Mineralogical transformations due to salt whitening agent in modern Hebron ceramics

2022 ◽  
Vol 41 ◽  
pp. 103303
Author(s):  
L. Teodorescu ◽  
N. Cantin ◽  
A. Ben Amara ◽  
R. Chapoulie ◽  
V. Roux
Keyword(s):  
1996 ◽  
Vol 61 (3) ◽  
pp. 333-341
Author(s):  
Jiří Barek ◽  
Roman Hrnčíř ◽  
Josino C. Moreira ◽  
Jiří Zima

The polarographic behaviour was studied for 6-β-D-glucopyranosyloxy-7-hydroxycoumarin, a natural compound serving as an optical whitening agent. The substance can be quantitated by tast polarography, differential pulse polarography using a conventional dropping mercury electrode, and differential pulse polarography using a static mercury drop electrode over the regions of 20-1 000, 2-1 000, and 0.2-1 000 μmol l-1, respectively. The methods developed for the quantitation of the compound were applied to its direct determination in a raw product.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 449
Author(s):  
Siriporn Okonogi ◽  
Adchareeya Kaewpinta ◽  
Pisaisit Chaijareenont

Carbamide peroxide (CP), a tooth whitening agent, is chemically unstable. The present study explores stability enhancement of CP by loading in a nanofibrous film (CP-F) composed of polyvinyl alcohol/polyvinylpyrrolidone/silica mixture, using an electrospinning technique. Kept at a temperature range of 60–80 °C for 6 h, CP in CP-F showed significantly higher stability than that in a polymer solution and in water, respectively. Degradation of CP in CP-F could be described by the first order kinetics with the predicted half-life by the Arrhenius equation of approximately 6.52 years. Physicochemical properties of CP-F after long-term storage for 12 months at different temperatures and relative humidity (RH) were investigated using scanning electron microscopy, X-ray diffractometry, differential scanning calorimetry, and Fourier transform infrared spectroscopy. It was found that high temperature and high humidity (45 °C/75% RH) could enhance water absorption and destruction of the nanofibrous structure of CP-F. Interestingly, kept at 25 °C/30% RH, the nanofibrous structure of CP-F was not damaged, and exhibited no water absorption. Moreover, the remaining CP, the mechanical properties, and the adhesive properties of CP-F were not significantly changed in this storage condition. It is concluded that the developed CP-F and a suitable storage condition can significantly improve CP stability.


Author(s):  
Framesti Frisma Sriarumtias ◽  
Nurul Auliasari

<p class="abstract"><strong>Background:</strong> Indonesia is a tropical country that is exposed to the sun for 12 hours, one of the harm effects of sunlight which is damage to the skin. The purpose of this study was to determine tyrosinase inhibition of tangerin peel extract (<em>Citrus reticulata Blanco</em>.) from Garut, West Java, Indonesia then develop the splash mask from the extract.</p><p class="abstract"><strong>Methods:</strong> The tangerine peel will be extracted by maceration method. The splash mask formulation containing tangerine peel extract which has a whitening agent. Tyrosinase inhibition determine by ELISA method with tyrosinase enzyme and L-DOPA substrat.<strong></strong></p><p class="abstract"><strong>Results:</strong> The results showed that tangerine peel extract had tyrosinase inhibition with the IC50 of 30.000 ppm, which has less effective than kojic acid with IC50 81,10 ppm. Splash mask containing of 1000x IC50, evaluation carried out for 28 days showed that preparations made pharmaceutically stable.</p><p class="abstract"><strong>Conclusions:</strong> In addition, the whitening agent of tangerine peel extract is in the weak category. It is hoped that this research can increase the value of tangerine peel waste.</p><p> </p>


2011 ◽  
Vol 183-185 ◽  
pp. 1692-1695
Author(s):  
Wen Hua Gao ◽  
Ke Fu Chen ◽  
Ren Dang Yang ◽  
Fei Yang ◽  
Xiao Bin Chen

Fluorescent whitening agent is relatively small dosage in the coating, but it has great influence on the properties of the coating and ink-jet printing qualities. With the increase of fluorescent whitening agent dosage, the PH of the coating rose but the viscosity was hardly to change. The brightness of coated ink-jet printing paper and color density of the printing image firstly presented the trend of increasing then decreasing. What’s more, when the brightness of the coated paper achieved to the maximum, color density and contact angle properties were the largest. Chromatic aberration property of the image reduced from 1.87 to 1.75, when the addition of fluorescent whitening agent rose from 0.1% to 0.5%. While the dosage was rose to 0.9%, chromatic aberration increased to 2.15. The gloss of coated paper decreased with the dosage of fluorescent whitening agent increasing. In sum, fluorescent whitening agent can enhance the brightness of the coated paper as well as the printing properties. The results show that the best brightness and printing qualities of coated ink-jet printing paper are obtained, when the fluorescent whitening agent is 0.5%( relative to pigment).


