Navegando por Autor "Domingues, Rosana Zacarias"
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Item An efficient and simple procedure to prepare chemically stable and partially carbon-cleaned magnetite from solid-state synthesis for clinical practices in medical oncology.(2020) Andrade, Ângela Leão; Almeida, Katia Júlia de; Freitas, Erico Tadeu Fraga; Mesquita, Aline M.; Pereira, Márcio César; Fabris, José Domingos; Fernandez Outon, Luis Eugenio; Ardisson, José Domingos; Domingues, Rosana ZacariasAs far as medical applications for clinical diagnosis and therapy in oncology are concerned, the use of stables magnetic nanoparticles relies on the magnetocaloric response of their ferrofluid suspensions to an applied alternating current magnetic field. To assure their effectiveness as an advanced material for such a medical technology, some critical properties, as any tendency of the nanoparticles to self-agglomerate and of the mag netic core component to somehow change their chemical nature, must be rigorously inhibited. A sample of chemically stable nanoparticles of magnetite ( Fe3+ 2 Fe2+O2− 4 ) was synthesized through the method consisting of burning a synthetic commercial maghemite (γFe3+ 2 O2− 3 ) with admixed sucrose, to partially reduce Fe3+ → Fe2+. The residual carbon, formed on burning the sucrose, tends to coat the nanoparticles and acts as a protective layer hindering the freshly synthesized hot magnetite from being promptly re-oxidized, on cooling the sample in the open-air atmosphere. As a drawback, this carbon layer tends to be a thermal insulator and must be removed, in order to make the magnetite nanoparticles able to be used as a magnetocaloric material and dissipate heat. A chemically gentle removal of the residual carbon was assayed by treating the sample with H2O2 under stirring or sonication either for 30 min or 60 min. The intrinsic atomic and crystalline structures and other essential properties of this core-shell system were assessed by gas adsorption analysis (BET), powder X-ray diffraction, Fourier-transform infrared spectrometry, Mossbauer ¨ spectroscopy and transmission electron microscopy. Theo retical analyses based on the density functional theory (DFT) were used to interpret the harmonic infrared spectra for the produced magnetite. The efficiency in removing the residual carbon layer formed on the magnetite grain surface was checked by saturation magnetization measurements and CHN elemental analysis. The heat releasing ability of the prepared magnetic sample was evaluated under an AC-induced magnetic field. These results evidenced that the treatment with H2O2 was efficient enough to remove, even though not completely, most of the residual carbon layer, which made the saturation magnetization and the heat released by the treated samples significantly greater than that of the untreated carbon-coated grains. The resulting nano magnetite was found to be a sufficiently clean material for being used for hyperthermia-based procedures, particularly for medical diagnosis and therapy, in oncology.Item Bioactive glass containing 90% SiO2 in hard tissue engineering : an in vitro and in vivo characterization study.(2019) Lehman, Luiz Felipe Cardoso; Noronha, Mariana Saturnino de; Diniz, Ivana Márcia Alves; Silva, Rosangela Maria Ferreira da Costa e; Andrade, Ângela Leão; Lima, Luiz Fernando de Sousa; Alcântara, Carlos Eduardo Pinto de; Domingues, Rosana Zacarias; Ferreira, Anderson José; Silva, Tarcília Aparecida da; Mesquita, Ricardo Alves deBioactive glass has been proved to have many applications in bioengineering due to its bone regenerative properties. In this work, an innovative, highly resorbable bioactive glass containing 90% SiO2 (BG90) to be used as a bone substitute was developed. The BG90 was synthetized by the sol–gel process with the dry step at room temperature. The biomaterial showed in vitro and in vivo bioactivities even with silica content up to 90%. Moreover, the BG90 presented high porosity and surface area due to its homogenously interconnected porous network. In vitro, it was observed to have high cell viability and marked osteoblastic differentiation of rat bone marrow‐derived cells when in contact with BG90 ion extracts. The BG90 transplantation into rat tibia defects was analysed at 1, 2, 3, 4, 7, and 10 weeks post‐operatively and compared with the defects of negative (no graft) and positive (autogenous bone graft) controls. After 4 weeks of grafting, the BG90 was totally resorbed and induced higher bone formation than did the positive control. Bone morphogenetic protein 2 (BMP‐2) expression at the grafting site peaked at 1 week and decreased similarly after 7 weeks for all groups. Only the BG90 group was still exhibiting BMP‐2 expression in the last experimental time. Our data demonstrated that the BG90 could be an attractive candidate to provide useful approaches in hard‐tissue bioengineering.Item Development of a novel nano-biomaterial for biomedical applications.