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1.
West Indian med. j ; West Indian med. j;58(2): 87-91, Mar. 2009. ilus, graf, tab
Artículo en Inglés | LILACS | ID: lil-672448

RESUMEN

An attempt has been made to localize ranitidine loaded microspheres in the stomach by magnetic means. Since ranitidine undergoes metabolism by microbial enzymes in the intestine, it is ideal to localize the controlled drug delivery system within the stomach to get uniform release and absorption of the drug for the desired period. Gelatin magnetic microspheres loaded with 9.1, 17.9, 26.3 and 33.3% w/w of ranitidine hydrochloride were prepared by emulsification-cross linking technique. The formulated microspheres were characterized by magnetite content, particle size and in vitro drug release. The efficiency of microspheres to be localized in the stomach is tested in vivo in rats. The prepared microspheres were spherical and had a size distribution from 10 to 105 µm. The in vitro study revealed the capability of microspheres to release the drug over a period of 8 to 12 hours, depending on drug loading. The release was found to be diffusion controlled and followed fickian diffusion principle. The in vivo study showed the efficiency of microspheres to be retained in the stomach over a period of 8 hours.


Se ha hecho el intento por localizar las microesferas cargadas de ranitidina en el estómago mediante medios magnéticos. Como que la ranitidina experimenta metabolismo mediante enzimas microbianas en el intestino, resulta ideal localizar el sistema de administración del medicamento controlado dentro del estómago para alcanzar la liberación y absorción uniformes del medicamento por el período deseado. Microesferas de gelatina magnética cargadas con 9.1, 17.9, 26.3 y 33.3% p/p de hidrocloruro de ranitidina, fueron preparadas mediante una técnica de emulsificación-entrecruzamiento. Las microesferas formuladas se caracterizaron por su contenido de magnetita, el tamaño de las partículas y la liberación del medicamento in vitro. La eficiencia de las microesferas a ser localizadas en el estómago se prueba in vivo en ratas. Las microesferas preparadas eran esféricas y tenían una distribución de tamaño de 10 a 105 µm. El estudio in vitro reveló la capacidad de las microesferas para liberar la droga en un período de 8 a 12 horas, en dependencia de la carga de la droga. Se halló que la liberación estaba sujeta difusión controlada y seguía la ley de Fick para la difusión. El estudio in vivo mostró la eficiencia de las microesferas para ser retenidas en el estómago por un período de 8 horas.


Asunto(s)
Animales , Ratas , Antiulcerosos/administración & dosificación , Sistemas de Liberación de Medicamentos/métodos , Magnetismo , Microesferas , Ranitidina/administración & dosificación , Antiulcerosos/metabolismo , Gelatina , Tamaño de la Partícula , Ranitidina/metabolismo , Ratas Wistar , Estómago/metabolismo
2.
West Indian Med J ; 58(2): 87-91, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21866590

RESUMEN

An attempt has been made to localize ranitidine loaded microspheres in the stomach by magnetic means. Since ranitidine undergoes metabolism by microbial enzymes in the intestine, it is ideal to localize the controlled drug delivery system within the stomach to get uniform release and absorption of the drug for the desired period. Gelatin magnetic microspheres loaded with 9.1, 17.9, 26.3 and 33.3% w/w of ranitidine hydrochloride were prepared by emulsification-cross linking technique. The formulated microspheres were characterized by magnetite content, particle size and in vitro drug release. The efficiency of microspheres to be localized in the stomach is tested in vivo in rats. The prepared microspheres were spherical and had a size distribution from 10 to 105 microm. The in vitro study revealed the capability of microspheres to release the drug over a period of 8 to 12 hours, depending on drug loading. The release was found to be diffusion controlled and followed fickian diffusion principle. The in vivo study showed the efficiency of microspheres to be retained in the stomach over a period of 8 hours.


