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Although rare, amoebic keratitis (AK) is a disease caused by Acanthamoeba spp. that can lead to blindness. The drugs currently available for its treatment are very toxic, which has ...motivated the investigation for more effective and safe therapeutic options. In this study, the in vitro activity of ß-caryophyllene (BCP) was exploited taking into account its action against other protozoans as well as its well-known healing and anti-inflammatory properties (aspects relevant for the AK pathogenesis). On the other hand, high volatilization and oxidation phenomena are found for this compound, which led to its incorporation into nanoemulsions (NEs). Two emulsifying agents were tested, resulting in monodisperse systems with reduced droplet size (<265 nm) and high surface charge (positive and negative for NEs prepared with cetrimonium bromide −CTAB and Phosal® 50+, respectively). NEs prepared with CTAB were shown to be more stable after long-term storage at 4 and 25 °C than those prepared with Phosal®. Pure BCP, at the highest concentration (500 µM), resulted in a level of inhibition of Acanthamoeba trophozoites equivalent to that of reference drug (chlorhexidine). This activity was even greater after oil nanoencapsulation. The reduced droplet size could improve the interaction of the oil with the microorganism, justifying this finding. Changes in surface charge did not impact the activity. Positively charged NEs improved the interaction and retention of BCP in the cornea and thus should be prioritized for further studies.
Abstract
Background
A liquid chromatography (LC) stability-indicating method was developed and validated for the quantitative determination of bilastine in coated tablets.
Objective
The procedure was ...validated for specificity, linearity, robustness, precision, and accuracy. Plackett-Burmann experimental design was used to determine the robustness of the method.
Method
Chromatographic separation was performed on a Shim-pack® RP-18 column with fluorescence detection. The degradation products formed under oxidative conditions were isolated and identified using high-resolution mass spectrometry (HRMS). In silico prediction of degradation products and in silico toxicity studies were also performed.
Results
The LC method presented good recovery and precision (intraday and interday), the response was linear in a range of 0.20 to 0.70 μg mL−1, and the results demonstrated the robustness of the analytical method under the evaluated conditions.
Conclusions
The degradation products were identified as benzimidazole (DP1) and amine N-oxide of bilastine (DP2). The results for the toxicity studies demonstrated the high mutagenic potential of DP1 and hepatotoxicity and hERG I inhibitor effects of DP2.
Highlights
Bilastine degradation products were identified as benzimidazole and amine N-oxide using HRMS.
Aim: A new stability-indicating liquid chromatography method was developed and validated for the quantitative determination of luliconazole. Materials and methods: Preliminary forced degradation ...study demonstrated an additional peak of the degradation product at the same retention time to the drug, due to this, the method was developed optimizing the chromatographic conditions to provide sufficient peak resolution (R ≥ 2). The experimental design was evaluated to assess the robustness and the best chromatographic conditions to be used for the validation. Methodology: Luliconazole solutions were exposed to various stress conditions to evaluate the method indication stability, in which the degradation product (DP-1) formed was isolated, identified, and evaluated in silico to predict degradation pathway and toxicity. The procedure was validated by robustness, selectivity, linearity, precision, and accuracy. Liquid chromatography was performed in a Phenomenex® RP-18 column with a mixture of acetonitrile and 0.3% (v/v) triethylamine solution as a mobile phase in isocratic elution. Results and conclusions: The method demonstrated robustness, good recovery, precision, linear response over a range from 5.0 to 40.0 μg.mL-1, and to be stability indicating. The alkaline stress condition resulted in the formation of DP-1. hrms studies identified this product as an hydroxyacetamide derivative, and in silico studies did not show toxic potential.
To investigate the heart rate (HR) and its autonomic modulation at baseline and during dynamic postexercise (P(EX)) with intensities of 40% and 60% of the maximum HR in healthy elderly.
This ...cross-sectional study included ten apparently healthy people who had been submitted to a protocol on a cycle ergometer for 35 minutes. Autonomic modulation was evaluated by spectral analysis of HR variability (HRV).
