Enamel Deproteinization: Will It Save The Shear Bond Strength For The Sake Of Preventing White Spot Lesions? / Desproteinização do esmalte: salvará a resistência ao cisalhamento para prevenir lesões de manchas brancas?

Objective: This study attempted to investigate the effect of enamel deproteinization using citric acid, PEG 400 and NaOCL on the shear bond strength of orthodontic brackets to enamel using nano-silver modified resin for the prevention of white spot lesions. Material and Methods: 68 premolars were used in the study; nano-silver modified adhesive resin was used to bond orthodontic brackets to the enamel. Specimens were divided into 4 groups according to the applied surface treatment before bonding. Group I (control): acid etching with 37% phosphoric acid. Group II: deproteinization using 5.25% sodium hypochlorite (NaOCl) before acid etching. Group III:deproteinization using 10% citric acid before acid etching. Group IV:deproteinization using 5% polyethylene glycol (PEG 400) before acid etching. The specimens were then thermo- cycled for 6000 cycles. They were examined for surface roughness, shear bond strength and using electron microscope. Results: In both surface roughness and shear bond strength tests, Group III (citric acid) showed the highest values, followed by Group II (sodium hypochlorite); (p < 0.001). The least values were shown for Groups I (control) and IV (PEG 400), with no statistically significant difference between them (p = 0.948). SEM revealed etching pattern type 1 and 2 in the citric acid group while PEG 400 showed shallower micro- porosities. Conclusions: Deproteinization of enamel using either NaOCl or citric acid increased the bond strength of nano-sliver modified resin to enamel, with citric acid showing greater increase in bond strength. Deproteinization using PEG 400 did not increase the bond strength. (AU)

Objetivo: Este estudo buscou investigar o efeito da desproteinização do esmalte utilizando ácido cítrico, PEG 400 e NaOCl na resistência ao cisalhamento de braquetes ortodônticos ao esmalte usando resina modificada com nanoprata para a prevenção de lesões de manchas brancas. Material e Métodos: 68 pré-molares foram usados no estudo; resina adesiva modificada com nanoprata foi usada para colar os braquetes ortodônticos ao esmalte. Os corpos-de-prova foram divididos em 4 grupos de acordo com o tratamento de superfície aplicado antes da colagem. Grupo I (controle): condicionamento ácido com ácido fosfórico a 37%. Grupo II: desproteinização com hipoclorito de sódio a 5,25% (NaOCl) antes do condicionamento ácido. Grupo III: desproteinização com ácido cítrico a 10% antes do condicionamento ácido. Grupo IV: desproteinização com polietilenoglicol 5% (PEG 400) antes do condicionamento ácido. As amostras foram então termocicladas por 6.000 ciclos. Eles foram examinados quanto à rugosidade da superfície, resistência ao cisalhamento e usando microscópio eletrônico. Resultados: Nos testes de rugosidade superficial e resistência ao cisalhamento, o Grupo III (ácido cítrico) apresentou os maiores valores, seguido do Grupo II (hipoclorito de sódio); (p <0,001). Os menores valores foram apresentados para os Grupos I (controle) e IV (PEG 400), sem diferença estatisticamente significativa entre eles (p = 0,948). A microscopia eletrônica revelou padrão de ataque tipo 1 e 2 no grupo de ácido cítrico, enquanto PEG 400 mostrou microporosidades mais rasas. Conclusões: A desproteinização do esmalte com NaOCl ou ácido cítrico aumentou a força de união da resina modificada com nanoprata ao esmalte, com o ácido cítrico apresentando maior aumento na força de união. A desproteinização usando PEG 400 não aumentou a resistência de união. (AU)

Investigation of Effect of Polyethylene Glycol 400 on Pharmacokinetics and Anti-inflammatory Effect of Baicalin Based on UPLC-MS/MS and Molecular Docking Techniques / 中国实验方剂学杂志