Asunto(s)
Antiulcerosos/administración & dosificación , Sistemas de Liberación de Medicamentos/métodos , Magnetismo , Microesferas , Ranitidina/administración & dosificación , Animales , Antiulcerosos/metabolismo , Mucosa Gástrica/metabolismo , Gelatina , Tamaño de la Partícula , Ranitidina/metabolismo , Ratas , Ratas Wistar
3.
Food Chem Toxicol ; 44(9): 1585-9, 2006 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16730111

RESUMEN

Strychnos pseudoquina St. Hil. is a native plant of the Brazilian Savannah, used in popular medicine to treat a number of conditions. Since it contains large quantities of alkaloids with proven antiulcer activity, we tested the genotoxic potential of crude extracts and fractions containing alkaloids and flavonoids from the leaves of this plant, on Salmonella typhimurium and performed the micronucleus test on peripheral blood cells of mice treated in vivo. The results showed that the methanol extract of the leaves of S. pseudoquina is mutagenic to the TA98 (-S9) and TA100 (+S9, -S9) strains of Salmonella. The dichloromethane extract was not mutagenic to any of the tested strains. Fractions enriched with alkaloids or flavonoids were not mutagenic. In vivo tests were done on the crude methanol extract in albino Swiss mice, which were treated, by gavage, with three different doses of the extract. The highest dose tested (1800 mg/kgb.w.) induced micronuclei after acute treatment, confirming the mutagenic potential of the methanol extract of the leaves of S. pseudoquina. In high doses, constituents of S. pseudoquina compounds act on DNA, causing breaks and giving rise to micronuclei in the blood cells of treated animals.


Asunto(s)
Antiulcerosos/toxicidad , Micronúcleos con Defecto Cromosómico/efectos de los fármacos , Mutágenos/toxicidad , Extractos Vegetales/toxicidad , Salmonella typhimurium/efectos de los fármacos , Strychnos , Administración Oral , Animales , Antiulcerosos/metabolismo , Fraccionamiento Químico , Relación Dosis-Respuesta a Droga , Femenino , Masculino , Metanol/química , Ratones , Pruebas de Micronúcleos , Mutágenos/metabolismo , Extractos Vegetales/metabolismo , Plantas Medicinales/química , Reticulocitos/efectos de los fármacos , Proteína Ribosómica S9 , Proteínas Ribosómicas/efectos de los fármacos , Proteínas Ribosómicas/metabolismo , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo , Strychnos/química
4.
J Ethnopharmacol ; 81(1): 111-5, 2002 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12020934

RESUMEN

The labdane diterpene solidagenone 1 and its semisynthetic and biotransformations products 2-7 were assessed for gastroprotective effect in the HCl.EtOH-induced lesions in mice. At 100 mg/kg, solidagenone presented a statistically significant gastroprotective effect (P<0.05) comparable to lansoprazole at 20 mg/kg. The presence of the furan ring was required for the activity of solidagenone while hydroxylation at C-3 or C-6 afforded products with different activity associated with the stereochemistry. Solidagen-6beta-ol 7 and 3alpha-hydroxysolidagenone 2 presented higher activity than solidagenone itself, while its epimers were inactive.


Asunto(s)
Antiulcerosos/farmacología , Diterpenos/farmacología , Furanos/farmacología , Naftalenos/farmacología , Solidago/química , Gastropatías/inducido químicamente , Gastropatías/prevención & control , Animales , Antiulcerosos/metabolismo , Antiulcerosos/uso terapéutico , Biotransformación , Modelos Animales de Enfermedad , Diterpenos/química , Diterpenos/metabolismo , Diterpenos/uso terapéutico , Etanol/farmacología , Furanos/química , Furanos/metabolismo , Furanos/uso terapéutico , Ácido Clorhídrico/farmacología , Espectroscopía de Resonancia Magnética , Ratones , Estructura Molecular , Naftalenos/química , Naftalenos/metabolismo , Naftalenos/uso terapéutico , Fitoterapia , Gastropatías/tratamiento farmacológico , Gastropatías/patología , Úlcera Gástrica/inducido químicamente , Úlcera Gástrica/tratamiento farmacológico , Úlcera Gástrica/patología , Úlcera Gástrica/prevención & control
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