RESUMO
Periodontal pain is a public health problem derived from different conditions, including periodontal diseases, prosthetic complications, and even extractions performed by dentist. There are various treatments to control acute dental pain, being the administration of analgesics, such as Lysine Clonixinate (LC), a common practice. Unfortunately, higher and repeated dosages are usually required. The purpose of this work was to develop a prolonged release pharmaceutical form as an alternative treatment for dental pain. Hence, we conceived a film based on guar gum and loaded different concentrations of LC. We evaluated the film's appearance, brittleness, strength, and flexibility, and then chose one formulation for adequate characteristics. Subsequently, we assessed the morphology, thermal behavior, and swelling properties of the films (LC-free and -loaded). Finally, we performed the release studies of LC from the films in vitro using a simulated saliva medium and employed several mathematical models to evaluate the release kinetics. Guar gum is a natural polymer obtained from the endosperm of Cyamopsis tetragonolobus that presents properties such as biosafety, biocompatibility, and biodegradability. Thus, it represents a potential excipient for use in pharmaceutical formulations. Moreover, our results revealed that the LC-loaded film presented a high adherence, suitable swelling behavior, high LC content, and a prolonged drug release. Therefore, the LC-loaded film may be considered a potential option to be applied as an alternative to treat dental pain.
Assuntos
Clonixina/análogos & derivados , Lisina/análogos & derivados , Dor/tratamento farmacológico , Doenças Periodontais/tratamento farmacológico , Polissacarídeos Bacterianos/química , Analgésicos/farmacocinética , Analgésicos/uso terapêutico , Clonixina/farmacocinética , Clonixina/uso terapêutico , Liberação Controlada de Fármacos , Excipientes/química , Humanos , Cinética , Lisina/farmacocinética , Lisina/uso terapêutico , Membranas Artificiais , Microscopia Eletrônica de Varredura , Dor/complicações , Doenças Periodontais/complicações , Polímeros/química , Polissacarídeos Bacterianos/ultraestrutura , Temperatura , Termogravimetria/métodosRESUMO
Bacterial vaginosis is a vaginal infection that affects 60% of women of reproductive age worldwide. It is mainly caused by the bacterium Gardnerella vaginalis and is a factor that increases the probability of getting sexually transmitted diseases. We aimed to develop a new pharmaceutical form for the treatment of vaginal infections. We employed the solving-casting method to fabricate a polymeric film with Xanthan gum, a natural polymer produced by the bacterium Xanthomonas campestris, and metronidazole, one of the most commonly used drugs for vaginal infections. In order to characterize the film, we measured pH, dose uniformity, dissolution profile, and the percentage of swelling. Moreover, we performed a thermogravimetric analysis and scanning electron microscopy. The results demonstrated a pH suitable for vaginal application and uniform distribution of the drug in the film. Also, the formulation exhibited a high percentage of swelling and a slow release of the drug in a simulated vaginal fluid medium. All these attributes indicated that the manufactured film has ideal characteristics to be used and administered vaginally. It could be an excellent alternative to treat bacterial vaginosis and also improve user adherence.
