RESUMEN
In an effort to preserve traditional medicine knowledge and to uncover information about disease patterns and treatment in the Lao People's Democratic Republic (PDR), linguistic experts have scanned centuries-old medical palm leaf manuscripts for disease entries. A list of more than 7000 diseases has resulted, shedding valuable light onto the medical history and traditional medicine heritage of the people of Laos, as well as providing an index for faster research into specific diseases and their traditional treatments.
RESUMEN
1-Hydroxybisphosphonate derivatives of ciprofloxacin, gatifloxacin and moxifloxacin have been synthesized using Cu(I) catalyzed azide-alkyne 1,3-dipolar cycloaddition reaction. The 1,2,3-triazol linked hydroxybisphosphonate derivative of ciprofloxacin exhibited antibacterial activity comparable to the parent antibiotic and all fluoroquinolone-bisphosphonates displayed osteotropic properties in a bone model.
Asunto(s)
Antibacterianos/síntesis química , Antibacterianos/farmacología , Fluoroquinolonas/síntesis química , Fluoroquinolonas/farmacología , Organofosfonatos/química , Adsorción , Antibacterianos/química , Antibacterianos/metabolismo , Bacterias/efectos de los fármacos , Huesos/efectos de los fármacos , Huesos/metabolismo , Durapatita/química , Durapatita/metabolismo , Fluoroquinolonas/química , Fluoroquinolonas/metabolismo , NanoestructurasRESUMEN
The present investigation describes the preparation and characterization of novel biodegradable nanoparticles based on complexation of poly-gamma-glutamic acid (gamma-PGA) with bivalent lead ion. The prepared nano-systems were stable in aqueous media at low pH, neutral and mild alkaline conditions. The particle size and the size of the complexes were identified by dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. It was found that the size of the complexes depended on the pH and concentrations of gamma-PGA and lead ions. Particle sizes measured by TEM revealed that at low concentrations, nanosized particles were formed, however, at high concentrations of gamma-PGA and lead ions, the formation of large aggregates with a broad size distribution was promoted. The size of individual particles was in the range of 40-100 nm measured by TEM. The results from the DLS measurements showed that the low and high pH values in mixtures with high concentrations of gamma-PGA and Pb2+ ions favored the growth of large complexes. The gamma-PGA nanoparticles, composed of a biodegradable biomaterial with high flocculating and heavy metal binding activity, may be useful for various water treatment applications.
Asunto(s)
Plomo/química , Nanopartículas/química , Ácido Poliglutámico/análogos & derivados , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Floculación , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Transmisión , Nanopartículas/ultraestructura , Nefelometría y Turbidimetría , Tamaño de la Partícula , Ácido Poliglutámico/químicaRESUMEN
The present investigation describes the synthesis and characterization of novel biodegradable nanoparticles based on chitosan. Poly(ethylene glycol) dicarboxylic acid was used for intramolecular cross-linking of the chitosan linear chains. The condensation reaction of carboxylic groups and pendant amino groups of chitosan was performed by using water-soluble carbodiimide. The prepared nanosystems were stable in aqueous media. The structure of the products was determined by nuclear magnetic resonance (NMR) spectroscopy, and the particle size was identified by dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. It was found that biodegradable cross-linked chitosan nanoparticles experienced considerable swelling because of the length and flexibility of the cross-linking agent. The aqueous solutions or dispersions of nanoparticles were stable and clear or mildly opalescent systems depending on the ratio of cross-linking and molecular weight of chitosan, findings consistent with values of transmittance above 75%. Particle size measured by TEM varied in the range of 4-24 nm. In the swollen state, the average size of the individual particles measured by DLS was in the range of 50-120 nm depending on the molecular weight of chitosan and the ratio of cross-linking.
Asunto(s)
Quitosano/química , Nanopartículas , Polietilenglicoles/química , Espectroscopía de Resonancia Magnética , Microscopía Electrónica de Transmisión , Peso Molecular , Tamaño de la Partícula , SolubilidadRESUMEN
The present investigation describes the synthesis and characterization of novel biodegradable nanoparticles based on chitosan for biomedical applications. Natural di- and tricarboxylic acids were used for intramolecular cross-linking of the chitosan linear chains. The condensation reaction of carboxylic groups and pendant amino groups of chitosan was performed by using water-soluble carbodiimide. This method allows the formation of polycations, polyanions, and polyampholyte nanoparticles. The prepared nanosystems were stable in aqueous media at low pH, neutral, and mild alkaline conditions. The structure of products was determined by NMR spectroscopy, and the particle size was identified by laser light scattering (DLS) and transmission electron microscopy (TEM) measurements. It was found that particle size depends on the pH, but at a given pH, it was independent of the ratio of cross-linking and the cross-linking agent. Particle size measured by TEM varied in the range 60-280 nm. In the swollen state, the average size of the particles measured by DLS was in the range 270-370 nm depending on the pH. The biodegradable cross-linked chitosan nanoparticles, as solutions or dispersions in aqueous media, might be useful for various biomedical applications.
Asunto(s)
Quitosano/química , Nanoestructuras/química , Materiales Biocompatibles , Biodegradación Ambiental , Biotecnología/métodos , Tampones (Química) , Carbodiimidas/química , Quitina/química , Quitosano/síntesis química , Ácido Cítrico/farmacología , Reactivos de Enlaces Cruzados/química , Reactivos de Enlaces Cruzados/farmacología , Portadores de Fármacos , Concentración de Iones de Hidrógeno , Luz , Espectroscopía de Resonancia Magnética , Malatos/farmacología , Microscopía Electrónica de Transmisión , Modelos Químicos , Peso Molecular , Nanotecnología , Tamaño de la Partícula , Poliaminas/química , Polielectrolitos , Polímeros/química , Dispersión de Radiación , Tartratos/farmacologíaRESUMEN
Bisphosphonates conjugated to fluoroquinolone antibacterials through an intermediate carbon had better activity than conjugates lacking the carbon. Virtually all molar-based activity of these esterified bisphosphonate derivatives was identical to that of its parent. De-esterified free-acid forms retained good activity against most Gram-negative bacteria, but not against Gram-positives. A free-acid derivative remained bound to washed bone and completely inhibited Staphylococcus aureus growth. The more potent parent, ciprofloxacin, failed to bind significantly, and bacterial growth occurred.