Objective:To investigate the effects of polyethylene glycol 400 （PEG400） on the pharmacokinetics and anti-inflammatory effect of baicalin， and to preliminarily explore the anti-inflammatory effects of baicalin and its main metabolite baicalein 6-<italic>O</italic>-<italic>β</italic>-<italic>D</italic>-glucuronide （B6G） by molecular docking. Method:Rats were randomly divided into two groups with water and PEG400 as the dissolving matrix， and rats were administrated the equal dose of baicalin aqueous solution （baicalin+water group） and baicalin PEG400 solution （baicalin+PEG400 group）. After the plasma samples were processed at different time periods， the concentrations of baicalin and B6G in rat plasma were determined by ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）， and pharmacokinetic parameters were processed by DAS 3.2.2 software. Mice were randomly divided into a blank group （normal saline， 20 mL·kg^-1）， aspirin group （dose of 0.2 g·kg^-1）， baicalin/baicalin+PEG400 high and low dose （3.0， 1.5 g·kg^-1） groups， after continuous administration for 7 days， the mouse ear swelling and foot swelling models were established， and the swelling degree and swelling inhibition rate were calculated. Result:The pharmacokinetic study showed that compared with baicalin+water group， the plasma concentrations of baicalin and B6G increased after administration of baicalin PEG400 solution， and the area under the curve （AUC_0-<italic>_t</italic>） increased by 2.36， 1.97 times， and the peak concentration （<italic>C</italic>_max） increased by 2.12， 1.65 times， respectively. The results of mouse ear and foot swelling inflammation models showed that the anti-inflammatory effect was enhanced after intragastric administration of baicalin PEG400 solution. In addition， molecular docking results showed that baicalin and B6G could site bind to multiple target proteins ［tumor necrosis factor （TNF）-<italic>α</italic>， interleukin （IL）-6， IL-1<italic>β</italic>， prostaglandin E₂ （PGE₂） and nuclear transcription factor-<italic>κ</italic>B （NF-<italic>κ</italic>B）］ with higher affinity， which was superior to the positive drug aspirin. Conclusion:PEG400 can increase the plasma concentration of baicalin and its main metabolite B6G， and enhance the anti-inflammatory effect. Baicalin and B6G can form strong hydrogen bonds with various inflammatory factors and of nuclear transcription factors， it is speculated that baicalin and B6G jointly play an anti-inflammatory role.

Green approach toward protection of secondary amine in pyrazole nucleus by PEG-400 and Boc catalyst

The objective of the present study is the protection of secondary amine in the substituted pyrazole derivative withthe help of a green catalyst to facilitate the synthesis of anticancer compounds. Di-tert-butyl dicarbonate (Boc) hasbeen used as a protecting agent with various catalysts such as Polyethylene glycols-400, Dimethyl aminopyridine,and N, N-Diisopropyl ethylamine. In this study, five different synthetic methods have been applied, but success hasbeen achieved in only two. The very first method has been reported for the protection of secondary amine in pyrazole,associated with these catalysts. These synthetic methods had given a good yield and fewer side products, and it also agreen approach toward synthetic chemistry.

Effect of Polyethylene Glycol 400 on Bile Excretion of Baicalin and Its Main Metabolite / 中国实验方剂学杂志

Objective::To investigate the effect of polyethylene glycol 400 (PEG400) on rat bile excretion of baicalin and its main metabolite [baicalein 6-O-β-D-glucuronide (B6G)], and to analyze its mechanism of action. Method::Rats were randomly divided into baicalin+ water group and baicalin+ PEG400 group, the anesthesia was induced by intraperitoneal injection of 10% chloral hydrate (dose of 4 mL·kg-1) to prepare a rat bile duct intubation model. After the rats were fully awake, rats were given baicalin aqueous solution and baicalin PEG400 solution with dose of 168 mg·kg-1 for baicalin, respectively. And bile was collected from 0 h to 12 h after administration. UPLC-MS/MS was used to determine the concentration of drug excreted through bile at different time periods. Thermo Hypersil GOLD C18 column was used with acetonitrile (A)-0.1% formic acid solution (B) as the mobile phase for gradient elution (0-9 min, 90%-27%B; 9-10 min, 27%-90%B; 10-12 min, 90%B), the flow rate was 0.3 mL·min-1, the column temperature was 30 ℃, the injection volume was 5 μL. The mass spectra were obtained in positive ion mode with electrospray ionization (ESI). The effects of PEG400 on the activities and expressions in rat liver of uridine diphosphate glucuronyltransferase (UGT) 1A8 and UGT1A9 were studied in vitro incubation assay and enzyme linked immunosorbent assay (ELISA). Result::Compared with the baicalin+ water group, in the baicalin+ PEG400 group, the bile cumulative excretions of baicalin and B6G increased by 1.8 times and 2.1 times within 12 h, respectively. PEG400 increased the enzyme activities of UGT1A8 and UGT1A9 by 2.0 times and 1.5 times, and their concentrations in liver were increased by 2.2 times and 1.3 times, respectively. Conclusion::PEG400 can significantly increase the bile excretion of baicalin and its main metabolite B6G by enhancing the activities and expressions of UGT1A8 and UGT1A9, and its promoting effect on bile excretion of B6G is greater than that of baicalin, which provides a basis for the rational clinical application of PEG400 and the design of new dosage forms of flavonoids such as baicalin.