A relevant increase in HR response was observed at 15 minutes postexercise with intensities of 60% and 40% of the maximum HR (10±2 bpm versus 5±1 bpm, respectively; P=0.005), and a significant reduction in HRV was also noted with 40% and 60% intensities during the rest period, and significant reduction in HRV (RR variance) was also observed in 40% and 60% intensities when compared to the baseline, as well as between the post-exercise intensities (1032±32 ms versus 905±5 ms) (P<0.001). In the HRV spectral analysis, a significant increase in the low frequency component HRV and autonomic balance at 40% of the maximum HR (68±2 normalized units nu versus 55±1 nu and 2.0±0.1 versus 1.2±0.1; P<0.001) and at 60% of the maximum HR (77±1 nu versus 55±1 nu and 3.2±0.1 versus 1.2±0.1 P<0.001) in relation to baseline was observed. A significant reduction of high frequency component at 40% and 60% intensities, however, was observed when compared to baseline (31±2 nu and 23±1 nu versus 45±1 nu, respectively; P<0.001). Moreover, significant differences were observed for the low frequency and high frequency components, as well as for the sympathovagal balance between participants who reached 40% and 60% of the maximum HR.
There was an increase in the HR, sympathetic modulation, and sympathovagal balance, as well as a reduction in vagal modulation in the elderly at both intensities of the PEX.
New therapeutic agents for amoebic keratitis are needed considering that drugs currently marketed are toxic and not effective against protozoan cystic forms. The antimicrobial action of essential ...oils (EOs) is already reported in the literature, which has motivated investigations of their anti-
Acanthamoeba
potential. Unlike synthetic drugs, plant materials have been often identified as less cytotoxic. In this review, the anti-
Acanthamoeba
potential of EOs was demonstrated not only based on the anti-protozoan activity as anti-inflammatory activity. Finally, in vitro cytotoxicity studies of EOs active were analyzed. EOs were able to prevent the conversion of the protozoan trophozoite to cystic form. In a study performed with
Trachyspermum ammi
EO, 100% of
Acanthamoeba
cysts were eliminated.
Thymus capitatus
and
Limonium oleifolium
EOs showed to be more active against
Acanthamoeba
, presenting IC
50
values close to chlorhexidine and lower than amphotericin B. For these two OEs, low in vitro cytotoxicity was also found, which result in a high selectivity index (SI > 10). Therefore, safer and more effective therapies could be achieved with OEs, and in vivo assays should be urgently performed to confirm these benefits.
Graphical abstract
Luliconazole is an imidazole agent, used for the treatment of fungi infection, especially dermatophytes. The mechanism of action of the drug consisting in inhibits sterol 14α-demethylase which ...interferes with ergosterol biosynthesis. Due to low aqueous solubility and highly lipophilic, there is a need to develop drug delivery systems (nanocarriers) capable to increase the solubility, permeability, and skin retention of luliconazole, and promote a better therapeutic effect. In this context, this review presents characteristics, properties, nanocarriers, and analytical methods used for luliconazole. From the analyzed studies, the majority reports the use of RP-HPLC techniques for luliconazole determination, but also are cited spectrophotometric UV methods. The luliconazole has been qualitatively and quantitatively analyzed in different matrices, such as raw material and pharmaceutical formulations, however, in this review, only one study was found with the luliconazole quantification biological matrix, demonstrating the lack of studies related to the quantification of the drug in biological matrices. The drug quantification in different matrices by analytical methods is of great importance since they assist in the control of the quality, efficacy, and safety of the medicine.
Abstract
A new stability-indicating liquid chromatography method was developed for the quantification of empagliflozin and two synthetic impurities. The chromatographic conditions included ...Spherisorb® RP-18 column (150 × 4.6 mm, 5 μm) with a PDA detector, using acetonitrile and formic acid (pH 4.0) as mobile phase in gradient elution and flow-rate of 1.2 mL·min−1. The gradient increasing from 51 to 100% acetonitrile until 11.00 min, followed by decreasing the solvent from 100% to the initial ratio from 11.01 to 15.00 min. The method was validated according to International Council of Harmonization guidelines. The LOD and LOQ values for impurities A and B were 35 and 15 ng·mL−1, respectively, (for LOD) and 115 and 35 ng.mL−1, respectively (for LOQ). The method was linear in the range of 80–140, 115–1150 and 35–350 ng·mL−1 for EMPA, impurities A and B, respectively, and the correlation coefficient were > 0.999 in all situations, indicating the method good linearity. The developed method showed a good recovery for empagliflozin and added impurities. The method has proven to be precise, demonstrated values less than 2.0% to empagliflozin and 5.0% to synthetic impurities, robust and selective with no interference from other products in the determination of analytes. The in silico toxicity prediction suggested that the impurities do not present any toxicity risk for the parameters evaluated.
