Preservation of the Antioxidant Capacity of Resveratrol via Encapsulation in Niosomes.

Resveratrol (RSV) is a natural polyphenol which produces several benefits to human health, being the trans-isomer the most bioactive. However, its systemic absorption is limited due to its low water solubility, that reduces the oral bioavailability, and its chemical instability (owing to the trans-cis RSV isomer conversion upon light irradiation). Thus, encapsulation of this bioactive compound is required to protect it from destructive environmental conditions. Here, trans-RSV was encapsulated in food grade nanovesicles formed by Tween 80 and Span 80, with or without the addition of dodecanol (Dod) as membrane stabilizer. The size and shape of niosomes were evaluated by microscopy (TEM) and light scattering. RSV was successfully encapsulated in the vesicular systems (49-57%). The effect of Dod in the membrane bilayer was evaluated on the RSV in vitro release experiments under simulated gastrointestinal conditions. The total antioxidant capacity of the encapsulated polyphenol was measured using radicals' assays (DPPH and ABTS). The niosomes were able to maintain almost the total antioxidant capacity of encapsulated RSV, also preserved the ~85% of trans-RSV, thus offering considerable protection against high energy irradiation. These results make these systems suitable for different applications, particularly for photosensitive compounds.

Assessment of the in vitro activity of azithromycin niosomes alone and in combination with levofloxacin on extensively drug-resistant Klebsiella pneumoniae clinical isolates.

BACKGROUND AND AIM: Extensively drug-resistant (XDR) Klebsiella pneumoniae represent a major threat in intensive care units. The aim of the current study was to formulate a niosomal form of azithromycin (AZM) and to evaluate its in vitro effect on XDR K. pneumoniae as a single agent or in combination with levofloxacin. MATERIAL AND METHODS: Forty XDR K. pneumoniae isolates (23 colistin-sensitive and 17 colistin-resistant) were included in the study. Formulation and characterization of AZM niosomes were performed. The in vitro effect of AZM solution/niosomes alone and in combination (with levofloxacin) was investigated using the checkerboard assay, confirmed with time-kill assay and post-antibiotic effect (PAE). RESULTS: The AZM niosome mean minimal inhibitory concentration (MIC) (187.4 ± 209.1 µg/mL) was significantly lower than that of the AZM solution (342.5 ± 343.4 µg/mL). AZM niosomes/levofloxacin revealed a 40% synergistic effect compared to 20% with AZM solution/levofloxacin. No antagonistic effect was detected. The mean MIC values of both AZM niosomes and AZM solution were lower in the colistin-resistant group than in the colistin-sensitive group. The mean PAE time of AZM niosomes (2.3 ± 1.09 h) was statistically significantly longer than that of the AZM solution (1.37 ± 0.5 h) (p = 0.023). CONCLUSION: AZM niosomes were proved to be more effective than AZM solution against XDR K. pneumoniae, even colistin-resistant isolates.

Supramolecular Nanostructures for Vaccines.

Although this is an era of pandemics and many devastating diseases, this is also a time when bionanotechnology flourishes, illuminating a multidisciplinary field where vaccines are quickly becoming a balsam and a prevention against insidious plagues. In this work, we tried to gain and also give a deeper understanding on nanovaccines and their way of acting to prevent or cure cancer, infectious diseases, and diseases caused by parasites. Major nanoadjuvants and nanovaccines are temptatively exemplified trying to contextualize our own work and its relative importance to the field. The main properties for novel adjuvants seem to be the nanosize, the cationic character, and the biocompatibility, even if it is achieved in a low dose-dependent manner.

Metabolic Activity of Anthocyanin Extracts Loaded into Non-ionic Niosomes in Diet-Induced Obese Mice.

PURPOSE: Anthocyanins (ACNs) are polyphenols that might reduce pathological processes associated with type 2 diabetes mellitus and other chronic diseases, but their bioavailability is still controversial. In this study, the metabolic activity of oral delivery of ACN-loaded niosomes was investigated and evaluated in a diet-induced obesity (DIO) mice model. METHODS: ACNs extracted from Vaccinium Meridionale by the supercritical fluid extraction method were loaded in niosomes. The niosomal formulation was physically characterized and further administrated in drinking water to obese, insulin resistant mouse. We evaluated the effect of ACN loaded niosomes on hyperglycemia, glucose and insulin intolerance and insulin blood levels in C57BL/6 J mice fed with a high-fat diet. RESULTS: The ACN-loaded particles were moderately monodisperse, showed a negative surface charge and 57% encapsulation efficiency. The ACN-loaded niosomes ameliorated the insulin resistance and glucose intolerance in the DIO mice model. Additionally, they reduced animal weight and plasma insulin, glucose, leptin and total cholesterol levels in obese mice. CONCLUSION: ACN-loaded niosomes administration, as a functional drink, had a beneficial effect on the reversal of metabolic abnormalities associated with obesity.

