Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Spectrochim Acta A Mol Biomol Spectrosc ; 316: 124289, 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-38692101

RESUMO

Biphasic calcium phosphate (BCP), consisting of bioceramics such as HAp + ß-TCP and Ca10(PO4)6(OH)2 + Ca3(PO4)2, is a popular choice for optimizing performance due to its superior biological reabsorption and osseointegration. In this study, BCP was produced by calcining the bones of tilapia fish (Oreochromis niloticus) reared in net cages and slaughtered at an age ranging from 15 to 420 days. The bones were cleaned and dried, calcined at 900 °C for 8 h, and then subjected to high-energy grinding for 3 h to produce BCP powders. After the calcination process, the crystalline phase's hydroxyapatite (HAp) and/or beta-tricalcium phosphate (ß-TCP) were present in the composition of the bioceramic. The age-dependent variation in phase composition was confirmed by complementary vibrational spectroscopy techniques, revealing characteristic peaks and bands of the bioceramic. This variation was marked by an increase in HAp phase and a decrease in ß-TCP phase. Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) from 25 to 1400 °C showed the characteristic mass losses of the material, with a greater loss observed for younger fish, indicating the complete removal of organic components at temperatures above 600 °C. Comparison of the results obtained by X-Ray Diffraction (XRD) and Rietveld refinement with Raman spectroscopy showed excellent agreement. These results showed that with temperature and environment control and adequate fish feeding, it is possible to achieve the desired amounts of each phase by choosing the ideal age of the fish. This bioceramic enables precise measurement of HAp and ß-TCP concentrations and Ca/P molar ratio, suitable for medical orthopedics and dentistry.


Assuntos
Osso e Ossos , Cerâmica , Análise Espectral Raman , Animais , Cerâmica/química , Osso e Ossos/química , Tilápia/metabolismo , Difração de Raios X , Hidroxiapatitas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Fosfatos de Cálcio/química , Termogravimetria
2.
AAPS PharmSciTech ; 18(8): 2854-2861, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28411332

RESUMO

Polymers are essential tools in the research and development of new therapeutic devices. The diversity and flexibility of these materials have generated high expectations in the composition of new materials with extraordinary abilities, especially in the design of new systems for the modified release of pharmaceutically active ingredients. The natural polymer rosin features moisture protection and pH-dependent behavior (i.e., it is sensitive to pH > 7.0), suggesting its possible use in pharmaceutical systems. The synthetic polymer Eudragit® RS PO is a low-permeability material, the disintegration of which depends on the time of residence in the gastrointestinal tract. The present study developed a polymeric material with desirable physicochemical characteristics and synergistic effects that resulted from the inherent properties of the associated polymers. Isolated films were obtained by solvent evaporation and subjected to a water vapor transmission test, scanning electron microscopy, calorimetry, Fourier transform-infrared (FT-IR) spectroscopy, micro-Raman spectroscopy, and mechanical analysis. The new polymeric material was macroscopically continuous and homogeneous, was appropriately flexible, had low water permeability, was vulnerable in alkaline environments, and was thermally stable, maintaining an unchanged structure up to temperatures of ∼400°C. The new material also presented potentially suitable characteristics for application in film coatings for oral solids, suggesting that it is capable of carrying therapeutic substances to distal regions of the gastrointestinal tract. These findings indicate that this new material may be added to the list of functional excipients.


Assuntos
Materiais Revestidos Biocompatíveis/química , Ácidos Polimetacrílicos/química , Resinas Vegetais/química , Materiais Revestidos Biocompatíveis/análise , Avaliação Pré-Clínica de Medicamentos/métodos , Excipientes/análise , Excipientes/química , Microscopia Eletrônica de Varredura/métodos , Permeabilidade , Polímeros/análise , Polímeros/química , Ácidos Polimetacrílicos/análise , Resinas Vegetais/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...