The development of formulations that maintain the biological and physical chemistry properties of essential oils is an important choice when they are used as an active ingredient. This study aimed to characterize the essential oil from leaves of Cymbopogon densiflorus and evaluate the antioxidant activity of the oil, and to produce a nanoemulsion formulation containing it. The essential oil was obtained by hydrodistillation, and seasonality was analysed every 2 months by gas chromatography–mass spectrometry, showing that more than 90% of the composition was maintained for the whole period and that the major compounds were trans‐p‐menta‐2,8‐dien‐1‐ol, cis‐p‐menta‐2,8‐dien‐1‐ol, trans‐p‐menta‐1(7),8‐dien‐2‐ol, cis‐piperitol, and cis‐p‐menta‐1(7),8‐dien‐2‐ol. Stable nanoemulsions were prepared by phase inversion method encapsulating the essential oil. The antioxidant activity was evaluated by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical scavenging and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid (ABTS) methods. In the first test, free and nanoemulsified essential oil showed half‐maximal inhibitory concentration (IC50) values equivalent to 14.689 and 3.692 mg mL−1, respectively. In the second test, these values were 0.567 and 0.43 mg mL−1. The development of nanoemulsion‐based essential oil from leaves of C. densiflorus was viable, and the formulated oil was able to reproduce the antioxidant activity at a concentration four times lower than that of the pure essential oil.

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The triterpenes α- and β-amyrins display important pharmacological activities. As a result of their high hydrophobia, they present low water solubility and reflect poor oral bioavailability. Different techniques can be used for the improvement of amyrins solubility, one of them is the use of nanoemulsions. Therefore, the method of direct emulsification was used to develop a nanoemulsion of these triterpenes and the resulting drug delivery system was characterized by an in vitro release assay. Encapsulation efficiency higher than 99% was achieved with total release around 30% in 24 h, which suggests that this system could be useful for the administration of α- and β-amyrins by different routes in an efficient way.

Tuberculosis is an infectious disease affecting mostly lungs, that is still considered a health global problem as it causes millions of deaths worldwide. Current treatment is effective but associated with severe adverse effects due to the high doses of each anti-tuberculosis drug daily administrated by oral therapy. For the first time, a pyrazinoic acid (PA) biodegradable nanoconjugate was synthesized and developed for pulmonary administration in an attempt to reduce the administered doses by achieving a high drug payload and controlled release at the target site. The conjugate was synthesized by coupling pyrazinoic acid on carboxylic groups of poly(malic acid), which is a biodegradable and biocompatible polymer, and posteriorly self-assembled into nanoconjugates. Characterization confirmed the formation of nanometric, spherical and negatively charged pyrazinoic acid nanoconjugate (NC-PA). NC-PA was stable for 60 days at 4 and 37°C and able to deliver PA in a sustained release manner over time. On macrophages, they exhibited no cell toxicity for a wide range of concentrations (from 1 to 100 µg/mL), demonstrating the safety of NC-PA. In addition, the nanoconjugate was efficiently taken up by RAW 264.7 cells over 6 hours reaching a maximum value after 3 hours of incubation. In conclusion, innovative nanoconjugates are a promising alternative to deliver drugs directly to the lungs and contributing to improving tuberculosis therapy.

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Leishmaniasis is an infectious disease responsible for a huge rate of morbidity and mortality in humans. Chemotherapy consists of the use of pentavalent antimonial, amphotericin B, pentamidine, miltefosine, and paromomycin. However, these drugs are associated with some drawbacks such as high toxicity, administration by parenteral route, and most seriously the resistance of some strains of the parasite to them. Several strategies have been used to increase the therapeutic index and reduce the toxic effects of these drugs. Among them, the use of nanosystems that have great potential as a site-specific drug delivery system stands out. This review aims to compile results from studies that were carried out using first-and second-line antileishmanial drugcarrying nanosystems. The articles referred to here were published between 2011 and 2021. This study shows the promise of effective applicability of drug-carrying nanosystems in the field of antileishmanial therapeutics, with the perspective of providing better patient adherence to treatment, increased therapeutic efficacy, reduced toxicity of conventional drugs, as well as the potential to efficiently improve the treatment of leishmaniasis.