(2018) Machado, Vagner de Oliveira; Andrade, Ângela Leão; Simon, Alice; Fernández, Daniel Ernesto Rodríguez; Fabris, José Domingos; Domingues, Rosana Zacarias; Silva, Raphael Ferreira da; Silva, Thamiris Caroline Esteves; Peixoto, Thainá Lopes; Santos, Cláudio Teodoro dos; Motta, Adriana Cristina; Duek, Eliana Aparecida de Rezende; Silva, Messias Borges; Gomes, Alaelson Vieira; Cabral, Lúcio Mendes; Carmo, Flávia Almada do; Elias, Carlos NelsonThe technological development of biodegradable nanoparticles for drug delivery in medical diagnostics and therapies is addressing increasing efforts to make safer, affordable and more bio-efficient polymeric materials. The preparation via the solvent displacement method of a novel polymeric nanomaterial with new spherical and narrow sizes dispersion is described. It was achieved by choosing the best amount of PLDLA-co-TMC, PEO-PPO-PEO and an adequate acetone:methanol volume ratio, using the factorial design 23 and Box-Behnken experiment design. This new material was loaded with finasteride, the chosen drug model, and its delivery dynamic was determined by the HPLC method. Results revealed that an optimal formulation of PLDLA-co-TMC nanoparticles was found to be composed of 20 mg PLDLA-co-TMC; 37.5 mg PEO-PPO-PEO and a volume acetone:methanol ratio 2.2:0.3. The formulation of this novel biomaterial showed a high encapsulation efficiency of finasteride, controlled release profile along 24 h, without burst effect in the first 4 h, nanometric sizes, spherical shapes, close polydispersity, negative surface charge, unimodal particle size distribution and relatively high thermal stability of the polymer matrix PEO-PPO-PEO/PLDLA-co-TMC. These results support the fabrication of technologically advanced nanoparticles based on high molecular weight PLDLA-co-TMC and their use in the nano-controlled drug release in biomedical applications.Item Equisetum hyemale‑derived unprecedented bioactive composite for hard and soft tissues engineering.(2022) Silva, Rosangela Maria Ferreira da Costa e; Diniz, Ivana Márcia Alves; Gomes, Natália Aparecida; Silva, Guilherme Jorge Brigolini; Ferreira, José Maria da Fonte; Freitas Filho, Rubens Lucas de; Freitas, Erico Tadeu Fraga; Martins, Darliane Aparecida; Domingues, Rosana Zacarias; Andrade, Ângela LeãoAlthough Bioactive Glasses (BGs) have been progressively optimized, their preparation often still involves the use of toxic reagents and high calcination temperatures to remove organic solvents. In the present work, these synthesis related drawbacks were overcome by treating the ashes from the Equisetum hyemale plant in an ethanol/water solution to develop a bioactive composite [glass/ carbon (BG-Carb)]. The BG-Carb was characterized by scanning electron microscopy, and transmission electron microscopy; and its chemical composition was assessed by inductively coupled plasmaoptical emission spectroscopy. Brunauer–Emmett–Teller gas adsorption analysis showed a specifc surface area of 121 m2 g−1. The formation of hydroxyapatite (HA) surface layer in vitro was confrmed by Fourier-transform infrared spectroscopy analysis before and after immersion in simulated body fuid (SBF) solution. The Rietveld refnement of the XRD patterns and selected area electron difraction analyses confrmed HA in the sample even before immersing it in SBF solution. However, stronger evidences of the presence of HA were observed after immersion in SBF solution due to the surface mineralization. The BG-Carb samples showed no cytotoxicity on MC3T3-E1 cells and osteodiferentiation capacity similar to the positive control. Altogether, the BG-Carb material data reveals a promising plant waste-based candidate for hard and soft tissue engineering.Item Glass-ionomer-propolis composites for caries inhibition: flavonoids release, physical-chemical, antibacterial and mechanical properties.