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This study aims to develop a nano-sized fluoridated layered double hydroxide (LDH)-based release system via hydrothermal treatment for the controlled delivery of fluoride (F-) ions in the oral environment. The synthesis of conventional LDH-type (C-LDH) precursor nanomaterials was conducted using a co-precipitation method at constant pH, and the nanoparticulate-LDH (N-LDH) was synthesized by a hydrothermal procedure. Fluoride LDH (F-LDH) products were obtained through indirect synthesis using the precursor ion-exchange technique by varying the agitation time (2 and 24 h) and temperature (25 and 40 °C) to produce 12 material samples. The materials were characterized by energy dispersive x-ray, hexamethyldisilazane, digital radiography x-ray, Fouriertransform infrared, thermogravimetric analysis, and scanning electron microscopy. Additionally, the F-release kinetic profile was evaluated for 21 d in neutral and acid media with mathematical model analysis. Products with varying F-quantities were obtained, revealing specific release profiles. In general, there was a higher F-release in the acid medium, with emphasis on F-LDH-8. Fluoride-LDH and controlled fluoride delivery was successfully obtained, proving the potential of these nanomaterials as alternative anti-caries agents. [ABSTRACT FROM AUTHOR]

Lipases have key roles in insect lipid acquisition, storage, and mobilization and are also fundamental to many physiological processes in insects. Lipids are an important component of insect diets, where they are hydrolyzed in the midgut lumen, absorbed, and used for the synthesis of complex lipids. The South American palm weevil Rhynchophorus palmarum is one of the most important pests on commercial palm plantations. However, there are few studies about lipid digestion for this insect. In this work, we have described the biochemical characterization of the lipase activity in the posterior midgut of the R. palmarum palm weevil. Lipase activity was highest between the temperatures of 37 °C and 45 °C and at pH 6.5. Lipase activity was also sensitive to variations in salt and calcium concentrations. Lipases have been described structurally as enzymes with the Ser-His-Asp Catalytic Triad, containing an active serine. The serine protease inhibitor PMSF (phenylmethane sulfonyl fluoride) inhibited the lipases from R. palmarum, demonstrating the importance of a serine residue for this activity. The ability of the lipases to hydrolyze p-Nitrophenyl esters with different chain lengths has revealed the activities of a broad range of substrates. The lipase activities of R. palmarum increased in the presence of reduced glutathione (GSH) and dithiothreitol (DTT), while in the presence of oxidized glutathione (GSSG), activities were drastically reduced. To our knowledge, this study has provided the first information about lipase activity in the R. palmarum palm weevil. [ABSTRACT FROM AUTHOR]

Objective: In this study, oral sustained release mucoadhesive nystatin tablets were developed to increase nystatin contact time with the oral cavity and mask its unpleasant taste. Methods. The best formulation studied included sustained release agents and it was submitted to physical-mechanical characterization, taste assessment and clinical test in twelve patients. The ultraviolet-visible nystatin methodology was also developed and validated in parallel as an alternative to the pharmacopoeial microbiological dosage method. Results. The best formulation developed in this study included sustained release agents. The efficacy of this formulation was verified through a clinical assessment, showing that this formulation is more effective (100%) than the commercial oral nystatin suspension used traditionally (50%). Moreover, the UV absorption spectrophotometry method developed to validate the methodology for nystatin content analysis for new oral tablets was shown to be specific, linear, exact and reproducible, as recommended by the ICH regulations. Conclusion. The oral nystatin tablets developed showed to present faster therapeutic response than the oral aqueous solution through the preliminary clinical assays. The UV absorption spectrophotometry method showed to be an attractive test for the usual routine in the pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Herein we describe inclusion complexes of commercial sunscreens in cyclodextrins and montmorillonites to generate new sunscreen derivatives with optimized functional properties such as water resistance and skin adherence. Four cyclodextrins (α-, β-, and γ-cyclodextrin, and β-dimethyl cyclodextrin) and two montmorillonites (sodium and alkylammonium) were investigated for encapsulating some commercial sunscreens. Our results reveal a good yield and inclusion products with functional properties obtained by using kneading technique on Eusolex® 2292 and Eusolex® 6007 in β-cyclodextrin and solubilization method on Eusolex® 6007 and NeoHeliopan® MA in montmorillonite. In addition, molecular modeling studies indicated flexibility as important for the intercalation of the host molecule. [ABSTRACT FROM AUTHOR]

Purpose: Quercetin is a flavonoid known for its therapeutic properties and for forming complexes. Although the antimony-quercetin (SbQ) complex has been produced before, no previous exploration of its characteristics has been published in literature. Thus, this study aimed to characterize this complex, assess its stability and investigate its complexation site through its antibacterial activity. Methods: The SbQ complex was synthetized using Sb(III) potassium tartrate trihydrate and quercetin anhydrous (1:1) (v/v) as a solution and dried using three methods: rotaevaporation, lyophilization and spray drying. The material, in solution, was analyzed by UV-vis and fluorimetry; and, in the powder, by X-ray diffraction (XRD), both scanning electronic and fluorescence microscopy and infrared spectroscopy (FT-IR). Antimicrobial activity was evaluated via broth microdilution. Results: UV-vis exhibited a shoulder peak at 291 nm indicating metal chelation at C-ring of quercetin and confirmed 1:1 stoichiometry. Spectrofluorimetry showed an increase of intensity with the complex formation with an emission band (525 nm). After drying, XRD and SEM indicated loss of crystallinity and a difference in shape and size of the complex compared to its precursors. FT-IR suggested by a shift of frequency of the carbonyl group (1661 cm-1) that the quercetin bond to antimony by the C-3, followed by positions C-5 and C-4 carbonyl, which has been confirmed by MIC through the structure-activity relationship of the antibacterial activity of quercetin. Conclusion: These results provided a characterization of SbQ complex with the confirmation of its binding site, working as a guide for future studies involving this complex., (© 2019 The Author (s).)

