Browsing by Author "de Barros, Dragana P.C."
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- Dermal Delivery of Lipid Nanoparticles: Effects on Skin and Assessment of Absorption and SafetyPublication . Pinto, Fátima; Fonseca, Luis P.; de Barros, Dragana P.C.During the recent decades, dermal delivery has achieved visible popularity mainly due to the increase of chronic skin diseases and the demand for targeted delivery and patient compliance. Dermal delivery provides an attractive alternative to oral drug delivery, promoting the drug application directly at the site of action, resulting in higher localized drug concentration with reduced systemic drug exposure. Among several types of drug delivery systems used in dermal delivery are the lipid nanoparticles, which include solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). These lipid nanocarriers have attracted great interest and have been intensively studied for their use in dermal applications. Lipid nanoparticles increase the transport of active compounds through the skin by improving drug solubilization in the formulation, drug partitioning into the skin, and fluidizing skin lipids. Moreover, these nanocarriers are composed of biologically active and biodegradable lipids that show less toxicity and offer many favorable attributes such as adhesiveness, occlusion, skin hydration, lubrication, smoothness, skin penetration enhancement, modified release, improvement of formulation appearance providing a whitening effect, and offering protection of actives against degradation. This chapter focuses on the effects of lipid nanoparticles in dermal delivery, on the types of active compounds that are used in their formulation and application, some aspects related to their possible toxicity, and a description of the most commonly used techniques for the evaluation of drug absorption on the skin.
- LipNanoCar Technology – A Versatile and Scalable Technology for the Production of Lipid NanoparticlesPublication . Esgueira, Vera L.R.; Lopes, Clara P.A.; dos Santos, Ana Catarina A.; Pinto, Fátima; Sousa, Silvia A.; de Barros, Dragana P.C.; Leitão, Jorge H.; Fonseca, Luis P.The extensive knowledge in the miniemulsion technique used in biocatalysis applications by the authors allowed the development of drug delivery systems that constitutes the LipNanoCar technology core for the production of lipid nanoemulsions and solid lipid nanoparticles. The LipNanoCar technology, together with adequate formulations of different oils, fatty acids, surfactants, and temperature, allows the entrapment of several bioactive and therapeutic compounds in lipid nanoparticles for cosmetic, nutrition, and pharmaceutical applications. The LIpNanoCar technology allowed lipid nanoparticles production with average sizes ranging from 100 to 300 nm and Zeta potentials between −55 and −20 mV. Concomitantly, high entrapment or encapsulation efficiencies (%EE) were achieved, as illustrated in this work for β-carotene and vitamins derivatives (>85%) for cosmetic application, and for antibiotics currently used in chemotherapy, like rifampicin (69–85%) and pyrazinamide (14–29%) against Mycobacterium tuberculosis (TB), and ciprofloxacin (>65%) and tobramycin (~100%) in Cystic Fibrosis (CF) respiratory infections therapy. Ciprofloxacin presented, for example, a quick-release from the lipid nanoparticles using a dialysis tubing (96% in the first 7 h), but slower than the free antibiotic (95% in the first 3 h). This result suggests that ciprofloxacin is loaded near the external surface of the lipid nanoparticles. The toxicity and validation of entrapment of antibiotics in lipid nanoparticles for Cystic Fibrosis therapy were assessed using Caenorhabditis elegans as an animal model of bacterial infection. Fluorescence microscopy of an entrapped fluorescent dye (DiOC) confirmed the uptake of the lipid nanoparticles by ingestion, and their efficacy was successfully tested in C. elegans. Burkholderia contaminans IST408 and Burkholderia enocepacia K56–2 infections were tested as model bacterial pathogens difficult to eradicate in Cystic Fibrosis respiratory diseases.