(2019) Andrade, Ângela Leão; Lima, Adriana M.; Santos, Vagner Rodrigues; Silva, Rosangela Maria Ferreira da Costa e; Barboza, Ana Paula Moreira; Neves, Bernardo Ruegger Almeida; Vasconcellos, Walison Arthuso; Domingues, Rosana ZacariasThe addition of propolis extract (PE) to the glass ionomer results in an adhesive material for restorative treatment, with interesting properties mainly due to the flavonoids contained in the propolis extract. However, no study of the flavonoid release profile in these materials was reported. This work studies the flavonoid release profile in such materials aiming to contribute to the future synthesis of optimized devices adept to prolong the efficacy of the drug. The study involved the synthesis and study of the physicochemical, antibacterial and mechanical properties of glass ionomer cement (GIC) and glassionomer- propolis composites (GIC-PE). The samples were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analyses. The released concentration of flavonoids, the antimicrobial activity and the compressive strength were also evaluated. Antimicrobial activity was assessed against Streptococcus mutans, Streptococcus salivarius, and Candida albicans, common pathogens in the mouth. The results indicate that the antibacterial activity of GIC-PE samples is closely correlated with the release of flavonoids. The method used to prepare the composite GIC-PE leads to an initial drug delivery burst effect able to diminish partially the population of bacteria tested. The mechanical properties and thermal stability of GIC-PE are higher than those of the GIC and are clearly related to its microstructure. This study is clinically significant because the addition of propolis extract (PE) to the GIC resulted in a novel differentiated product with enhanced mechanical and antimicrobial properties compared to the GIC.Item Magnetically induced heating by iron oxide nanoparticles dispersed in liquids of different viscosities.(2020) Andrade, Ângela Leão; Cavalcante, Luis Carlos Duarte; Fabris, José Domingos; Pereira, Márcio César; Fernandez Outon, Luis Eugenio; Pedersoli, Davyston Carvalho; Ardisson, José Domingos; Domingues, Rosana Zacarias; Ferreira, José Maria da FonteThe AC magnetically induced heating characteristics of uncoated and silica-coated magnetic iron oxide nano particles dispersed in liquids of different viscosities were investigated. The aim was to synthesize and prepare uncoated and silica-coated nanoparticles of maghemite, and evaluate their ability to hyperthermically dissipate heat under an applied AC magnetic field when they are dispersed in liquids of different viscosities. A conceptual approach on the relative contributions of the Néel and the Brownian relaxation mechanisms to the hyperthermic heating of these suspensions is proposed. The microstructure, the physical and chemical properties of the un coated and silica-coated nanoparticles were assessed by transmission electron microscopy; powder X-ray dif fraction; 57Fe Mössbauer spectroscopy; Fourier transform infrared spectroscopy; zeta potential measurements; and conventional chemical analysis. Results of the Rietveld refinement of the XRD patterns and analysis of the collected Mössbauer data are well consistent with maghemite as being the only iron oxide phase. The mean diameters of the uncoated nanoparticles increased from ~6 to 7 nm, to 35 and 78 nm, for added silica coating amounts varying from 1 to 6-fold, respectively. Zeta potential measurements confirmed the efficiency of the nanoparticles sol-gel coating method. When dispersed in low viscosity media (water, triethanolamine, ethylene glycol), uncoated nanoparticles efficiently release heat via both Néel and Brown relaxation mechanisms under an applied oscillating magnetic field, achieving a temperature raise of approximately 21 °C. The silica layers tend to inhibit the Brownian motion of coated particles, making heat dissipation to be preferentially governed by the Néel relaxation of the magnetization vector. This leads to modest rises in temperature of 9 °C when they are dispersed in water or in the PVC (polyvinyl chloride). SAR tests indicate that the maghemite-silica core-shell systems might be useful for advanced technologies in medical practices based on local hyperthermia, particularly in oncology.Item Novel protocol for the solid-state synthesis of magnetite for medical practices.