Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC): Occlusive Effect and Penetration Enhancement Ability

Objective: This work compares the occlusive effect and the penetration enhancement ability of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), through in vitro skin. Methods: SLN and NLC were prepared by high shear homogenization and characterized by size, polydispersity index, zeta potential, morphology and physical stability. Occlusive effect was assessed by an in vitro test and by measuring TEWL using pig skin. Skin treated with the lipid carriers was visualized by SEM. A penetration test through skin, followed by tape stripping, was carried out using Nile red as a marker. Results: SLN (200 ± 6 nm) and NLC (192 ± 11 nm) were obtained. An occlusion factor of 36% - 39% was observed for both systems, while a reduction in TEWL of 34.3% ± 14.8% and 26.2% ± 6.5% was seen after treatment with SLN and NLC, respectively. SEM images showed a film formed by the lipid carriers, responsible for the occlusion observed. No differences were found between the occlusive effect produced by SLN and NLC in both tests. NLC allowed the penetration of a greater amount of Nile red than SLN: 4.7 ± 1.3 μg and 1.7 ± 0.4 μg, respectively. Conclusion: Both carriers form a film on the skin, providing an occlusive effect with no differences between these two systems. The penetration of a marker (Nile red) into the stratum corneum was quite higher for NLC than for SLN, suggesting an influence of the composition of these particles on their penetration enhancing ability.

Comparative Analysis of the Antioxidant and Free-Radical Scavenging Activities of Different Water-Soluble Extracts of Green, Black and Oolong Tea Samples

Extracts of 40 green, black or oolong high quality tea samples from China, Japan or India among others, have been prepared according to the manufacturer instructions and assayed for total polyphenols content using the Folin-Ciocalteu phenol reagent. In addition, the antioxidant activity was assessed by the CUPRAC method and the free-radical scavenging activity was determined using the antioxidant-promoting decay of the stable free-radical DPPH. Caffeine and the most important catechins were identified using RP-HPLC previously validated method. Results from this study suggest that teas, even though they content similar amounts of caffeine, differ considerably in polyphenolic content and therefore in antioxidant and free-radical scavenging activities, depending on the part of the plant used and the process applied to the material for the preparation of the final tea presentation. Correlations among Folin-Ciocalteau’s reactivity of tea samples, the neocuproine reactivity, the DPPH decolourization and the HPLC analysis suggest that the antioxidant activity is due essentially to polyphenolic compounds present in teas, mainly EGCG. The best extraction method of tea powder was the one indicated by dealers. In general, the richest samples belong to green teas and the poorest samples belong to the black teas.

Non-related contact lens coinfection with Acanthamoeba and Fusarium

Rationale: Microbial keratitis caused by coinfection with more than one species of pathogens is a severe condition with an unfavorable prognosis. Patient concerns: An immunocompetent Nepali woman complained of pain in the left eye, redness, watering and decreased vision for 5 months. Interventions: The patient was discarded and accurately diagnosed with coinfection with Fusarium sp. and Acanthamoeba sp. The habit of washing the eyes with tap water from a domestic storage tank was the most likely source of infection since it was found to be contaminated with cysts of Acanthamoeba sp. The woman received eye drops of fluconazole and natamycin(5%), cefazoline(50 mg/m L), atropine, and tablets of itraconazole(100 mg), which were later switched to eye drops of clotrimazole(1%), natamycin(5%) and voriconazole(1%), and tablets of itraconazole. A full thickness penetrating keratoplasty was performed followed by treatment with eye drops of voriconazole(1%), natamet(5%), ofloxacin, atropine and carboxymethylcellulose for one week.Outcomes: After treatment, the condition of the patient significantly improved and was discharged one week after keratoplasty. Lessons: This is the first report of Acanthamoeba keratitis in Nepal and the first report of coinfection with Fusarium in this country and highlights the importance of early diagnosis of microbial keratitis both in single microorganism infections and coinfections, even in no contact lens wearers.

