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Thickening Agents
Published in Heather A.E. Benson, Michael S. Roberts, Vânia Rodrigues Leite-Silva, Kenneth A. Walters, Cosmetic Formulation, 2019
Ricardo D’Agostino Garcia, Antony O’Lenick, Vânia Rodrigues Leite-Silva
Fumed silica is a synthetic, amorphous, colloidal silicon dioxide. It is an inorganic thickener with a wide variety of cosmetics and personal care applications. With fumed silica, cosmetic oils can easily be converted into highly viscous, largely transparent gels. There are some modified silica with hydrophobic properties which are perfect for creating or adjusting thixotropic properties, improving suspension without significantly increasing viscosity, and imparting stability and water-resistance to emulsions, especially for sunscreen and makeup formulations.
Etoposide encased folic acid adorned mesoporous silica nanoparticles as potent nanovehicles for enhanced prostate cancer therapy: synthesis, characterization, cellular uptake and biodistribution
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Seema Saroj, Sadhana J. Rajput
MCM-41 mesoporous silica nanoparticles were synthesized based on template synthesis method with few alterations [15,16]. For the fabrication of MSNs, 2.21 grams (g) of CTAB playing a role of the structural template was dissolved in de-ionized water and blended for 5 min (min). 3.24 millilitres (mL) of TMAOH was added to the reaction blend dropwise under continuous magnetic stirring. Later, 3 g fumed silica was added after a time interval of 10 min. Finally, this was subjected to hydrothermal treatment for 48 h at 383 K. The slurry obtained was filtered and dried appropriately. The asynthesized MSNs obtained in the form of dry powder were subjected to calcination at 823 K for 6 h to completely evacuate the template. Further, the calcinated MSNs were added to toluene in an RBF followed by addition of APTS at 70 °C for 12 h. After the reaction was complete, it was allowed to cool at RT and then filtered, followed by thorough washing with methanol and complete drying [16,17]. The product was marked as A@MSN.
Tailor-made pH-sensitive polyacrylic acid functionalized mesoporous silica nanoparticles for efficient and controlled delivery of anti-cancer drug Etoposide
Published in Drug Development and Industrial Pharmacy, 2018
Seema Saroj, Sadhana J. Rajput
MCM-41 was synthesized hydrothermally as per the literature reported method via template synthesis mechanism with slight modifications [28]. Accurately weighed, 4.42 grams (g) CTAB was added to 33 milliliters (mL) of de-ionized water and stirred for 5 minutes (min). To this, 6.52 ml of TMAOH was added dropwise to the reaction mixture under continuous stirring. After elapsing of 10 min, 6 g of fumed silica was added. Reaction mixture was kept under continuous stirring for 2 h. Subsequently, hydrothermal treatment was given for 48 h. The thick white slurry was filtered, washed with de-ionized water thoroughly and dried. Consequently, the structure template CTAB was completely detached by calcination at 823 K for 5 h. The fine product MCM-41 was obtained and further confirmed by characterization using infrared spectroscopy (IR) and low angle X-Ray diffraction studies (LXD).
Clinical pharmacokinetic study for the effect of glimepiride matrix tablets developed by quality by design concept
Published in Drug Development and Industrial Pharmacy, 2018
Tarek A. Ahmed, Mohammad A. A. Suhail, Khaled M. Hosny, Fathy I. Abd-Allah
Fumed silica, also known as pyrogenic silica because it is produced in a flame, consists of microscopic droplets of amorphous silica fused into branched, chain-like, three-dimensional secondary particles that then agglomerate into tertiary particles. The resulting powder has an extremely low-bulk density (BD) and high surface area. Its three-dimensional structure results in viscosity-increasing, thixotropic behavior when used as a thickener or reinforcing filler. Fumed silica exerts a very strong thickening effect. Its primary particle size is 5–50 nm. The particles are non-porous and have a surface area of 50–600 m2/g. The density is 160–190 kg/m3 [4]. Fumed silica serves as a universal an anticaking agent (free-flow agent) in powders. The adsorption of drug on the surface of fumed silica aids in the dissolution process due to its higher surface area [5].