(2015) Paiva, D. L.; Andrade, Ângela Leão; Pereira, Márcio César; Fabris, José Domingos; Domingues, Rosana Zacarias; Alvarenga, Meiry EdivirgesIt is reported a novel approach to prepare nanoparticles of magnetite (Fe3O4) by heating a mixture of synthetic commercial maghemite (γ Fe2O3) with sucrose. This solidstate reaction leads to the chemical reduction of part of the Fe3+ of the precursor oxide to render Fe2+ and Fe3+ in octahedral and Fe3+ in tetrahedral sites of the Fe-O coordination framework. Powder X-ray diffraction patterns, FTIR and 298 K M¨ossbauer spectra confirm the conversion of maghemite into magnetite. Based on these results, the optimal sucrose:maghemite rate was found to be 4.Item Ph effect on the synthesis of magnetite nanoparticles by the chemical reduction-precipitation method.(2010) Andrade, Ângela Leão; Souza, Diana Manzi de; Pereira, Márcio César; Fabris, José Domingos; Domingues, Rosana ZacariasThis work aimed at putting in evidence the influence of the pH on the chemical nature and properties of the synthesized magnetic nanocomposites. Saturation magnetization measurements evidenced a marked difference of the magnetic behavior of samples, depending on the final pH of the solution after reaction. Magnetite and maghemite in different proportions were the main magnetic iron oxides actually identified. Synthesis with final pH between 9.7-10.6 produced nearly pure magnetite with little or no other associated iron oxide. Under other synthetic conditions, goethite also appears in proportions that depended upon the pH of the synthesis medium.Item Preparation and characterization of Fe3O4-Pt nanoparticles.(2017) Andrade, Ângela Leão; Cavalcante, Luis Carlos Duarte; Fabris, José Domingos; Pereira, Márcio César; Ardisson, José Domingos; Domingues, Rosana ZacariasPt and Pt-based nanomaterials are active anticancer drugs for their ability to inhibit the division of living cells. Nanoparticles of magnetite containing variable proportions of platinum were prepared in the laboratory. The magnetite nanoparticles with platinum (Pt-Fe3O4) were obtained by reducing the Fe3+ of the maghemite (γ Fe2O3) mixed with platinum (II) acetylacetonate and sucrose in two inversely coupled ceramic crucibles and heated in a furnace at 400 ◦C for 20 min. The formed carbon during this preparation acts to chemically reduce the ferric iron in maghemite. Moreover, its residual layer on the particle surface prevents the forming magnetite from oxidizing in air and helps retain the platinum in the solid mixture. The produced Pt-magnetite samples were characterized by 57Fe-M¨ossbauer spectroscopy, powder X-ray diffraction, scanning electron microscopy, and magnetization measurements.Measurements of AC magnetic-field-induced heating properties of the obtained nanocomposites, in aqueous solution, showed that they are suitable as a hyperthermia agent for biological applications.Item Preparation of composite with silica-coated nanoparticles of iron oxide spinels for applications based on magnetically induced hyperthermia.(2013) Andrade, Ângela Leão; Fabris, José Domingos; Pereira, Márcio César; Domingues, Rosana Zacarias; Ardisson, José DomingosIt is reported a novel method to prepare magnetic core (iron oxide spinels)–shell (silica) composites containing well-dispersed magnetic nanoparticles in aqueous solution. The synthetic process consists of two steps. In a first step, iron oxide nanoparticles obtained through co-precipitation are dispersed in an aqueous solution containing tetramethylammonium hydroxide; in a second step, particles of this sample are coated with silica, through hydrolyzation of tetraethyl orthosilicate. The intrinsic atomic structure and essential properties of the core–shell system were assessed with powder X-ray diffraction, Fourier transform infrared spectrometry, Mössbauer spectroscopy and transmission electron microscopy. The heat released by this ferrofluid under an AC-generated magnetic field was evaluated by following the temperature evolution under increasingmagnetic field strengths.Results strongly indicate that this ferrofluid based on silica-coated iron oxide spinels is technologically a very promising material to be used in medical practices, in oncology.Item Preparation of hybrid nanocomposite particles for medical practices.