scholarly journals An Alcohol-Free SiO2Sol-Gel Matrix Functionalized with Acetic Acid as Drug Reservoir for the Controlled Release of Pentoxifylline

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mayra Angélica Alvarez Lemus ◽  
Oscar Javier Ortiz Castañeda ◽  
Alma Delia Hernández Pérez ◽  
Rosendo López González
Keyword(s):  
Acetic Acid ◽  
Controlled Release ◽  
Sol Gel ◽  
Spectroscopic Characterization ◽  
Xanthine Derivative ◽  
Bet Specific Surface Area ◽  
Sol Gel Process ◽  
Drug Reservoir ◽  
Uv Visible ◽  
High Doses

Pentoxifylline (PTX) is a xanthine derivative, with hemorrheologic properties, that has been useful in the treatment of several diseases. However, a conventional route of administration implies high doses, what is unnecessary to the organism, seriously increasing the risk of toxicity because of side effects. Because of the facility to modify their surface, sol-gel materials have proved to be suitable reservoirs for a variety of molecules for biological applications. In this work we prepared alcohol-free SiO2material by the sol-gel process using acetic acid as surface modifier and hydrolysis catalyst, the alkoxide/water ratio (Rw) used was 1/16, and tetraethylorthosilicate was used as SiO2precursor. Spectroscopic characterization was carried out by means of FTIR-ATR and UV-Visible spectroscopies; the results confirmed the presence of the drug and interactions between sol-gel matrix and PTX. BET specific surface area values of the sol-gel materials were 365 and 462 m2/g for SiO2and PTX-SiO2, respectively. Synthesized SiO2nanoparticles showed efficient entrapment of PTX since a controlled release of 83% of drug content was reached.

Controlled release of glibenclamide from monolithic silica subdermal implants produced by the sol-gel process and its use for hyperglycaemia treatment in a murine model

2019 ◽  
Vol 94 ◽  
pp. 1009-1019 ◽  
Author(s):  
Vicente Jesús Hernández-Abad ◽  
Elizabeth Guadalupe Sánchez-González ◽  
Cynthia Espinosa-Contreras ◽  
Rubén Marroquín-Segura ◽  
José Luis Alfredo Mora-Guevara ◽  
...  
Keyword(s):  
Controlled Release ◽  
Murine Model ◽  
Sol Gel ◽  
Monolithic Silica ◽  
Sol Gel Process ◽  
Subdermal Implants

scholarly journals Synthesis and Functionalization of a Mesoporous Silica Nanoparticle Based on the Sol—Gel Process and Applications in Controlled Release

ChemInform ◽  
2007 ◽  
Vol 38 (50) ◽  
Author(s):  
Brian G. Trewyn ◽  
Igor I. Slowing ◽  
Supratim Giri ◽  
Hung-Ting Chen ◽  
Victor S.-Y. Lin
Keyword(s):  
Controlled Release ◽  
Mesoporous Silica ◽  
Sol Gel ◽  
Silica Nanoparticle ◽  
Mesoporous Silica Nanoparticle ◽  
Sol Gel Process

Microencapsulation of Oil in Organically Modified Silicate Glass by Sol-Gel Process

2002 ◽  
Vol 726 ◽  
Author(s):  
Sang I. Seok ◽  
Bok Y. Ahn ◽  
Joo H. Kim ◽  
Tae S. Suh
Keyword(s):  
Controlled Release ◽  
Sol Gel ◽  
Microemulsion System ◽  
Processing Parameter ◽  
Active Core ◽  
Spherical Silica ◽  
Sol Gel Process ◽  
Organically Modified ◽  
Oil Mixtures ◽  
Silica Precursor

AbstractMicroencapsulation provides protection and sustained or controlled release of active core agents. The sol-gel process has opened up a new way for encapsulating oil droplets within an inorganic capsule. Silica microcapsules were prepared in silica precursor-oil mixtures/NH4OH water microemulsion system. In this step, the formation of capsules incorporating oil depended strongly on the type of silica precursor. A spherical silica microsheres were only obtained when oligomer, synthesized by the hydrolysis and co-condensation of equiweight of TEOS (tetraethylorthosilicate) and MTMS (methyltrimethoxysilane), was used as the wall materials. The particles size of silica microcapsules was in the range of 1 ∼ 100 μm, depending on processing parameter such as a shear rate and O/W ratio etc. In controlled release system, the shell porosity is important to give an appropriate permeability, corresponding to the release rate. The pore structure, responsible for permeability, was adjusted by doping alkyl silane, and investigated with nitrogen sorption measurement.

scholarly journals Synthesis and Functionalization of a Mesoporous Silica Nanoparticle Based on the Sol–Gel Process and Applications in Controlled Release

2007 ◽  
Vol 40 (9) ◽  
pp. 846-853 ◽  
Author(s):  
Brian G. Trewyn ◽  
Igor I. Slowing ◽  
Supratim Giri ◽  
Hung-Ting Chen ◽  
Victor S.-Y. Lin
Keyword(s):  
Controlled Release ◽  
Mesoporous Silica ◽  
Sol Gel ◽  
Silica Nanoparticle ◽  
Mesoporous Silica Nanoparticle ◽  
Sol Gel Process

