MARIA JOSE ALVES DE OLIVEIRA

MARIA JOSE ALVES DE OLIVEIRA

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Effect of gamma radiation cobalt-60 on caffeine
2019 - MAIA, TIAGO C. dos S.; LUGAO, ADEMAR B.; AZOUBEL, ROBERTA; RAPOSO, MARCOS T.; OLIVEIRA, MARIA J.A. de
Objective: The objective of the study was to evaluate the effects of the incidence of gamma radiation of Cobalt-60 on caffeine. Material and Methods: The samples were studied in aqueous solution and powdered form after irradiation at doses: 2, 4, 8, 16 and 32 kGy by ionizing radiation source of 60Co. After wards, they were analyzed by differential scanning calorimetry (DSC), thermogravimetry (TG), and high performance liquid chromatography (HPLC). Results and Discussion: For the DSC technique no changes were observed in the curves after irradiation, which could witness changes in physicochemical properties after irradiation. The TG corroborated with the expected mass loss of caffeine, independent of the action of ionizing radiation. Furthermore, the results obtained by the chromatographic analysis did not show a percentage of caffeine degradation in the dose of the applied radiation when compared to the nonirradiated caffeine. Conclusion: In view of the results obtained, it was possible to observe the stability of caffeine on the influence of gamma radiation on the Cobalt-60 source.
Effect of gamma radiation on polyvinylpyrrolidone hydrogels
2017 - OLIVEIRA, M.J.A.; VASQUEZ, P.A.S.; ALCANTARA, M.T.S.; MUNHOZ, M.M.L.; LUGAO, A.B.
Polyvinylpyrrolidone (PVP) hydrogels have been investigated as drug delivery matrices for the treatment of wounds, such as cutaneous leishmaniasis, and matrices with silver nanoparticles for chronic wounds and burns. The preparation of such hydrogels can occur by various cross-linking methods, such as gamma, chemical, physical, among others. The most feasible for wound dressings is gamma irradiation from cobalt-60, because gamma irradiation simultaneously promotes crosslinking and sterilization, leaving the wound dressing ready for use. The objective of this work was to investigate the effect on physico- chemical properties of gamma radiation on PVP hydrogel according to the radiation absorbed dose variation. The PVP hydrogels were irradiated with doses of 5, 15, 25, 35, 45, 55, 65, 75 and 95kGy at dose rate of 5 kGy/h and characterized by swelling, thermogravimetric and mechanical analysis. Results shown a favorable dose range window for processing of these hydrogels related to the application. The results showed that mechanical strength was affected at doses starting at 25 kGy.
Synthesis and characterization of polymeric hydrogel containing caffeine for cosmeceutical applications
2017 - SANTOS, TIAGO C.; OLIVEIRA, MARIA J.A.; LUGAO, ADEMAR B.
Caffeine, a substance with belongs to the group of methylxanthines, is alkaloids that penetrate in the human epidermis but is not easily absorbed into the bloodstream. With a dermatological active substance, it exerts action on the subcutaneous adipose tissue causing adipocyte lipolysis through the inhibition of phosphodiesterase. Based on these considerations, the objective of this study was to investigate the behavior of caffeine in a polymeric hydrogel matrix, for possible cosmeceutical applications. The hydrogels were cross-linked and sterilized by colbat-60 source gamma irradiation. In the characterization, were used thermogravimetry (TGA), scanning electron microscopy (SEM), differential scanning calorimetry (DSC). It was possible to observe by SEM the presence of crystals in the hydrogel sample. The DSC experiment confirmed a crystallinity of the sample and that caffeine is not degraded by gamma irradiation at 25 kGy. The results were satisfactory, allowing a new investigations that certify the benefits of its application.
Membranes of hidrogels of PVAI/clay by gamma radiation
2010 - OLIVEIRA, M.J.A. de; PARRA, D.F.; AMATO, V.S.; LUGAO, A.B.
Modificacoes no comportamento de hidrogel de PVAL com a presenca de argila
2010 - OLIVEIRA, M.J.A.; PARRA, D.F.; AMATO, V.S.; LUGAO, A.B.
O Poly(N-2-vinylpirrolidone) (PVP) Poly(vinylalcohol)(PVAl)/Laponite RD Hydrogels Nanocomposite Membranes
2012 - OLIVEIRA, M.J.A.; PARRA, D.F.; LUGAO, ADEMAR B.
Hybrid hydrogels produced by ionizing radiation technique for drug delivery
2011 - OLIVEIRA, MARIA J.A.; PARRA, DUCLERC F.; AMATO, VALDIR S.; LUGAO, ADEMAR B.
Poly(N-2-vinylpirrolidone)(PVP)Poly(vinylalcohol)(PVAl)/Laponite RD hydrogels nanocomposite membranes
2011 - OLIVEIRA, M.J.A.; PARRA, D.F.; AMATO, V.S.; LUGAO, A.B.
Glucantime drug delivery comparison between crosslinked membranes irradiation versus esterification
2009 - OLIVEIRA, MARIA J.A.; AMATO, VALDIR S.; PARRA, DUCLERC F.; LUGAO, ADEMAR B.
Characterization and improvement of PVAl/PVP/PEG hydrogels
2009 - OLIVEIRA, MARIA J.A.; PARRA, DUCLERC F.; ALMEIDA, MONISE F.; LUGAO, ADEMAR B.