Effect of PEG400 on pharmacokinetics of baicalin and baicalein in gut microbiotadysbiosis rats / 中国中药杂志

The study aimed to establish an UPLC-MS/MS method for the determination of baicalin in rat plasma,in order to study the effect of PEG400 on pharmacokinetics of baicalin and baicalein in normal and gut microbiotadysbiosis rats. Plasma was precipitated with ethyl acetate and determined by UPLC-MS/MS method,with genistein as an internal standard. In terms of specificity,linearity,range,accuracy,precision and stability,the method was suitable for the determination of baicalin in plasma. The gut microbiotadysbiosis rat model was induced through the oral administration with lincomycin hydrochloride(5 g·kg-1·d-1) for one week. Samples of plasma of rats were obtained at different time points,after the rats were administrated with baicalin,baicalin and PEG400. Baicalin in rats were detected by UPLC-MS/MS method,and pharmacokinetic parameters were calculated by DAS 3. 2. 2 software. The results showed that the β-glucosidase activity and the number of colonies in the feces of gut microbiotadysbiosis rats induced by lincomycin hydrochloride were significantly reduced. The Cmaxand AUC0-tof the baicalinand PEG400 group in the intestinal flora were significantly lower than those in the normal rat baicalin and PEG400 group. There was no significant difference in Cmaxand AUC0-tbetween the baicalin group and the baicalin+PEG400 group of gut microbiotadysbiosis rats. The Cmaxand AUC0-tof the normal rats baicalin group were significantly higher than those of the gut microbiotadysbiosis rats baicalin group and the baicalin + PEG400 group. There was no significant difference in Cmaxand AUC0-tbetween the normal rat baicalein and PEG400 group and the baicalein group. The Cmaxand AUC0-tof the baicalein group in the gut microbiotadysbiosis rats were lower than those in the normal baicalein group,but significantly higher than those in the baicalein and PEG400 group. PEG400 could increase the absorption of baicalin in normal rats,but is ineffective in gut microbiotadysbiosis rats,with no impact on the absorption of baicalein in rats.

Spectroscopic Characterization of PEG-DNA Biocomplexes by FTIR.

Understanding the mode involved in the binding of certain molecules to DNA is of prime importance, and PEG offers wide-ranging applications in biological, medical and pharmaceutical contexts. FTIR spectroscopy has been used to characterize how the formed biocomplexes bind or dissociate to/from each other between PEG400-ctDNA under different conditions. Characterization and investigation of the effect of incubation time on PEG400-ctDNA biocomplexes formation were studied through spectroscopic technique FTIR. The influence of time duration and incubation on intermolecular interaction was analysed at three different selected times (Zero, 1hr, and 48 hrs.) at 1:1 PEG400-ctDNA monomer to nucleotide ratio. The experiment was carried out at room temperature 22 ºC, with prior vortex stirrer of biocomplex for 10 min to improve homogeneity of sample. The results showed that the binding reaction of PEG400-ctDNA proceeds rapidly through DNA base pairs and phosphate DNA backbone, and complexation was reached after a maximum 1hr after mixing PEG400 and ctDNA at 1:1 ratio. FTIR spectroscopy results suggest that PEG400 binds with ctDNA by weak to moderate biocomplexes formation, with both hydrophilic and hydrophobic contact through DNA base pairs, with minor binding preference towards phosphate backbone of DNA helix. The mode of interaction most likely referred to an interaction through outside groove binding or electrostatic binding modes. FTIR highlighted the significant effect of incubation time on the stable biocomplexes of non-ionic PEG400 and ctDNA. Moreover, FTIR spectroscopy technique was rapid, showed good stability, and is a valuable tool for studying the biological properties of biocomplexes of PEG400 and ctDNA.

Development and Evaluation of self Emulsifying Drug Delivery System for Lornoxicam.

Aim of the present work was to develop and evaluate a solid self-emulsifying drug delivery system (SEDDS) for oral poorly water-soluble drug lornoxicam. The liquid (SEDDS) consisted of capmul MCM as oil phase, tween 20 as surfactant and PEG 400 as co-surfactant. Oil, surfactant and co-surfactant were selected on the basis of solubilisation capacity of drug and emulsification ability of surfactant and co-surfactants. The formulations were optimized by constructing the pseudo-ternary phase diagram. The liquid formulation was solidified by laboratory scale spray dryer, using Aerosil 200 as solid carrier. The solid SEDDS shows greater drug release thus, solid SEDDS improves the oral bioavailability and may provide the useful solid dosage form for oral poorly water soluble drugs.

