Thermal behaviour of malonic acid, sodium malonate and its compounds with some bivalent transition metal ions

Characterization, thermal stability and thermal decomposition of transition metal malonates, MCH(2)C(2)O(4)center dot nH(2)O (M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II)), as well as, the thermal behaviour of malonic acid (C(3)H(4)O(4)) and its sodium Salt (Na(2)CH(2)C(2)O(4)center dot H(2)O) were investigated employing Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC). infrared spectroscopy, TG-FTIR system, elemental analysis and complexometry. The dehydration, as well as, the thermal decomposition of the anhydrous compounds Occurs in a single step. For the sodium malonate the final residue up to 700 C is sodium carbonate, while the transition metal malonates the final residue up to 335 C (Mn), 400 C (Fe), 340 degrees C (Co), 350 C (Ni), 520 C (Cu) and 450 C (Zn) is Mn(3)O(4), Fe(2)O(3), Co(3)O(4). NiO, CuO and ZnO, respectively. The results also provided information concerning the ligand's denticity, thermal behaviour and identification of some gaseous products evolved during the thermal decomposition of these compounds. (C) 2009 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Characterization and Microbiological Application of Ciprofloxacin Loaded in Natural Rubber Latex Membranes

Natural rubber latex (NRL) from Hevea brasiliensis presents interesting characteristics in biomedical research due to its ability to stimulate angiogenesis, cellular adhesion and formation of extracellular matrix. A broad spectrum antibacterial agent used in skin infection is Ciprofloxacin hydrochloride (CIP). It is a fluoroquinolone employed to treat different bacterial infections caused by gram-positive and gram-negative microorganism. The aim of the present study is to promove the CIP incorporation on the natural material due to develop a biomaterial which could accelerate tissue repair and control wounds infection. The biomaterial characterization was made through several technics. The compound presence on the membrane was observed by Scanning Electron Microscopy technique, which shown crystals merged on the material surface. Through X-Ray Powder Diffraction technic was possible to notice the absence of crystallinity (amorphous structure) in the drug-loaded NRL membrane indicating that the drug is molecularly dispersed within the NRL. Besides that, there are no molecular interaction between drug and NRL showed by Fourier Transform Infrared Spectroscopy neither Raman spectroscopy. Additionally, there were no significant changes in the NRL pyrolysis profile when the drug was added, indicating weak interaction between both compounds, as presented by Derivative Thermogravimetric Analysis assay. Comparing the mechanical properties, both samples (with and without CIP) had a similar behavior. Thus, is possible to presume the material preserved enough elasticity to medical application. Furthermore, antimicrobial assay proved that CIP activity was preserved after its incorporation to the NRL. It allows us to conclude that the material has potential application in infected wound treatment