Nanoemulsions and nanocapsules loaded with Melaleuca alternifolia essential oil for sepsis treatment.

Sepsis represents a complex clinical syndrome that results from a harmful host response to infection. The infections most associated with sepsis are pneumonia, intra-abdominal infection, and urinary tract infection. Tea tree oil (TTO) has shown high antibacterial activity; however, it exhibits low aqueous solubility and high volatility, which have motivated its nanoencapsulation. In this study, the performance of nanoemulsions (NE) and nanocapsules (NC) loaded with TTO was compared. These systems were prepared by spontaneous emulsification and nanoprecipitation methods, respectively. Poly-ε-caprolactone or Eudragit® RS100 were tested as polymers for NCs whereas Tween® 80 or Pluronic® F68 as surfactants in NE preparation. Pluronic® F68 and Eudragit® RS100 resulted in more homogeneous and stable nanoparticles. In accelerated stability studies at 4 and 25 °C, both colloidal suspensions (NC and NE) were kinetically stable. NCs showed to be more stable to photodegradation and less cytotoxic than NEs. After sepsis induction by the cecal ligation and puncture (CLP) model, both NE and NC reduced neutrophil infiltration into peritoneal lavage (PL) and kidneys. Moreover, the systems increased group thiols in the kidney and lung tissue and reduced bacterial growth in PL. Taken together, both systems showed to be effective against injury induced by sepsis; however, NCs should be prioritized due to advantages in terms of cytotoxicity and physicochemical stability.

Vasorelaxant effect of standardized extract of Cecropia glaziovii Snethl encapsulated in PLGA microparticles: In vitro activity, formulation development and release studies.

In this study, the standardized dry extract of C. glaziovii (SDE) provided a significant vasorelaxant effect after contractions induced by phenylephrine in rat aortic rings in an endothelium-dependent manner, confirming that endothelial factors are needed to stimulate this response. A vasorelaxation close to that of acetylcholine was achieved, justifying the development of new formulations for this plant material. In this context, microparticles were selected to encapsulate SDE and the double emulsion technique was considered because of the hydrophilic nature of plant material. Two experimental designs were applied. Firstly, the effect of formulation parameters on particle size, size distribution and encapsulation efficiency (EE) was evaluated. As low EE was achieved, the effect of the osmotic pressure of the external phase was evaluated in a second experimental design. The presence of the osmotic agent (NaCl) impacted positively on the EE and slower in vitro release profile was obtained, which is desired in controlled release systems. The formation of denser and less porous particle surface, which was identified by SEM analysis, contributes to explain these findings. Microstructures showed to be a promising delivery system for the C. glaziovii SDE considering that a sustained release was achieved.

Development and effect of storage on the stability of enriched flavonoid fraction of Cecropia glaziovii-loaded PLGA nanoparticles.

Studies employing Cecropia glaziovii Snethl leaves have shown great potential in regard to their antiviral activity, mainly related to the phenolic compounds present in this species. The main goal of this work is to combine the therapeutic potential of this species with new technological strategies targeted at the development of an herbal nanoparticulate system for the preparation of a phytotherapeutic formulation. Poly (lactic-co-glycolic acid) nanoparticles containing the enriched flavonoid fraction of Cecropia glaziovii Snethl were developed through a study for the choice of preparation technique, amount of drug and surfactants used. These nanostructured systems were characterized by particle size, polydispersity, zeta potential, encapsulation efficiency and drug-loading capacity. A stability study of the formulations was conducted at room temperature over a period of 60 days. The optimal formulation that best fit the characteristics of the encapsulated material was determined. Sorbitan monooleate and the poloxamer 188 resulted in better colloidal stability, added to the organic and aqueous phases, respectively. These findings suggest that in the field of nanoparticles stability, it is important to evaluate the composition of the nanoparticulate system. This work highlights the importance of the optimization process, searching for a good formulation with suitable structural stabilization.