Plasma Accumulations of Vitamin B6 from an Oral Dose in a New Reversible Model for Mouse Gut Injury and Regeneration

Chemically based rodent models are used to assess the positive effects promoted by foods and gut microbiota on gut health. Lectins with enzymatic activity, such as type 2 ribosome-inactivating proteins, might also prove useful for exploring these issues. Sub-lethal doses of the lectin nigrin from Sambucus nigra L. to mice promoted reversible derangement of gut epithelium by induction of apoptosis of transit amplifying cells of the small intestine crypts in a time-dependent course. The present work seeks to study vitamin B6 accumulation in plasma from an oral bolus in a mouse nigrin model. 24 h after sub-lethal nigrin b treatment, there was clear body weight reduction associated to a notable increase in Evan’s blue stain accumulation in excised small intestine, an increase in myeloperoxidase activity, and a near 50% reduction in plasma accumulation of vitamin B6. Histological analysis of small intestine sections of nigrin b-treated animals also revealed significant derangement of intestinal crypts. Seventy two hours after nigrin b treatment, stain uptake decreased and vitamin B6 accumulation was almost restored despite villi derangement. Large intestine crypts were scarcely or not at all affected. Eight days after nigrin b treatment, vitamin B6 uptake and intestinal crypt structure had fully recovered. The nigrin b mice model supports the view that, under these conditions, the carrier-mediated vitamin B6 uptake component of the small intestine crypts is probably the most active when the vitamin is administered orally as a bolus. The findings provide insights into the suitability of the present mice model for nutritional or drug absorption studies in conditions of partially altered or injured intestinal mucosa.

Concentrated Extract of Green Tea Polyphenols Enhances the Toxicity of the Elderberry Lectin Nigrin b to Mice

The effect of the administration of large amounts of green tea polyphenols is a matter of controversy. We explored whether a polyphenol mixture from a concentrated green tea extract (Polyphenon 60) could alter the effects on mice of the type 2 (two chains) ribosome-inactivating protein nigrin b isolated from Sambucus nigra L. Nigrin b triggers specific reversible toxic effects on the mouse intestines featured by apoptosis of mice Lieberkühn crypt cells upon parenteral administration of sub-lethal amounts. Independent administration to mice of 30 mg/kg body weight of Polyphenon 60 by oral gavage or 10 mg/kg body weight of nigrin b administered via the intraperitoneal route (i.p.) did not affect survival. In contrast, the simultaneous treatment greatly enhanced nigrin b toxicity leading to the death of some animals. The histological analysis revealed that the most serious injury was inflicted on the small intestine crypts, which disappeared, and on the liver, which evidenced hepatotoxicity showing haemorrhagic areas. These findings raise concerns about the abuse of high concentrations of green tea polyphenols especially when the intestinal mucosa is damaged, for instance by toxins or therapeutic drugs.

Development of Amine Capillary Column Applied to the Analysis of Basic Compounds by Electrochromatography

An amine capillary column was developed in a fused-silica capillary as stationary phase and applied to separation of basic compounds by capillary electrochromatography (CEC). The functionalized capillary was prepared by inmobilization of 3-Aminopropyl)triethoxysilane (APTES). The CEC conditions including APTES and buffer concentration, pH and applied voltage were investigated to obtain the optimal CEC system for the separation of three anesthetics as basic test molecules. The capillary column provided an efficiency of up to 20,000 plates/m. Lidocaine, ketamine and xilacine were baseline separated under the running conditions with 10 mM Na2HPO4 pH 9.0 as BGE. The applied voltage was 5 kV temperature was set at 25oC and UV detection was performed. The resolutions were 4.97 and 1.53 for ketamine, lidocaine and xilacine, respectively. The column used in CEC mode showed better separation of the anesthetics compared with those used in the capillary zone mode. The comparison with reversed stationary phases used in HPLC in terms of resolution (Rs), sensitivity (LOD), efficiency (N), precision (RSD), asymmetry (T) was also performed. This study provided an alternative way for the CEC separation of basic compounds and demonstrated the improvement in the chromatographic parameters.

The reversed intra- and extracellular pH in tumors as a unified strategy to chemotherapeutic delivery using targeted nanocarriers

Solid tumors are complex entities,comprising a wide variety of malignancies with very different molecular alterations.Despite this,they share a set of characteristics known as"hallmarks of cancer"that can be used as common therapeutic targets.Thus,every tumor needs to change its metabolism in order to obtain the energy levels required for its high proliferative rates,and these adaptations lead to alterations in extra-and intracellular pH.These changes in p H are common to all solid tumors,and can be used either as therapeutic targets,blocking the cell proton transporters and reversing the pH changes,or as means to specifically deliver anticancer drugs.In this review we will describe how proton transport inhibitors in association with nanocarriers have been designed to block the pH changes that are needed for cancer cells to survive after their metabolic adaptations.We will also describe studies aiming to decrease intracellular pH in cancer using nanoparticles as molecular cages for protons which will be released upon UV or IR light exposure.Finally,we will comment on several studies that have used the extracellular pH in cancer for an enhanced cell internalization and tumor penetration of nanocarriers and a controlled drug delivery,describing how nanocarriers are being used to increase drug stability and specificity.