. All these excellent characteristics make them promising platforms for photodynamic applications through topical clinical use.
- Incorporation of beads into oral films for buccal and oral delivery of bioactive moleculesPublication . Castro, Pedro M.; Sousa, Flávia; Magalhães, Rui; Ruiz-Henestrosaf, Victor Manuel Pizones; Pilosoff, Ana M.R.; Madureira, Ana Raquel; Sarmento, Bruno; Pintado, Manuela EThe association of alginate beads and guar-gum films in a single delivery system was idealized to promote a more effective buccal and oral delivery of bioactive molecules. A response surface method (experimental design approach) was performed to obtain optimal formulations of alginate beads to be incorporated into guar gum oral films as combined buccal and oral delivery systems for caffeine delivery. The combined formulation was further characterized regarding physicochemical properties, drug release, cell viability and buccal permeability. Beads average size, determined by dynamic light scattering (DLS), was of 3.37 ± 6.36 μm. Film thickness was set to 62 μm. Scanning electron microscopy micrographs revealed that beads were evenly distributed onto the film matrix and beads size was in accordance to data obtained from DLS analysis. Evaluation of Fourier-transform infrared spectra did not indicate the formation of new covalent bonds between the matrix of guar-gum films, alginate beads and caffeine. In vitro release assays by dialysis membrane allowed understanding that the combination of guar-gum films and alginate beads assure a slower release of caffeine when compared with the delivery profile of free caffeine from alginate beads or guar-gum films alone. MTT assay, performed on human buccal carcinoma TR146 cell line, allowed concluding that neither guar-gum film, alginate beads nor guar-gum film incorporated into alginate beads significantly compromised cell viability after 12 h of exposure. As demonstrated by in vitro permeability assay using TR146 human buccal carcinoma cell lines, combination of guargum films and alginate beads also promoted a slower release and, thus, lower apparent permeability (1.15E–05 ± 3.50E-06) than for caffeine solution (2.68E–05 ± 7.30E-06), guar-gum film (3.12E–05 ± 4.70E-06) or alginate beads (2.01E–05 ± 3.90E-06). The conjugation of alginate beads within an orodispersible film matrix represents an effective oral/buccal delivery system that induces a controlled release along with an enhanced intimate contact with cell layers that may promote higher in vivo bioavailability of carried drugs.
- Incorporation of PLGA nanoparticles into guar-gum films as a new buccal deliveryPublication . Castro, Pedro M.; Batista, Patrícia; Madureira, Ana Raquel; Sarmento, Bruno; Pintado, Manuela E.
- Modified cellulose nanocrystals encapsulating cannabigerol: a step forward in controlling intestinal inflammatory disordersPublication . Casanova, Francisca; Pereira, Carla F.; Ribeiro, Alessandra B.; Castro, Pedro M.; Martins, Eva; Freixo, Ricardo; Tavares-Valente, Diana; Pimentel, Lígia L.; Fontes, Ana L.; Rodríguez-Alcalá, Luís M.; Fernandes, João C.; Pintado, Manuela E.; Ramos, Óscar L.Cannabigerol (CBG) from Cannabis sativa L. is known for its anti-inflammatory, antibacterial, and antioxidant properties, showing potential against intestinal inflammation. However, its lipophilic nature limits its absorption and stability. Researchers have explored cellulose nanocrystals (CNCs) to deliver lipophilic compounds and enhance their biological outcomes. This study investigated the capability of modified CNC with cetyltrimethylammonium bromide (CTAB) to effectively deliver CBG. The encapsulation process’s impact on cytotoxicity, biological activity, and controlled release during digestion was assessed. Results indicated that CNC-CTAB encapsulation significantly reduced CBG’s cytotoxicity on intestinal cells, allowing safer administration of higher doses. The antioxidant and anti-inflammatory properties of the encapsulated CBG were retained, resulting in a decrease in reactive oxygen species and cytokine levels in intestinal cells. Additionally, the system inhibited the growth of the intestinal pathogen Campylobacter jejuni. The study supports using CNC-CTAB as an efficient delivery system to enhance CBG’s potential against intestinal inflammation. Incorporating this system into food matrices could lead to novel functional foods for managing intestinal inflammation.
- Novel and revisited approaches in nanoparticle systems for buccal drug deliveryPublication . Macedo, Ana S.; Castro, Pedro M.; Roque, Luís; Thomé, Natália G.; Reis, Catarina P.; Pintado, Maria Manuela; Fonte, PedroThe buccal route is considered patient friendly due to its non-invasive nature and ease of administration. Such delivery route has been used as an alternative for the delivery of drugs that undergo first-pass metabolism or are susceptible to pH and enzymatic degradation, such as occurs in the gastrointestinal tract. However, the drug concentration absorbed in the buccal mucosa is often low to obtain an acceptable therapeutic effect, mainly due to the saliva turnover, tongue and masticatory movements, phonation, enzymatic degradation and lack of epithelium permeation. Therefore, the encapsulation of drugs into nanoparticles is an important strategy to avoid such problems and improve their buccal delivery. Different materials from lipids to natural or synthetic polymers and others have been used to protect and deliver drugs in a sustained, controlled or targeted manner, and enhance their uptake through the buccal mucosa improving their bioavailability and therapeutic outcome. Overall, the main aim of this review is to perform an overview about the nanotechnological approaches developed so far to improve the buccal delivery of drugs. Herein, several types of nanoparticles and delivery strategies are addressed, and a special focus on pipeline products is also given.