(2021) Machado, Vagner de Oliveira; Andrade, Ângela Leão; Fabris, José Domingos; Freitas, Erico Tadeu Fraga; Ferreira, José Maria da Fonte; Simon, Alice; Domingues, Rosana Zacarias; Fernandez Outon, Luis Eugenio; Carmo, Flávia Almada do; Souza, Antônio Carlos dos Santos; Cardoso, Hugo Saba PereiraThis study addresses the preparation of hybrid nanoparticles comprised of magnetite (Fe3O4) cores and a surface functionalized with tetramethylammonium hydroxide (TMAOH). The stabilized core nanoparticles were subse quently coated with a polymer matrix consisting of poly(L-co-D,L lactic acid-co-trimethylene carbonate) and poly (ethylene oxide) − poly(propylene oxide) − poly(ethylene oxide) triblock copolymer. The novel core/shell hybrid nanoparticles combine the concepts of electromagnetic heating by the magnetite cores with the drug storage and release ability of the polymeric shell. These multifunctional hybrid nanoparticles are intended for hyperthermia clinical protocols in local drug delivery and medical practices in oncology. The essential physical features of these hybrid composite nanoparticles were assessed using an array of appropriate advanced char acterization techniques. The equivalent average diameters of the composite nanoparticles were relatively uni form and their core/shell mass ratio was estimated through thermogravimetric analysis. The weakening of the intermolecular interactions with decreasing thickness of the coating led to a concomitant decrease in the melting temperature of the shell. The polydispersity index data from dynamic light scattering analysis enabled the conclusion that polymeric species contained in 10 mL of the polymeric matrix solution could effectively coat a maximum of core particles contained in 0.5 mL of ferrofluid.Item Preparation of magnetoliposomes with a green, low-cost, fast and scalable methodology and activity study against S. aureus and C. freundii bacterial strains.(2018) Silva, Rosangela Maria Ferreira da Costa e; Lara, Luciano Roni Silva; López Aguilar, Jorge Luis; Andrade, Ângela Leão; Oliveira, Junnia A. C.; Takahashi, Jacqueline Aparecida; Vieira, Henriete da Silva; Matencio, Tulio; Stumpf, Humberto Osório; Domingues, Rosana ZacariasA novel, fast, low-cost and scalable methodology to prepare stable magnetoliposomes (MGLs), without the use of organic solvents, is described. The concept of the work is based on the dual use of soy lecithin associated to a new liposome preparation methodology. Soy lecithin was used to coat the nanoparticles of magnetite (Fe3 O4 @lecithin) and for encapsulation of Fe3 O4 @lecithin (Lip-Fe3 O4 @lecithin). Liposomes with size less than 160 nm, polydispersity index of 0.25 and zeta potential of -41 mV, were prepared with the use of autoclave and sonication. The liposomal formulations containing magnetite and stigmasterol (Lip-Fe3 O4 @lecithin, Lip-Stigma and Lip-Stigma-Fe3 O4 @lecithin) were shown to be promising for the application as antibacterial. The liposomal formulation and magnetite were characterized by the following techniques: conventional and high-resolution transmission electron microscopy (TEM/HRTEM), energy-filtered transmission electron microscopy (EFTEM), proton nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), dynamic light scattering (DLS) and zeta potential. The Lip-Fe3 O4 @lecithin had a minimum inhibitory concentration (MIC) of 8.4 µg mL-1 in the presence of 200 Oe magnetic field against S. aureus.Item Síntese, caracterização físico-química e avaliação da hematocompatibilidade, in vitro, de nanopartículas de magnetita.(2022) Gomes, Aline Alexandrina; Andrade, Ângela Leão; Valverde, Thalita Marcolan; Domingues, Rosana Zacarias; Andrade, Ângela Leão; Rocha, Diego Gomes; Silva, Rosangela Maria Ferreira da Costa ePesquisas em nanobiotecnologia têm evoluído nos últimos anos. Na área médica, por exemplo, nanopartículas magnéticas têm sido estudadas como agentes de contraste, bioensaios magnéticos, e como carreadoras de fármacos associados à terapia de hipertermia. Sínteses de nanopartículas magnéticas estão sendo feitas com objetivo de obter materiais superparamagnéticos, com formas uniformes, no caso esféricas, potencial magnético e de aquecimento satisfatórios sob campo magnético oscilante, externamente aplicado, e capacidade de adsorver fármacos na sua estrutura para serem usadas como material de transporte para células tumorais. Essas caraterísticas fazem com que essas nanopartículas magnéticas possam ser classificadas como materiais multimodais. Estudos de hipertermia com nanopartículas magnéticas podem ser usados de forma auxiliar aos tratamentos convencionais (quimioterapia e radioterapia). A finalidade