Layered double hydroxides have received more attention from researchers due to their range of applications, ease of synthesis and low cost of production. With broader knowledge about solar radiation effects on the body, the use of sunscreens has become even more important. The ability of some nanostructures, such as layered double hydroxides, to act as matrices has made it possible to obtain improvements in photoprotective formulations, with solutions to problems caused by radiation and sunscreens. This review article brings together the most recent advances of these clays, the layered double hydroxides, applied to photoprotection.

Objective: To evaluate the healing action of green and red propolis, correlating it with the content of flavonoids., Methods: We performed quantification of total flavonoids of green and red propolis ethanol extracts for subsequent incorporation in ointment base to 20%. We used 20 Wistar rats divided into four groups: 0.9% saline (S), ointment base (B), green propolis ointment (G) and red propolis ointment (R). All animals were submitted to excisional lesions in the midian back region. The rats were treated daily for 15 days. During this period we observed weight, body temperature and diameters of the wounds. For histological analysis, samples were collected from wounds. At the end of the experiment we performed blood collection and removal of the kidney and liver for biochemical and histological analyzes., Results: The levels of total flavonoids of green (4.50%) and red (5.92%) propolis were high (> 2%), but, while the latter showed a content larger than the former, the evolution of green propolis was better in the repair of wounds, both macroscopically and histologically. There were no nephrotoxicity or hepatotoxicity, a result confirmed by biochemical tests (ALT and albumin). Propolis influenced the reduction of total cholesterol, triglycerides and glucose., Conclusion: There was no correlation between total flavonoid contents and the healing action of propolis. This reveals the need for elucidation of the flavonoids found in each class of propolis to unravel which one(s) would be important for the healing process.

Purpose: This work describes the preparation of new nanocomposites based on lamellar silicates (AAM-alkyl ammonium montmorillonite) obtained by the intercalation of PVP K30 and glyceril monostearate., Methods: By XRD, TGA and DSC analysis the AAM was characterized and its compactation characteristics, functionality and toxicity were also tested. The AAM/PVP K-30 and AAM/GME nanocomposite obtained were evaluated to identify the interlamellar spacing values by XRD diffratograms. Tablets were prepared using methyldopa and theophylline as model drugs and the dissolution tests were carried out in simulated gastric fluid and simulated enteric fluid., Results: AAM showed a good compactability and compressibility characteristics for tablets preparation. The intercalation yields (approximately 25%) of the nanocomposites were efficient. The AAM/PVP K-30 nanocomposites were successfully tested as dissolution enhancers and sustained release matrixes., Conclusions: The results also suggested the promising use of AAM (viscogel B8) and the new nanocomposite prepared by clay/PVP K-30 intercalation as a new matrix for sustained release and the feasibility of using these new nanocomposites as dissolution enhancer.

Objective: In this study, oral sustained release mucoadhesive nystatin tablets were developed to increase nystatin contact time with the oral cavity and mask its unpleasant taste., Methods: The best formulation studied included sustained release agents and it was submitted to physical-mechanical characterization, taste assessment and clinical test in twelve patients. The ultraviolet-visible nystatin methodology was also developed and validated in parallel as an alternative to the pharmacopoeial microbiological dosage method., Results: The best formulation developed in this study included sustained release agents. The efficacy of this formulation was verified through a clinical assessment, showing that this formulation is more effective (100%) than the commercial oral nystatin suspension used traditionally (50%). Moreover, the UV absorption spectrophotometry method developed to validate the methodology for nystatin content analysis for new oral tablets was shown to be specific, linear, exact and reproducible, as recommended by the ICH regulations., Conclusion: The oral nystatin tablets developed showed to present faster therapeutic response than the oral aqueous solution through the preliminary clinical assays. The UV absorption spectrophotometry method showed to be an attractive test for the usual routine in the pharmaceutical industry.

The pentavalent antimonies, mainly the meglumine antimoniate, are recommends as first-choice medicines for leishmaniasis therapy. In this work we described the development of formulations of meglumine antimoniate injectable medication, as well as the analytical methodology used in the selective determination of Sb(III) and Sb(Total) by hydride generation - inductively coupled plasma atomic emission spectrometry (HG-ICP-AES) and ICP-AES, respectively. On that purpose the analytical methodology was developed focusing on the HG-ICP-AES technique. The formulations using propylene glycol/water as vehicles in a 20:80 proportion were more appropriate for subsequent use in industrial scale. These formulations also showed a lower variation on Sb(III) percentage, no need of buffer solution to stabilize the formulation and no influence of the autoclaving in the quality of the product. The results of the development of the analytical methodology point out the proposed method as an efficient alternative for the determination of Sb(III) in the presence of large quantities of Sb(V) in injectable solutions of meglumine antimoniate, in a selective, linear, accurate and precise manner. In addition, the method showed a low limit of quantification, less interference of the matrix, and more resilience than batch techniques proposed in the Brazilian Pharmacopeia.