Effects of imidazolium ionic liquids on skin barrier lipids - Perspectives for drug delivery

Ionic liquids (ILs) have great potential to facilitate transdermal and topical drug delivery. Here, we investigated the mechanism of action of amphiphilic ILs 1-methyl-3-octylimidazolium bromide (C8MIM) and 3-dodecyl-1-methylimidazolium bromide (C12MIM) in skin barrier lipid models in comparison to their complex effects in human skin. C8MIM incorporated in a skin lipid model was a better permeation enhancer than C12MIM for water and model drugs, theophylline and diclofenac. Solid state 2H NMR and X-ray diffraction indicated that both ILs prefer the cholesterol-rich regions in skin lipids without significantly perturbing their lamellar arrangement and that C8MIM induces the formation of an isotropic lipid phase to a greater extent compared to C12MIM. C12MIM applied topically to the lipid model or human skin as a pretreatment was more potent than C8MIM. When co-applied with the drugs to human skin, aqueous C12MIM was more potent than C8MIM in enhancing theophylline permeation, but neither IL affected (even decreased) diclofenac permeation. Thus, the IL's ability to permeabilize skin lipid barrier is strongly modulated by its ability to reach the site of action and its interactions with drug and solvent. Such an interplay is far from trivial and requires detailed investigation to realize the full potential of ILs.

Synthesis, Characterization and Biocompatibility Evaluation of Novel Chitosan Lipid Micro-Systems for Modified Release of Diclofenac Sodium

The purpose of our study was the obtaining, characterization and biocompatibility estimation of novel carrier systems for diclofenac. Diclofenac is a potent nonsteroidal anti-inflammatory drug with frequent gastrointestinal side effects, impairing the quality of the patient's life. Original diclofenac-loaded micro-vesicles coated with chitosan were prepared and physico-chemical analyzed. We investigated their in vitro hemocompatibility and in vivo biocompatibility in rats. The animals were treated orally as follows: group 1 (Control): distilled water 0.3 mL/100 g body weight; Group 2 (CHIT): 0.3 mL/100 g body weight 0.5% chitosan solution; Group 3 (DCF): 15 mg/kg body weight diclofenac; Group 4 (DCF-ves): lipid vesicles loaded with diclofenac 15 mg/kg body weight. Blood samples were collected for assessing: red blood cells, hemoglobin, hematocrit and leukocyte formula. A series of specific parameters of the liver and kidney function, some markers of immune defense, as well as the activity of some enzymes involved in oxidative processes, were also investigated. At the end of the experiment, the animals were sacrificed and fragments of liver, kidney and stomach were collected for histopathological examination. No blood hemolysis was evidenced by the in vitro test with the administration of diclofenac vesicles. The animals treated with diclofenac lipid vesicles stabilized with chitosan did not display any notable differences in their hematological and biochemical profile compared to control animals. These data correlated with the histological results, which showed the absence of architectural changes in the examined tissues. Biological in vitro and in vivo evaluation revealed that the microvesicles containing diclofenac are biocompatible, with potential to be used as delivery systems to modify the drug release, thus making them an attractive candidate for biomedical applications.

Passive Diffusion of Ciprofloxacin and its Metalloantibiotic: A Computational and Experimental study

Fluoroquinolones (FQ) are antibiotics widely used in clinical practise, but the development of bacterial resistance to these drugs is currently a critical public health problem. In this context, ternary copper complexes of FQ (CuFQPhen) have been studied as a potential alternative. In this study, we compared the passive diffusion across the lipid bilayer of one of the most used FQ, ciprofloxacin (Cpx), and its ternary copper complex, CuCpxPhen, that has shown previous promising results regarding antibacterial activity and membrane partition. A combination of spectroscopic studies and molecular dynamics simulations were used and two different model membranes tested: one composed of anionic phospholipids, and the other composed of zwitterionic phospholipids. The obtained results showed a significantly higher membrane permeabilization activity, larger partition, and a more favourable free energy landscape for the permeation of CuCpxPhen across the membrane, when compared to Cpx. Furthermore, the computational results indicated a more favourable translocation of CuCpxPhen across the anionic membrane, when compared to the zwitterionic one, suggesting a higher specificity towards the former. These findings are important to decipher the influx mechanism of CuFQPhen in bacterial cells, which is crucial for the ultimate use of CuFQPhen complexes as an alternative to FQ to tackle multidrug-resistant bacteria.

Unraveling the Role of Drug-Lipid Interactions in NSAIDs-Induced Cardiotoxicity

Cardiovascular (CV) toxicity is nowadays recognized as a class effect of non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs). However, their mechanisms of cardiotoxicity are not yet well understood, since different compounds with similar action mechanisms exhibit distinct cardiotoxicity. For instance, diclofenac (DIC) is among the most cardiotoxic compounds, while naproxen (NAP) is associated with low CV risk. In this sense, this study aimed to unravel the role of drug-lipid interactions in NSAIDs-induced cardiotoxicity. For that, DIC and NAP interactions with lipid bilayers as model systems of cell and mitochondrial membranes were characterized by derivative spectrophotometry, fluorometric leakage assays, and synchrotron X-ray scattering. Both DIC and NAP were found to have the ability to permeabilize the membrane models, as well as to alter the bilayers’ structure. The NSAIDs-induced modifications were dependent on the lipid composition of the membrane model, the three-dimensional structure of the drug, as well as the drug:lipid molar ratio tested. Altogether, this work supports the hypothesis that NSAIDs-lipid interactions, in particular at the mitochondrial level, may be another key step among the mechanisms underlying NSAIDs-induced cardiotoxicity.

H2S Donors Reverse Age-Related Gastric Malfunction Impaired Due to Fructose-Induced Injury via CBS, CSE, and TST Expression

Objective

Excess of fructose consumption is related to life-treating conditions that affected more than a third of the global population. Therefore, to identify a newer therapeutic strategy for the impact prevention of high fructose injury in age-related malfunctions of the gastric mucosa (GM) in the animal model is important.

Methods

Adult and aged male rats were divided into control groups (standard diet, SD) and high fructose diet (HFD) groups; acute water immersion restraint stress (WIRS) was induced for evaluation of GM adaptive response and effects of testing the therapeutic potential of H₂S-releasing compounds (H₂S donors). Histological examination of gastric damage was done on hematoxylin-eosin stained slides. Cystathionine beta-synthase (CBS), Cystathionine gamma-lyase (CSE), and Thiosulfate-dithiol sulfurtransferase (TST) activities and oxidative index were assessed during exogenous administration of H₂S donors: sodium hydrosulfide (NaHS) and the novel hybrid H₂S-releasing aspirin (ATB-340). The results showed that HFD increased gastric damage in adult and aged rats. HFD-associated malfunction characterized by low activities of H₂S key enzymes, inducing increased oxidation. Pretreatment with NaHS, ATB-340 of aged rats in the models of HFD, and WIRS attenuated gastric damage in contrast to vehicle-treated group (p < 0.05). The effect of ATB-340 was characterized by reverse oxidative index and increased CBS, CSE, and TST activities. In conclusion, H₂S donors prevent GM age-related malfunctions by enhancement of CBS, CSE, and TST expression against fructose excess injury though reduction of oxidative damage.