do uso da hipertermia, é diminuir os efeitos colaterais dessas terapias convencionais, já que, a hipertermia consiste em um aumento da temperatura local que pode enfraquecer ou matar as células doentes além de promover a liberação de fármacos diretamente para áreas doentes, potencializando o tratamento. A sensibilidade de células tumorais frente ao tratamento por hipertermia pode ser explicada pelo fato que o tecido tumoral apresenta alterações importantes no microambiente tecidual que prejudica a dissipação do calor. Para que um material possa ser administrado em um organismo vivo, como os materiais usados em hipertermia, é importante avaliar previamente a sua biocompatibilidade por meio de ensaios de biologia celular. Sendo assim, o objetivo desse trabalho foi sintetizar, funcionalizar e revestir nanopartículas magnéticas com polímeros orgânicos a fim de estabilizá-las em soluções aquosas antes do seu uso. Uma análise multivariada foi feita para a obtenção das condições que produzem os menores tamanhos de nanopartículas. A validação do modelo matemático, obtido nessa análise, foi feito pela análise de variância (ANOVA). Caracterizações físico – químicas das partículas sintetizadas e revestidas foram feitas por TEM; HRTEM; Hipertermia; FTIR; DLS; PdI e Potencial Zeta. Adicionalmente, foi realizada uma avaliação biológica por meio do ensaio de hematocompatibilidade in vitro.Item A tetravalent dengue nanoparticle stimulates antibody production in mice.(2012) Silva, Elisângela F.; Orsi, Mariana; Andrade, Ângela Leão; Domingues, Rosana Zacarias; Silva, Breno de Mello; Araújo, Helena Rocha Corrêa de; Pimenta, Paulo Filemon Paolucci; Diamond, Michael S.; Rocha, Eliseu S. O.; Kroon, Erna Geessien; Malaquias, Luiz Cosme Cotta; Coelho, Luiz Felipe LeomilDengue is a major public health problem worldwide, especially in the tropical and subtropical regions of the world. Infection with a single Dengue virus (DENV) serotype causes a mild, self-limiting febrile illness called dengue fever. However, a subset of patients experiencing secondary infection with a different serotype progresses to the severe form of the disease, dengue hemorrhagic fever/dengue shock syndrome. Currently, there are no licensed vaccines or antiviral drugs to prevent or treat dengue infections. Biodegradable nanoparticles coated with proteins represent a promising method for in vivo delivery of vaccines.Item Theoretical and experimental studies of the controlled release of tetracycline incorporated into bioactive glasses.(2018) Andrade, Ângela Leão; Militani, Isabela Aparecida; Almeida, Katia Júlia de; Belchior, Jadson Cláudio; Reis, Sérgio C. dos; Silva, Rosangela Maria Ferreira da Costa e; Domingues, Rosana ZacariasSeveral authors have studied the release profile of drugs incorporated in different devices. However, to the best of our knowledge, although many studies have been done on the release of tetracycline, in these release devices, no study has investigated if the released compound is actually the tetracycline, or, instead, a degraded product. This approach is exploited here. In this work, we analyse the influence of two drying methods on the tetracycline delivery behaviour of synthesised glasses using the sol-gel process. We compare the drying methods results using both theoretical models and practical essays, and analyse the chemical characteristic of the released product in order to verify if it remains tetracycline. Samples were freeze-dried or dried in an oven at 37°C and characterised by several methods such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TG), differential thermogravimetric analysis (DTG), differential thermal analyses (DTA) and gas adsorption analysis (BET). The released concentration of tetracycline hydrochloride was studied as a function of time, and it was measured by ultraviolet spectrophotometry in the tetracycline wavelength. The drug delivery profiles were reasonably consistent with a diffusion model analysis. In addition, we observed higher release rates for the freeze-dried compared to those dried in an oven at 37°C. This higher release can be attributed to larger pore size for the freeze-dried sample systems with tetracycline, which promoted more water penetration, improving the drug diffusion. The analysis of the solution obtained in the release tests using high-performance liquid chromatography- mass spectrometry (HPLC-MS) confirmed that tetracycline was being released.