Montmorillonite-Rifampicin Nanohybrid for pH-Responsive Release of the Tuberculostatic.

The present work describes the development of a hybrid and pH-responsive system for rifampicin using the clay mineral 'montmorillonite' as a nanocarrier. The influence of operational variables on the drug incorporation process was evaluated using 24 factorial designs. Under optimized conditions, the experiment allowed an incorporated drug dose equivalent to 98.60 ± 1.21 mg/g. Hybrid systems were characterized by different characterization techniques (FTIR, XRD, TGA, DSC, and SEM) to elucidate the mechanism of interaction between the compounds used. Through in vitro release studies, it was possible to verify the efficacy of the pH-dependent system obtained, with approximately 70% of the drug released after sixteen hours in simulated intestinal fluid. The adjustment of the experimental release data to the theoretical model of Higuchi and Korsmeyer-Peppas indicated that the release of rifampicin occurs in a prolonged form from montmorillonite. Elucidation of the interactions between the drug and this raw clay reinforces its viability as a novel carrier to develop an anti-TB/clay hybrid system with good physical and chemical stability.

Experimental design for optimization of the photocatalytic degradation process of the remazol red dye by the TiO2/expanded perlite composite.

In this study, the photocatalytic decolorization of remazol red dye (RR) was evaluated using TiO2 based composites supported on the expanded perlite (T-EP-10% and T-EP-30%). The characterization techniques used in this work were IR, XRD, XRF and particle size analysis. In order to optimize the RR discolouration process, a factorial planning was applied. The best experimental conditions are the RR initial concentration of 10 mg L-1, composite T-EP-30% and both PHs showed positive results in the decolorization. The tests performed at pH 2.0 showed 100% removal of RR colour in 180 min and at pH 5.0 100% colour removal was obtained in 120 min. The decolorization process follows a pseudo first-order-kinetics, the kapp of 0.01191 min-1 for the tests at pH 5.0 and 0.00812 min-1 for the tests at pH 2.0. The results of energy cost shown that in both pH 2.0 and 5.0 tests were feasible in efficiency and economically. The energy consumption for the test at pH 2.0 was 0.297 kWhdm3 and final cost of R$ 0.163, while the energy consumption for the test at pH 5.0 was 0.198 kWhdm3 and a final cost of R$ 0.111.

pH-responsive release system of topiramate transported on silica nanoparticles by melting method.

Incorporating drugs into silica matrices by the melting method can be applied to obtain drug delivery systems because they are governed by electrostatic type interactions, hydrogen bonding and hydrophilic-hydrophobic interactions between the drug and the silica surface. the melting method is an environmentally correct tool since it is free of organic solvent, low cost and with easy execution for the incorporation of drugs in silicas. Drugs delivery systems are very important for improving the treatment of chronic diseases. Topiramate (TPM) is a potent antiepileptic used in high daily doses as it has low bioavailability. In this context, silica nanoparticles (NPS) were used as an inorganic matrix for TPM transport in (in vitro) release studies. The TPM was incorporated into the NPS by hot melt loading employing a new carrier preparation methodology (NPS/TPM) using a thermobalance (by Thermogravimetry-TG) with high temperature control system. The release study using dissolution media simulating gastrointestinal at pH 1.2 (stomach) and 7.4 (intestine), showed that NPS release TPM in a prolonged and pH-responsive manner. The drug was released at intestinal pH ensuring greater absorption, allowing fewer daily doses and less adverse effects. The kinetic study demonstrated the best fit to the zero-order model proving the pH-responsive profile of the developed system.

Obtaining and Applying Nanohybrid Palygorskite-Rifampicin in the pH-Responsive Release of the Tuberculostatic Drug.

Despite having good efficacy in the treatment and prevention of tuberculosis, the administration of rifampicin (RIF) can cause serious side effects, resulting from the prolonged use of this substance. Thus, it is necessary to seek new systems for administering tuberculostatic drugs, to avoid unwanted adverse effects, increase their bioavailability and, consequently, improve their therapeutic efficacy. The present work describes the achievement of a pH-responsive system for RIF, using palygorskite, a fibrous clay mineral, as a nanocarrier. To evaluate the influence of some operational variables on the drug adsorption process, a 24 factorial experimental design was used. The experiment using a maximum concentration (0.125 mg/mL), lower mass of PAL (300 mg), and lower pH (pH 2) was more efficient compared to other experiments, resulting in a higher dose of the incorporated drug, equivalent to 33.62 mg/g. To elucidate the mechanism of interaction between the materials, the hybrid obtained was characterized by different characterization techniques (Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry/derived thermogravimetry, zeta potential, scanning electron microscopy, and dispersive energy spectroscopy). In addition, kinetic models and adsorption isotherms were applied to the experimental data. Through in vitro release studies, it was possible to verify the effectiveness of the pH-dependent system obtained. The adjustment of experimental release data to the theoretical model of Higuchi indicated that the release of rifampicin occurs in a prolonged way from the palygorskite.