Development and pharmacological evaluation of in vitro nanocarriers composed of lamellar silicates containing copaiba oil-resin for treatment of endometriosis.

In this work, newly developed nanocomposites based upon lamellar silicates are evaluated to determine their potential in controlling endometriosis. The preparation of the new nanocarriers is detailed, properties characterized and in vitro pharmacological evaluation performed. The nanocomposites in this study were obtained from the reaction of copaiba oil-resin (COPA) with the polymer polyvinylpyrrolidone (PVP K-30). COPA was selected due to its antiinflammatory and anticancer activities along with the organophilic derivatives of sodium montmorillonite, Viscogel B8, S7 and S4. The results indicated that it was feasible to obtain a good yield of a COPA nanocomposite using a simple process. Intercalation was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). In vitro release experiments demonstrated that COPA was released from the nanocomposite in a delayed fashion. Whereas, in vitro pharmacological studies showed a reduction in viability and proliferation of endometriotic cell cultures upon COPA nanocomposite treatment, suggesting that the system developed here can be a promising alternative therapy for the oral treatment of endometriosis.

Síntesis de matrriales microcompuestos de poliailina/arcilla: caracterización y evaluación de su actividad como agentes anticorrosioos / Synthesi of polyyanilineclay microcomposite materials: characterizationn and assessment of its activity as anticorrosive agetss / Síntese d materiiais micro-compostos de polianilina/argila: caracterização e avaliação da sua atividade como agentes anti-corossivos

En el presente trabajo se realiza la síntesis de materiales “microcompuestos” a partir de polianilina en su forma esmeraldina base y dos montmorillonitas colombianas. Las arcillas naturales fueron sometidas a intercambio catiónico con una sal de amonio cuaternaria para obtener arcillas organofílicas que posteriormente fueron modificadas con polianilina mediante polimerización oxidativa in situ. La caracterización de los sólidos mediante espectroscopía infrarroja (FT-IR), difracción de rayos X (DRX), SEM y DSC evidencia la síntesis exitosa de los materiales mediante intercalación o delaminación de los minerales de arcilla. Los sólidos sintetizados se evaluaron como agentes anticorrosivos mediante mediciones electroquímicas de potencial de corrosión, resistencia de polarización y corriente de corrosión sobre electrodos de acero cold-rolled 1020 (AISI-SAE). Se encontró que los microcompuestos sintetizados brindan protección a la superficie del acero contra los agentes corrosivos, obteniendo diferencias significativas entre los materiales microcompuestos de polianilina/ arcilla, sin que éstos superen el potencial anticorrosivo de la polianilina en su forma esmeraldina base pura.

In the present work microcomposites-materials from polyaniline as emeraldine- base and two Colombian montmorillonites were synthesized. The natural clays were subjected to cationic exchange with an ammonium quaternary salt in order to obtain organophilic clays to be modified with polyaniline by an “in situ” oxidative polymerization. Characterization by infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), SEM and DSC reveals the successful synthesis of materials by means of intercalation or delamination of the clay minerals. The synthesized solids were assessed as anticorrosive agents by electrochemical measurements of corrosion potential, polarization resistance and corrosion current on electrodes of cold-rolled 1020 (AISI-SAE) steel. It was found that the synthesized microcomposites provide protection to the surface of steel against corrosive agents, obtaining in this way important difference between the microcomposites materials of polyaniline/ clay, without they can surpass the anticorrosive potential of the polyaniline in the pure emeraldine-base form.

No presente trabalho realizou-se a síntese de materiais “micro-compostos” a partir de polianilina em sua forma esmeraldina base e duas montmorillonitas colombianas. As argilas naturais foram submetidas a intercâmbio catiónico com uma sal da amônia quaternaria para obter argilas organofílicas que foram modificadas posteriormente com polianilina mediante polimerização oxidativa “in situ”. A caracterização dos sólidos mediante espectroscopia de absorção na região de infravermelho (FT-IR), difração de raios X (DRX), microscopia eletrônica de varredura (SEM) e DSC evidência a síntese exitosa dos materiais mediante intercalação ou elaminação dos minerais da argila. Os sólidos sintetizados foram avaliados como agentes anti-corrosivos mediante medidas eletroquímicas do potencial da corrosão, resistência do polarização e corrente da corrosão sobre elétrodos de aço cold-rolled 1020 (AISI-SAE). Encontrou-se que os micro-compostos sintetizados oferecem proteção à superfície do aço contra os agentes corrosivos, obtendo-se diferenças importantes entre os materiais micro-compostos de polianilina/ argila, sem que estes superem o potencial anti-corrosivo da polianilina em sua forma esmeraldina base pura.

Effect of clays on the fire-retardant properties of a polyethylenic copolymer containing intumescent formulation.

Organophilic clay particles were added to a standard intumescent formulation and, since the role of clay expansion or intercalation is still a matter of much controversy, several clays with varying degrees of interlayer distances were evaluated. The composites were obtained by blending the nanostructured clay and the intumescent system with a polyethylenic copolymer. The flame-retardant properties of the materials were evaluated by the limiting oxygen index (LOI), the UL-94 rating and thermogravimetric analysis (TGA). The results showed that the addition of highly expanded clays to the ammonium polyphosphate and pentaerythritol formulation does not significantly increase the flame retardancy of the mixture, when measured by the LOI and UL-94. However, when clays with smaller basal distances were added to the intumescent formulation, a synergistic effect was observed. In contrast, the simple addition of clays to the copolymer, without the intumescent formulation, did not increase the fire retardance of the materials.