Assuntos
Gardnerella vaginalis/efeitos dos fármacos , Metronidazol/uso terapêutico , Polissacarídeos Bacterianos/química , Vagina/efeitos dos fármacos , Vaginose Bacteriana/tratamento farmacológico , Antibacterianos/administração & dosagem , Antibacterianos/farmacocinética , Antibacterianos/uso terapêutico , Liberação Controlada de Fármacos , Feminino , Gardnerella vaginalis/fisiologia , Humanos , Concentração de Íons de Hidrogênio , Membranas Artificiais , Metronidazol/administração & dosagem , Metronidazol/farmacocinética , Microscopia Eletrônica de Varredura , Polímeros/química , Polissacarídeos Bacterianos/ultraestrutura , Temperatura , Termogravimetria/métodos , Resultado do Tratamento , Vagina/microbiologia , Vaginose Bacteriana/microbiologiaRESUMO
Bacterial cellulose (BC) is a natural polymer that has fascinating attributes, such as biocompatibility, low cost, and ease of processing, being considered a very interesting biomaterial due to its options for moldability and combination. Thus, BC-based compounds (for example, BC/collagen, BC/gelatin, BC/fibroin, BC/chitosan, etc.) have improved properties and/or functionality, allowing for various biomedical applications, such as artificial blood vessels and microvessels, artificial skin, and wounds dressing among others. Despite the wide applicability in biomedicine and tissue engineering, there is a lack of updated scientific reports on applications related to dentistry, since BC has great potential for this. It has been used mainly in the regeneration of periodontal tissue, surgical dressings, intraoral wounds, and also in the regeneration of pulp tissue. This review describes the properties and advantages of some BC studies focused on dental and oral applications, including the design of implants, scaffolds, and wound-dressing materials, as well as carriers for drug delivery in dentistry. Aligned to the current trends and biotechnology evolutions, BC-based nanocomposites offer a great field to be explored and other novel features can be expected in relation to oral and bone tissue repair in the near future.
Assuntos
Bactérias/química , Materiais Biocompatíveis/química , Celulose/química , Odontologia , Celulose/ultraestrutura , Odontologia/métodos , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/ultraestruturaRESUMO
Broadband dielectric spectroscopy was used to investigate the molecular α-relaxation of the exopolysaccharides (EPS) extracted from Nostoc commune cyanobacteria. The EPS were modified in different ways. EPS were carboxymethylated to obtain carboxymethyl-exopolysaccharides (CEPS). EPS and CEPS were doped with ammonium iodide and 1-butyl-3-methylimidazolium chloride. An α relaxation process was observed for all specimens. The temperature dependence of the relaxation times for pure and doped, EPS and CEPS polymers exhibited non-Arrhenius behavior. This relaxation process was associated with the glass transition of the complex heteropolysaccharides produced by the cyanobacteria. The molecular mobility at the glass transition, Tg, was affected by both the carboxymethylation treatment and the doping. The fragility index also decreased for the doped specimens, which may be attributed to an increase in the mobility of the polymer chains due to the plasticizing effect of the doping agents.
Assuntos
Nostoc commune/química , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/isolamento & purificação , Fracionamento Químico , Monossacarídeos/química , Polissacarídeos Bacterianos/ultraestrutura , Análise Espectral , TemperaturaRESUMO
Bacterial cellulose (BC) nanoribbons were partially acetylated by a simple direct solvent-free route catalyzed by citric acid. The assay of reaction conditions within chosen intervals (i.e. esterification time (0.5-7h), catalyst content (0.08-1.01mmol/mmol AGU), and temperature (90-140°C)), illustrated the flexibility of the methodology proposed, with reaction variables which can be conveniently manipulated to acetylate BC to the required degree of substitution (DS) within the 0.20-0.73 interval. Within this DS interval, characterization results indicated a surface-only process in which acetylated bacterial cellulose with tunable DS, preserved fibrous structure and increased hydrophobicity could be easily obtained. The feasibility of reusing the catalyst/excess acylant in view of potential scale-up was also illustrated.