Niosomes and liposomes as promising carriers for dermal delivery of Annona squamosa extract

The leaf extract of Annona squamosa L. has antibacterial, antidiabetic, antioxidant, and anticancerous activities. The present work aims to compare between liposomes and niosomes as carriers for A. squamosa extract to improve its transdermal bioavailability. Physical characterization for niosomes and liposomes was performed using: transmission electron microscope (TEM), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). In addition, the encapsulation efficiency for A. squamosa in both carriers was evaluated and in-vitro drug release experiments were performed. The results proved the potential of both carriers to penetrate the outer layer of the skin (stratum corneum) which is considered as a strong barrier against the diffusion of many compounds through the skin. Moreover, the results pointed out that niosomes and liposomes lasted long time through the skin, which ensures the presence of antioxidant extract in the skin for prolonged periods. This would have a benefit of targeting free radicals in the skin. The encapsulation efficiency of liposomes for A. squamosa extract exceeded that of niosomes, however, niosomes demonstrated longer time of drug release through the skin. In conclusion, niosomes and liposomes are promising carriers for dermal delivery of the antioxidant extract Annona squamosa.

Formulation design and characterization of a non-ionic surfactant based vesicular system for the sustained delivery of a new chondroprotective agent

Diacerein is used for symptomatic relief and cartilage regeneration in osteoarthritis. Due to gastrointestinal side effects, poor aqueous solubility and low bioavailability, its clinical usage has been restricted. The objective of the present study was to enhance its dissolution profile and to attain sustained release by designing a novel delivery system based on niosomes. Five niosomal formulations (F1-F5) with non-ionic surfactant (sorbitan monostearate) and cholesterol in varying ratios of 5:5, 6:4, 7:3, 8:2 and 9:1 were developed by the reverse-phase evaporation technique. The size and polydispersivity index (PDI) were found in the range of 0.608 µm to 1.010 µm and 0.409 to 0.781, respectively. Scanning electron microscopy (SEM) of the selected formulation (F3) revealed spherical vesicles, and 79.8% entrapment was achieved with F3 (7:3). Dissolution studies using the dialysis method showed sustained release behaviour for all formulations. The optimized surfactant-to-cholesterol concentration (7:3) in formulation F3sustained the drug-release time (T50%) up to 10 hours. Kinetic modelling exhibited a zero-order release (R2=0.9834) and the release exponent 'n' of the Korsmayer-Peppas model (n=0.90) confirmed non-fickian and anomalous release. The results of this study suggest that diacerein can be successfully entrapped into niosomes using sorbitan monostearate and that these niosomes have the potential to deliver diacerein efficiently at the absorption site.

A diacereína é usada para o alívio sintomático e para a regeneração da cartilagem na osteoartrite. Devido aos efeitos adversos gastrointestinais, baixa solubilidade aquosa e biodisponibilidade, o seu uso clínico tem sido restrito. O objetivo do presente estudo foi melhorar o perfil de dissolução deste fármaco e obter liberação prolongada através do planejamento de um novo sistema de liberação designado de niossoma. Cinco formulações distintas de niossomas (F1 a F5) contendo tensoativos não iônicos (monoestearato de sorbitano) e colesterol, em diferentes proporções, de 5:5, 6:4, 7:3, 8:2 e 9:1, foram desenvolvidas através da técnica de evaporacão de fase reversa. Os tamanhos e índices de polidispersibilidade (PDI) obtidos variam entre 0,608 e 1,01 µm e entre 0,409 e 0,7781, respectivamente. Imagens de microscopia electrônica de varrimento (SEM) da formulação selecionada (F3) revelaram vesículas esféricas. Obteve-se encapsulação de 79,8% com a formulação F3 (7:3). Estudos de dissolução usando o método de diálise demonstraram padrão de liberacão prolongada para todas as formulações. A proporção de tensoativo e colesterol (7:3) na formulacão F3 prolongou o tempo de liberação do fármaco (T50%) até 10 horas. Estudos de modelação cinética demonstraram ordem de liberacão zero (R2=0,9834) e o expoente de liberação "n" do modelo de Korsmayer-Peppas (n=0.90) confirmou a liberação não-fickiana e anômala. Os resultados deste estudo sugerem que a diacereína pode ser encapsulada com sucesso no interior de niossomas, utilizando monostearato de sorbitano, o qual tem potencial para liberar, eficientemente, a diacereína no local de absorção.

Efficacy of free glutathione and niosomal glutathione in the treatment of acetaminophen-induced hepatotoxicity in cats.

Acetaminophen (APAP) administration results in hepatotoxicity and hematotoxicity in cats. The response to three different treatments against APAP poisoning was evaluated. Free glutathione (GSH) (200mg/kg), niosomal GSH (14 mg/kg) and free amino acids (180 mg/kg of N-acetylcysteine and 280 mg/kg of methionine) were administered to cats that were intoxicated with APAP (a single dose of 150 mg/kg, p.o.). Serum concentration of alanine aminotransferase (ALT) along with serum, liver and erythrocyte concentration of GSH and methemoglobin percentage were measured before and 4, 24 and 72 hours after APAP administration. Free GSH (200 mg/kg) and niosomal GSH (14 mg/kg) were effective in reducing hepatotoxicity and hematotoxicity in cats intoxicated with a dose of 150 mg/kg APAP. We conclude that both types of treatments can protect the liver and haemoglobin against oxidative stress in APAP intoxicated cats. Furthermore, our results showed that treatment with niosomal GSH represents an effective therapeutic approach for APAP poisoning.