Sol-Gel Process from Heterobimetallic Alkoxides to Incorporate Lanthanides in an Alumina Matrix

1992 ◽  
Vol 271 ◽  
Author(s):  
Chaitanya K. Narula
Keyword(s):  
Acetic Acid ◽  
Structural Changes ◽  
Sol Gel ◽  
Alumina Matrix ◽  
Slow Evaporation ◽  
Thermally Induced ◽  
Excess Water ◽  
Sol Gel Process ◽  
Amorphous Powders ◽  
Hydrolysis Of

ABSTRACTGels form on addition of seven or more moles of water diluted withi-PrOH to one mole of M[Al(O-i-Pr)4]3, M = La, Ce dissolved in i-PrOH. Thermal treatment of xerogels derived from La[AI(O-i-Pr)4]3gives amorphous powders below 900°C. LaAIO3crystallizes out at 900°C and residual alumina remains amorphous. CeO2starts to separate out above 600°C from the xerogels prepared from Ce[M(O-i-Pr)4]3. Thermally induced structural changes in xerogels prepared from the mixtures of La[AI(O-i-Pr)4]3and Ce[AI(0-i-Pr)4]3in 1:1 or 1:3 ratio are different from those prepared from individual precursors. These xerogels remain amorphous below 700°C. Crystalline CeO2forms on heating at 900°C but alumina remains amorphous. Sols are formed on hydrolysis of M[AI(0-/-Pr)4]3in excess water and acidifying the reaction mixture with acetic acid. Sols can be converted to gels by slow evaporation of volatiles. This method is useful in preparing coatings.

scholarly journals Synthesis and Optical Characterization of Mg1-xNixO Nanostructures

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Nageswararao Budiredla ◽  
Ashok Kumar ◽  
Subhash Thota ◽  
Jitendra Kumar
Keyword(s):  
Energy Levels ◽  
Sol Gel ◽  
Nickel Content ◽  
Lattice Parameter ◽  
Weak Band ◽  
Optical Absorbance ◽  
Bet Specific Surface Area ◽  
Sol Gel Process ◽  
Defect Centres

An attempt has been made here to synthesize nano-powders via sol-gel process. These powders are shown to possess an f.c.c. (NaCl-type) structure with a typical lattice parameter of  Å for when decomposition of dried oxalate gel product is carried out at 600°C for 2 h in air. Moreover, they exhibit (i) clusters/agglomerates of nanosize particles and (ii) high BET specific surface area (123.0–135.5 m2/g). Also, the infrared absorption spectra reveal their strong affinity to water. The UV-Vis absorption peaks appearing at ~202 nm, 296 nm, and 379 nm are associated with oxygen defect centres and correspond to the electronic transitions (i) (, , or ), (ii) (, or ) and (iii) (), respectively. The incorporation of Ni2+ ions causes some modifications in the energy levels and the optical absorbance characteristics. The suppression of a strong broad emission peak at 440 nm and improvement of a weak band at 400 nm in the photoluminescence (PL) spectrum arise due to decrease in population density of centres (or F+ dimmers) and emergence of additional F+ centres, respectively with increase in nickel content.

Production of Spherical Powders of Inorganic Compounds by Water Extraction Variant of Sol-Gel Process

1992 ◽  
Vol 271 ◽  
Author(s):  
A. DeptuLa ◽  
J. Rebandel ◽  
W. Drozda ◽  
W. Lada ◽  
T. Olczak
Keyword(s):  
Acetic Acid ◽  
Pilot Plant ◽  
Inorganic Compounds ◽  
Sol Gel ◽  
Water Extraction ◽  
Salt Solutions ◽  
Sol Gel Process ◽  
Span 80 ◽  
Starting Solutions

ABSTRACTA method of preparation of spherical powders (with particle diameters <100µm) of metal oxidcs, their homegeneous mixtures or compounds, composites and metals has been elaborated. Depending on the nature of cations, the starting solutions were prepared by extraction of anions with Primene JMT from salt solutions, by addition of dopants to the sols or by complexing with acetic acid or/and ammonia. The sols or broths were then emulsified in 2-ethyl-l-hexanol containing SPAN 80. Drops of the emulsion were solidified by extraction of water with the solvent. The process was carried out continuously in a laboratory and/or in a pilot plant.

Acetic Acid in Sol-Gel Process of Hydrolytic Polycondensation of Tetramethoxysilane

2004 ◽  
Vol 77 (2) ◽  
pp. 290-294 ◽  
Author(s):  
N. N. Khimich ◽  
B. I. Venzel' ◽  
L. A. Koptelova ◽  
I. A. Drozdova
Keyword(s):  
Acetic Acid ◽  
Sol Gel ◽  
Hydrolytic Polycondensation ◽  
Sol Gel Process
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