Membranas híbridas de polieterimida-sílice. Caracterización por espectroscopia de IR y MEB.

Se prepararon membranas híbridas de polieterimida-sílice por incorporación de nanopartículas de sílice a la solución polimérica y a través de la generación del relleno inorgánico empleando la técnica sol-gel. Las membranas híbridas obtenidas fueron caracterizadas por FTIR, MEB y MEB-EDS. Los estudios de FTIR permitieron realizar un seguimiento del grado de hidrólisis del alcóxido metálico precursor (TEOS) y analizar la interacción existente entre la sílice generada y el polímero. Las imágenes de MEB reflejaron la evolución de la morfología de las membranas frente a modificaciones producidas durante la síntesis tales como la incorporación de un agente de acoplamiento, la polimerización de TEOS in situ, el incremento del contenido de sílice y el efecto de la redisolución de las membranas sintetizadas. El análisis químico elemental de las membranas híbridas usando EDS, permitió corroborar la presencia de partículas de sílice en las membranas, a través de la observación de la intensidad del pico correspondiente al silicio

Adsorption of Organic Compounds on Activated Carbon Derived from Peanut Shells. Potential Theory Correlation for Estimating Adsorption Capacities and Affinity Coefficients

Adsorption isotherms of eight organic contaminants (acetone, pyridine, phenol, iodine, Methylene Blue, Congo Red, Reactive Navy and tannic acid) onto an activated carbon obtained from peanut shells have been studied at 22°C. The experimental data were analyzed using the Polanyi Potential Theory and the Dubinin–Astakhov equation and collapsed into one general characteristic curve. This analysis allowed the affinity coefficient for each organic compound to be obtained using phenol as the reference substance. A useful correlation for the calculation of the affinity coefficient as a function of relative parachor is presented

Peanut Shell Activated Carbon: Adsorption Capacities for Copper(II), Zinc(II), Nickel(II) and Chromium(VI) Ions from Aqueous Solutions

The adsorption of copper(II), zinc(II), nickel(II) and chromium(VI) ions from aqueous solutions onto an activated carbon produced from peanut shell was studied as a function of the concentration of the ions and the pH value. The amounts of Cu(II), Zn(II) and Ni(II) ions adsorbed increased with increasing equilibrium pH of the solution, while the uptake of Cr(VI) ions decreased. For Cr(VI) ions, maximum uptakes were found at a pH below the point of zero charge of the adsorbent (pH pzc ). The amount of metal cation adsorbed at a given equilibrium concentration increased in the order Ni(II) < Zn(II) < Cu(II). This metal ion uptake order may be explained from a consideration of the combined effects of the electronegativity of the metal ion and the first stability constant of the corresponding metal hydroxide. The activated carbon produced from peanut shell was an effective and economic adsorbent for the removal of metal cations at pH ≥ pH pzc and anions at pH ≤ pH pzc

Solid Dispersions as a Technological Strategy to Improve the Bio-Performance of Antiparasitic Drugs with Limited Solubility

Albendazole (ABZ) and benznidazole (BZL) are drugs with low solubility used in parasitic infections treatment. In this research, solid dispersion (SD) technology was used to enhance ABZ and BZL performance by increasing their dissolution rate and solubility. SDs were prepared by the fusion method, employing Poloxamer 407 (P407) as carrier to disperse 32 of BZL or 50% w/w of ABZ. Furthermore, physical mixtures (PM) of P407 and either ABZ or BZL were also prepared, and then SDs and PMs were characterized. Dissolution tests of SDs, PMs and commercial formulations (CF) of ABZ and BZL were carried out and dissolution profiles were analyzed with the lumped mathematical model, which allowed parameters of pharmaceutical relevance to be obtained. The results indicated that ABZ SD presented an initial dissolution rate (IDR) 21-fold and 11-fold faster than PM and CF, respectively, while the IDR of BZL SD was 2.5-fold and 4.5-fold faster than PM and CF, respectively. For BZL formulations, the time required to reach 80% dissolution of the drug (t80%) was 4 (SD), 46 (PM), and 239 min (CF), while the dissolution efficiency (DE) at 30 min was 85 (DS), 71 (MF) and 65% (FC). For ABZ formulations, t80% was 2 (SD), value not reached (PM) and 40 min (CF), while the DE at 30 min was 85 (SD), 36 (MF) and 65% (CF). The SDs developed notably increased the dissolution rate, in consonance with the values obtained from the pharmaceutical parameters, which could lead to faster absorption and, consequently, increase the bioavailability of these drugs

Sustained-release hydrogels of ivermectin as alternative systems to improve the treatment of cutaneous leishmaniasis

Leishmaniasis is a neglected tropical disease and its cutaneous form manifests as ulcers or nodules, generally in exposed parts of the body. This work aimed to develop ivermectin (IVM) thermosensitive hydrogels as topical formulations to improve cutaneous leishmaniasis treatment. Materials & methods: Hydrogels based on poloxamers 407 and 188 with different concentrations of IVM were prepared and rheologically characterized. The IVM release profiles were obtained and mathematically analyzed using the Lumped model. Results: The formulation containing 1.5% w/w of IVM presented an adequate gelling temperature, an optimal complex viscosity and elastic modulus. Hydrogels allowed to modulate the release of IVM. Conclusion: IVM thermosensitive hydrogels can be considered a valuable alternative to improve the treatment of cutaneous leishmaniasis.Fil: Romero, Analía Irma. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería; ArgentinaFil: Cid, Alicia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería; ArgentinaFil: Minetti, Nicolás E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería; ArgentinaFil: Briones Nieva, Cintia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería; ArgentinaFil: Garcia Bustos, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Gonzo, Elio Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería; ArgentinaFil: Villegas, Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería; ArgentinaFil: Bermudez, Jose Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería; Argentin