Drugs used to treat leprosy such as dapsone (DAP) can result in various adverse effects when administered orally. The disease-causing pathogen has a preferential distribution in peripheral regions of ...the body and symptoms are manifested primarily in the skin and peripheral nerves. This aspect motivated, in this study, the development of topical formulations containing DAP. Nanoemulsions (NEs) were selected as drug carriers aiming to enhance cutaneous permeation and sustain the drug release. Chaulmoogra oil (CH) was added to the oily nucleus of the NEs considering its history of use in leprosy and its potential healing effect in the skin lesions caused by Mycobacterium leprae. CH effect on formulation characteristics (size, PDI, surface load and stability) and epithelial cell migration was evaluated. CH-based NEs showed to be more monodisperse than NEs without CH (PDI ≤0.26 vs. 0.37). The droplet diameter increased from 189.7 to 227.0 nm when the CH content ranged from 2 to 4%, respectively. Hot-stage analyses and accelerated stability studies revealed that the CH improves both the physical and thermal stability of these nanocarriers. NEs with higher CH content presented greater interaction with the human skin in spectroscopic analyses, which was confirmed by permeation studies. These same formulations increased the amount of DAP retained in the skin (3.40 μg cm−2 in the epidermis and 1.60 μg cm−2 in the dermis) when compared to the nanoemulsion (NE) containing the lowest CH content (2.01 μg cm−2 in the epidermis and 1.06 μg cm−2 in the dermis). Another positive effect is that free and nanoencapsulated CH improved cell migration, which would be useful to treat skin lesions that commonly appear in patients with leprosy. Both free CH and NE provided a wound closure of 70 and 69%, respectively. In summary, the presence of CH is able to improve the anti-leprosy formulation characteristics and provide different benefits to patients.
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This study describes the development and validation of a new environmentally friendly analytical method for the determination of bilastine in coated tablets and the evaluation of its capacity to be ...stability-indicating as well. The ecofriendly analytical method was validated by specificity, linearity, accuracy, precision and robustness by reversed-phase high-performance liquid chromatography (RP-HPLC) according to International Conference on Harmonization guidelines (ICH) and Association of Official Analytical Chemists (AOAC). Isocratic LC separation was achieved on a RP18 column using a mobile phase of sodium dihydrogen phosphate aqueous buffer solution adjusted to pH (6.0 ± 0.1) with o-phosphoric acid (85% v/v) and triethylamine (0,3% v/v) and ethanol (EtOH) in the following proportions (60:40 v/v), at a flow rate of 1.0 mL·min-1 at temperature-controlled at 30 °C. The analytical method showed selectivity, good recovery and precision (intra- and inter-day), robustness, and linear over a range from 5.0 to 50 μg·mL-1.
Ferroptosis is a form of cell death that has received considerable attention not only as a means to eradicate defined tumour entities but also because it provides unforeseen insights into the ...metabolic adaptation that tumours exploit to counteract phospholipid oxidation
. Here, we identify proferroptotic activity of 7-dehydrocholesterol reductase (DHCR7) and an unexpected prosurvival function of its substrate, 7-dehydrocholesterol (7-DHC). Although previous studies suggested that high concentrations of 7-DHC are cytotoxic to developing neurons by favouring lipid peroxidation
, we now show that 7-DHC accumulation confers a robust prosurvival function in cancer cells. Because of its far superior reactivity towards peroxyl radicals, 7-DHC effectively shields (phospho)lipids from autoxidation and subsequent fragmentation. We provide validation in neuroblastoma and Burkitt's lymphoma xenografts where we demonstrate that the accumulation of 7-DHC is capable of inducing a shift towards a ferroptosis-resistant state in these tumours ultimately resulting in a more aggressive phenotype. Conclusively, our findings provide compelling evidence of a yet-unrecognized antiferroptotic activity of 7-DHC as a cell-intrinsic mechanism that could be exploited by cancer cells to escape ferroptosis.
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