2017 ◽  
Vol 1 (2) ◽  
pp. 121
Author(s):  
Husnul Warnida

Bengkuang roots (Pachyrhizus erosus (L.) Urb.)  empirically have been used as cosmetics materials, primarily as sun screen and whitening agent. Bengkuang roots posses 6 compound which have tyrosinase inhibitory activities. Commercially, bengkuang roots available as whitening cream and lotion but those dosage forms are not suitable for oily skin. In this study the gel was formulated with varying methylcellulose (4% and 5%) as gelling agent. The evaluation included stability, organoleptic, pH, homogeneity, and spreading test. Formula A (4% methylcellulose) meets all physical requirements of gel. The result of acceptability (hedonic test. showed the most acceptance formula was formula A (4% methylcellulose).


Author(s):  
SILVIA SURINI ◽  
NUR MPN NEGORO

Objective: In addition to lactic acid and sodium ascorbyl phosphate, which have whitening effects, beta-arbutin is a safe whitening agent for skin.Combining these three substances should reduce the concentration of each one in a formula and achieve an optimal whitening effect. In this study,microemulsions and water/oil/water (W/O/W) multiple emulsions were applied to produce a formula containing these whitening agents.Methods: All the active ingredients were formulated into microemulsions and W/O/W multiple emulsions with different concentrations of Tween 80and Span 80 as emulsifiers to obtain a stable formula. Twelve-week physical stability studies were performed for every formula at low (4±2°C), room(28±2°C), and high (40±2°C) temperatures.Results: The produced microemulsions were transparent with a mean droplet size of 15.50 nm. In addition, the W/O/W multiple emulsions containeddroplets within droplets, which were dispersed in a continuous phase with an inner droplet size of 0.15 μm and an outer droplet size of 0.37 μm. TheW/O/W multiple emulsions showed pseudoplastic thixotropic flow properties. Furthermore, the microemulsions were stable at low (4±2°C) androom (28±2°C) temperatures, while the W/O/W multiple emulsions were stable at room (28±2°C) and high (40±2°C) temperatures.Conclusion: It was concluded that the combination of beta-arbutin, lactic acid, and sodium ascorbyl phosphate was suitable for formulating intomicroemulsions as well as W/O/W multiple emulsions as whitening cosmetic products.


Jurnal Kimia ◽  
2019 ◽  
pp. 207
Author(s):  
K. D. Adnyani ◽  
L. W. E. Lestari ◽  
H. Prabowo ◽  
P. A. I. A. Siaka ◽  
N. P. L. Laksmiani

Increasing melanogenesis process causes excessive melanin synthesis resulting in darkening of the skin color. The melanogenesis process requires mealnogenesis enzymes, one of which is tyrosinase-related protein 1. One of the flavonoid compounds that has the potential as a skin lightening agent is quercetin. The antioxidant activity of quercetin plays a very important role in antimelanogenesis. This study aims to determine the affinity and molecular mechanism of quercetin on the target protein tyrosinase-related protein 1 using in silico molecular docking method. Molecular docking is carried out through stages including optimization of the structure of quercetin compounds, preparation of the target protein tyrosinase-related protein 1, validation of the molecular docking method, and docking of quercetin on the tyrosinase-related protein 1. Docking of quercetin with tyrosinase-related protein 1 produces binding energy values of -7.81 kcal/mol, while docking of native ligand with tyrosinase-related protein 1 produces binding energy values of -5.39 kcal/mol. Quercetin has a strong affinity for tyrosinase-related protein 1 which is indicated by the binding energy from the docking results. Quercetin has activity as a skin whitening agent with in silico test with molecular mechanisms through inhibition of the activity of tyrosinase-related protein 1 enzyme.  Keywords: skin whitening agent, in silico, quercetin, tyrosinase-related protein 1


2019 ◽  
Vol 24 (1) ◽  
pp. 76-84
Author(s):  
Birendra Kumar Singh ◽  
Eun-Ki Kim

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