Assuntos
Celulose/análogos & derivados , Ácido Cítrico/química , Gluconacetobacter xylinus/química , Polissacarídeos Bacterianos/análogos & derivados , Acetilação , Catálise , Celulose/ultraestrutura , Esterificação , Polissacarídeos Bacterianos/ultraestruturaRESUMO
An electrically conducting composite based on bacterial cellulose (BC) and polypyrrole (PPy) was prepared through in situ oxidative polymerization of pyrrole (Py) in the presence of BC membrane using ammonium persulfate (APS), as an oxidant. The electrical conductivity, morphology, mechanical properties and thermal stability of the composites obtained using APS (BC/PPy·APS) were evaluated and compared with BC/PPy composites prepared using as oxidant agent Iron III chloride hexahydrate (FeCl3·6H2O). The morphology of the BC/PPy·APS composites is characterized by spherical conducting nanoparticles uniformly distributed on the BC nanofiber surface, while the composites produced with FeCl3·6H2O (BC/PPy·FeCl3) is composed of a continuous conducting polymer layer coating the BC-nanofibers. The electrical conductivity of BC/PPy·FeCl3 was 100-fold higher than that found for BC/PPy·APS composites. In order to understand the site-specific interaction between PPy and BC functional groups, both composites were characterized by Fourier transform infrared (attenuated total reflectance mode) spectroscopy attenuation reflectance (FTIR-ATR) and X-ray photoelectron spectrometry (XPS). The affinity between functional groups of PPy·FeCl3 and BC is higher than that found for BC/PPy·APS composite. In addition, the tensile properties were also influenced by the chemical affinity of both components in the polymer composites.
Assuntos
Celulose/química , Nanocompostos/química , Polímeros/química , Polissacarídeos Bacterianos/química , Pirróis/química , Celulose/ultraestrutura , Condutividade Elétrica , Nanocompostos/ultraestrutura , Oxirredução , Espectroscopia Fotoeletrônica , Polimerização , Polissacarídeos Bacterianos/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à Tração , Termodinâmica , TermogravimetriaRESUMO
The Acidithiobacillus ferrooxidans response to stress associated with the drying process is known to be the production of extracellular polymeric substance (EPS) coverage. Here, samples of A. ferrooxidans suspensions grown in 1.8 pH and 3.0 pH and dried on mica and silicon are shown to form a structure of isolated bacteria. Individual bacteria coverage patterns were imaged by atomic force microscopy (AFM) on hydrophobic (silicon) and hydrophilic (mica) substrates. A comparison of images of covered and uncovered bacteria establish the volume of individual EPS coverage. The EPS production for bacteria on hydrophobic substrates shows a substantial decrease (a factor of 30) in the EPS volume per bacterium when compared with the one on hydrophilic substrates. Shape and volume determination of EPS structures on bacteria as a function of hydrophobicity or hydrophilicity of the substrate may help to determine the functions of EPS on bacterial aggregates.
Assuntos
Acidithiobacillus/ultraestrutura , Microscopia de Força Atômica , Polissacarídeos Bacterianos/análise , Polissacarídeos Bacterianos/ultraestrutura , Acidithiobacillus/crescimento & desenvolvimento , Acidithiobacillus/metabolismo , Silicatos de Alumínio , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , SilícioRESUMO
Extracellular polysaccharides play an important role in aggregation and surface colonization of plant-associated bacteria. In this work, we report the time course production and monomer composition of the exopolysaccharide (EPS) produced by wild type strain and several mutants of the plant growth promoting rhizobacterium (PGPR) Azospirillum brasilense. In a fructose synthetic medium, wild type strain Sp7 produced a glucose-rich EPS during exponential phase growth and an arabinose-rich EPS during stationary and death phase growth. D-glucose or L-arabinose did not support cell growth as sole carbon sources. However, glucose and arabinose-rich EPSs, when used as carbon source, supported bacterial growth. Cell aggregation of Sp7 correlated with the synthesis of arabinose-rich EPS. exoB (UDP-glucose 4'-epimerase), exoC (phosphomannomutase) and phbC (poly-beta-hydroxyburyrate synthase) mutant strains, under tested conditions, produced arabinose-rich EPS and exhibited highly cell aggregation capability. A mutant defective in LPS production (dTDP 4-rhamnose reductase; rmlD) produced glucose-rich EPS and did not aggregate. These results support that arabinose content of EPS plays an important role in cell aggregation. Cell aggregation appears to be a time course phenomenon that takes place during reduced metabolic cell activity. Thus, aggregation could constitute a protected model of growth that allows survival in a hostile environment. The occurrence of exoC and rmlD was detected in several species of Azospirillum.