RESUMO
Nanoemulsions are dispersions of oil-in-water (O/W) and water-in-oil (W/O) immiscible liquids. Thus, our main goal was to formulate a nanoemulsion with low surfactant concentrations and outstanding stability using Copaiba balsam oil (Copaifera sp.). The high-energy cavitation homogenization with low Tween 80 levels was employed. Then, electrophoretic and physical mobility properties were assessed, in addition to a one- and two-year physicochemical characterization studies assessment. Copaiba balsam oil and nanoemulsions obtained caryophyllene as a major constituent. The nanoemulsions stored at 4 ± 2 °C exhibited better physical stability. Two years after formulation, the nanoemulsion showed a reduction in the particle size. The size underwent changes in gastric, intestinal, and blood pH, and the PdI was not changed. In FTIR, characteristic bands of sesquiterpenes and overlapping bands were detected. When subjected to freezing and heating cycles, nanoemulsions did not show macroscopic changes in higher concentrations. Nanoemulsions subjected to centrifuge force by 1000 rpm do not show macroscopic instability and phase inversion or destabilization characteristics when diluted. Therefore, the nanoemulsion showed stability for long-term storage. The nematode Caenorhabditis elegans was used to assess the potential toxicity of nanoemulsions. The nanoemulsion did not cause toxicity in the animal model, except in the highest concentration tested, which decreased the defecation cycle interval and body length. The toxicity and stability outcomes reinforce the nanoemulsions' potential for future studies to explore pharmacological mechanisms in superior experimental designs.
RESUMO
Tuberculosis is an intracellular infectious disease caused by Mycobacterium tuberculosis, which mainly affects the lungs. Especially in patients infected by the Human Immunodeficiency Virus (HIV) or other immunosuppressed patients, tuberculosis is considered one of the infectious diseases with higher morbidity and mortality rates. Despite considerable improvements in diagnosis and treatment during the last decades, the drugs currently used in tuberculosis treatment still have limitations, such as low plasma levels after oral administration, low solubility in water, fast metabolization by the liver with a short 1/2 life and low patient adherence to treatment. Another limiting point is drug-resistant strains. Thus, to overcome such limitations, nanotechnology emerges as a promising alternative due to the drug release systems and its recent advances that show potential improvements, such as improved bioavailability and reduction of the therapeutic dose. In this context, this manuscript aimed to highlight the nanotechnology-based drug delivery systems studies pointing to those most effective for tuberculosis treatment. Studies based on polymeric nanoparticles are promising in diagnosing, treating, and even preventing tuberculosis because they have the high stability and transport capacity of these drugs. Solid lipid nanoparticles are another type of promising nanocarriers for treating tuberculosis, mainly for delivering drugs to the remote lymphatic system. Other promising nanosystems are the liposomes, since they have also shown efficacy in significantly reducing bacterial load compared to conventional drug administration. Given the results presented, the administration of drugs through nanotechnology-based drug delivery systems has benefits in treating tuberculosis since in vitro and in vivo studies have revealed that nanotechnology through nano- and micro-scale systems is an effective and promising approach for the treatment of tuberculosis. Furthermore, the increase in the number of patents for nanosystems aimed at treating TB has demonstrated researchers' commitment in the quest to improve the therapeutic arsenal against tuberculosis.