Extended Hildebrand Solubility Approach applied to Nimodipine in PEG 400 + ethanol mixtures / Método extendido de Hildebrand aplicado a la solubilidad de nimodipina en mezclas PEG 400 + etanol

La nimodipina (NMD) es un agente usado como vasodilatador cerebral y cuyas propiedades fisicoquímicas en solución aún no han sido totalmente estudiadas. En la presente investigación se aplicó el Método Extendido de Solubilidad de Hildebrand (MESH) al estudio de la solubilidad de NMD en algunas mezclas binarias PEG 400 + etanol a 298,15 K. Se obtuvo una capacidad predictiva aceptable del MESH (desviación general inferior al 1,3%) al utilizar un modelo polinómico regular de tercer orden, relacionando el parámetro de interacción W con el parámetro de solubilidad de las mezclas solventes. De esta forma, las desviaciones obtenidas en la solubilidad estimada fueron de magnitud inferior a las obtenidas al calcular esta propiedad directamente, utilizando una regresión empírica regular del mismo orden, de la solubilidad experimental del fármaco en función del parámetro de solubilidad de las mezclas disolventes, en la cual se obtuvo una desviación promedio del 1,7%.

Nimodipine (NMD) is a drug used as cerebral vasodilator whose physicochemical properties in solution have not been studied completely. In this work the Extended Hildebrand Solubility Approach (EHSA) was applied to evaluate the equilibrium solubility of NMD in some polyethylene glycol 400 + ethanol mixtures at 298.15 K. An acceptable correlative capacity of EHSA was found using a regular polynomial model in order three (overall deviation lower than 1.3%), when the W interaction parameter is related to the solubility parameter of the mixtures. Moreover, the mean deviation obtained in the estimated solubility with respect to experimental solubility was lower than the one obtained directly by means of an empiric regression in order three of the logarithm experimental solubility as a function of the mixtures' solubility parameters (1.7%).

Volumetric properties of (PEG 400 + water) and (PEG 400 + ethanol) mixtures at several temperatures and correlation with the Jouyban-Acree model / Propiedades volumétricas de mezclas binarias (PEG 400 + agua) y (PEG 400 + etanol) a diferentes temperaturas y correlación con el modelo Jouyban-Acree

Molar volumes and excess molar volumes were investigated from density values for (PEG 400 + water) and (PEG 400 + ethanol) binary mixtures at temperatures from 283.15 K to 313.15 K. Both systems exhibit negative excess volumes probably due to increased interactions like hydrogen bonding and/or large differences in molar volumes of components. Volume thermal expansion coefficients were also calculated for binary mixtures and pure solvents. The Jouyban-Acree model was used for density and molar volume correlations of the studied mixtures at different temperatures. The mean relative deviations between experimental and calculated density data were 0.1 and 0.5 %, for aqueous and ethanolic mixtures, respectively; whereas, in molar volume data the values were 18.0 and 6.9 %, for aqueous and ethanolic mixtures, respectively. The trained versions of the model for PEG 400 binary solvents could be used to predict the density values of other PEGs with reasonable prediction error employing the density of mono-solvents.

En este artículo se calcularon los volúmenes molares y molares de exceso a partir de valores de densidad para los sistemas PEG 400 + agua y PEG 400 + etanol, en todo el intervalo de composición, a temperaturas entre 283,15 y 313,15 K. Los sistemas estudiados presentan volúmenes de exceso negativos probablemente debido a las fuertes interacciones por unión de hidrógeno entre las moléculas de los dos compuestos y a la gran diferencia en los volúmenes molares de los dos componentes puros. También se calcularon los coeficientes de expansión térmica-volumétrica en los solventes puros y las respectivas mezclas. Asimismo, se usó el modelo Jouyban- Acree para correlacionar la densidad y el volumen molar de las mezclas a las distintas temperaturas. Las desviaciones medias relativas en densidad fueron 0,1% y 0,5% para las mezclas acuosas y etanólicas, respectivamente, mientras que las desviaciones obtenidas para volumen molar fueron 18% y 6,9% para las mezclas acuosas y etanólicas, respectivamente. Los modelos obtenidos para las mezclas binarias con PEG 400 pueden usarse para predecir los valores con otros PEG, con un adecuado margen de error, utilizando las densidades de los solventes puros.

Enhancement of dissolution rate of rapidly dissolving oral film of meclizine hydrochloride by complexation of Meclizine hydrochloride with ß-cyclodextrine.

Motion sickness is a very common disturbance of the inner ear that is caused by repeated motion such as from the swell of the sea, the movement of a car, the motion of a plane in turbulent air, etc. Most medications for motion sickness need to be taken at least 30 minutes prior exposure to the activity that can cause the problem. This project is based on the hypothesis that Mouth Dissolving Films (MDF) are rapidly dissolving dosage forms which when placed in the mouth release the drug immediately. These dosage forms would be preferred by pediatric and geriatric patients since these are not associated with fear of choking. The fast dissolving films prepared by solvent casting method with suitable appearance, mechanical strength, peelability and disintegration time were obtained using Methocel E-5 as a primary film former. Meclizine HCl, a poorly water soluble and bitter drug could be successfully incorporated in the fast dissolving films with the help of solubilizers such as β-Cyclodextrine and PEG-400.