A magnetic resin based on lignin produced using the Kraft process was prepared and characterized. The material, because of its aromatic/aliphatic balance, can be used in oil-spill clean-up processes. The resin was prepared through bulk polycondensation of lignin, cashew nutshell liquid, and formaldehyde in the presence of maghemite nanoparticles. The obtained magnetic composites were studied by Fourier transform infrared spectroscopy, X-ray diffraction, and Small-angle X-ray scattering. Cure degree, magnetic force, and oil removal capability tests were also performed. The results show that the composites possess an elevated cure degree, besides a considerable magnetic force. The materials exhibit a good oil removal capability-the composite containing 3.3 vol % of maghemite can remove 11 parts of oil from water. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 126: E304-E311, 2012

The antibiotic cotrimoxazole was associated with poly(lactic acid-co-glycolic acid) (PLGA) and maghemite, aiming to reach a controlled drug release system. PLGA was synthesized through the polycondensation of lactic acid and glycolic acid in an equimolar ratio, and maghemite was synthesized through the coprecipitation method. The drug cotrimoxazole was inserted in the composite through three different procedures: solution, fusion, and in situ to check the best insertion method. Several techniques were used to characterize the materials. The copolymer was characterized by nuclear magnetic resonance and size-exclusion chromatography. In addition, the maghemite, the composites containing the drug, and the polymer were characterized by Fourier transform infrared spectroscopy (FTIR) with attenuated total reflectance device, small-angle X-ray scattering, and magnetic force, this last according to the methodology developed by our group. The root mean square error was used to compare the FTIR spectra of the samples, proving that the fusion method was the best way to insert the drug and maghemite in the polymer. Therefore, composites containing the drug and the nanoparticles were prepared by the fusion method. These composites were used for dissolution profile studies, which were monitored with and without magnetic field, aiming to understand the influence of the magnetic field on the dissolution profile. The dissolution was monitored and quantified using the ultraviolet-visible spectrophotometry, following the United States Pharmacopeia (USP) method for cotrimoxazole tablets. Results demonstrated that nanocomposites presented a good magnetic force, able to keep the magnetic composite trapped in a specific place or tissue. The presence of the nanoparticles in the composites changed the kinetics of the drug release, as they constitute physical barriers to the drug diffusion, contributing to a sustained drug release process. Furthermore, in the presence of a magnetic field, the magnetic nanoparticles were able to perform a magnetic constriction of the material, making the drug release faster than in the absence of the magnetic field, which may be useful to perform a fine tuning of the system, allowing the easier adjustment of the speed and amount of released drug, useful to improve medical treatments and even the welfare of the patients.

SbstractOxaliplatin was inserted into polymeric matrices aiming to study the interaction of this drug with these polymers and its capability to diffuse to the environment. Tested polymers were: (1) polyethylene glycol (PEG), (2) poly(lactic-co-glycolic acid) (PLGA), and (3) a copolymer of them (PLGA-PEG). The latter two were synthesized by us using polycondensation in bulk. Oxaliplatin was included in the matrices by the melt mixing process followed by casting. Fourier tran sform infrared spectroscopy (FTIR), proton nuclear magnetic resonance ( 1 H-NMR) and X-ray diffraction (DRX) studies of the polymers were performed proving the obtaining of the desired materials. In addition, the interaction between drug and matrices and the release profile of the oxaliplatin from these matrices were analyzed. Among them, PEG did not control the oxaliplatin release. In turn, PLGA and PLGA-PEG present drug release profiles quite similar. Oxaliplatin was completely released from PLGA and PLGA-PEG in 5 hours, by a relaxation mechanism. There was no evidence of oxaliplatin interaction with the different polymers. In addition, as the PEG improves the biocompatibility and biomasking, obtained results prove the obtaining of a drug release system, which allowed the total use of the drug improving the cancer treatment and even the welfare of the patients.

Summary: The antibiotic cotrimoxazole was associated to the multi-block copolymer containing poly(D,L-lactic-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) segments, PLGA-PEG-PLGA, aiming to reach a controlled drug release system. Block copolymer was synthesized via polycondensation of lactic acid and glycolic acid with PEG in situ. In turn, maghemite was synthesized through the co-precipitation method. The drug cotrimoxazole was inserted in the composite through melting mixing method. Several techniques were used to characterize the materials. The materials were characterized by Nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and magnetic force, this last according to the methodology developed by our group. In addition, dissolution profile was studied. These dissolution tests were performed with and without magnetic field, aiming to study the influence of the magnetic field on the dissolution profile. The dissolution was monitored and quantified using the ultraviolet-visible spectrophotometry (UV-Vis), following the USP method for cotrimoxazole tablets. Results demonstrated that nanocomposites presented a good magnetic force, able to keep the magnetic composite trapped in a specific place or tissue. Furthermore, in the presence of a magnetic field, the magnetic nanoparticles were able to perform a magnetic constriction of the material, making the drug release faster than in the absence of the magnetic field. This phenomenon may be useful to perform a fine tuning of the system, allowing the easier adjust of the speed and amount of released drug, useful to improve medical treatments and even the welfare of the patients.

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