RESUMEN
Objetivos: En el presente trabajo se describe el desarrollo de comprimidos matriciales de clorhidrato de diltiazem. Métodos: Se obtienen comprimidos matriciales mediante el uso de goma guar y HPMC. Se estudian distintas formulaciones en las que se cambia la composición de estos materiales matriciales como controladores de la cesión. Los comprimidos se prepararon por el método de granulación húmeda y se evaluaron uniformidad de contenido, índice de hinchamiento, estabilidad y velocidad de liberación. Resultados: La capacidad de hinchamiento aumenta con el porcentaje utilizado de HPMC. Las formulaciones F7, F8 y F9 son las que muestran mejores características de liberación. Los estudios de estabilidad de la formulación seleccionada demuestran una buena resistencia a la rotura, capacidad de hinchamiento y control de la velocidad de disolución durante el estudio de estabilidad. Conclusiones: Las formulaciones F7, F8 y F9 tienen unas buenas propiedades de control de liberación del fármaco durante al menos 8 horas. La cinética de liberación se pueden ajustar a un orden cero(AU)
Aim: The present investigation concerns the development of controlled release matrix tablet of Diltiazem HCl. Methods: Matrix tablet of Diltiazem HCl was formulated by using HPMC and Guar gum as a polymeric matrix forming materials in various concentrations (%w/w) to study their ability to retard the release. The tablets were prepared by wet granulation method and evaluated for physical properties, content uniformity, swelling index, stability and in-vitro drug release. Results: Swelling was increased as the concentration and viscosity of HPMC increases. Tablets formulated using guar gum and HPMC alone were gave initial burst effect followed by controlled release for 8 hr. It was evident from the study that the formulationsF7,F8 &F9 have optimum swelling index and in vitro drug release up to 44% in 8hrs. The stability studies of optimized batch showed that there was no change in hardness, swelling index and in-vitro release up to 12 weeks. Conclusions: The batches F7, F8 and F9 possessed the high potential to release the drug gradually for more than 8 hours. The zero-order release kinetic indicates concentration independent drug release ensuring that the formulated tablet showed promising result to be a sustained release formulation(AU)
Asunto(s)
Preparaciones de Acción Retardada/farmacología , Diltiazem/farmacología , Diltiazem/administración & dosificación , Antihipertensivos/administración & dosificación , Estabilidad de MedicamentosRESUMEN
The objective of the present study was to evaluate the effect of sintering condition on matrix formation and subsequent drug release from polymer matrix tablet for controlled release. The present study highlights the use of a microwave oven for the sintering process in order to achieve more uniform heat distribution with reduction in time required for sintering. We could achieve effective sintering within 8 min which is very less compared to conventional hot air oven sintering. The tablets containing the drug (propranolol hydrochloride) and sintering polymer (eudragit S-100) were prepared and kept in a microwave oven at 540 watt, 720 watt and 900 watt power for different time periods for sintering. The sintered tablets were evaluated for various tablet characteristics including dissolution study. Tablets sintered at 900 watt power for 8 min gave better dissolution profile compared to others. We conclude that microwave oven sintering is better than conventional hot air oven sintering process in preparation of controlled release tablets.
RESUMEN
[reaction: see text] Vanadium pentoxide very effectively promotes the bromination of organic substrates, including selective bromination of some aromatics, by tetrabutylammonium bromide in the presence of hydrogen peroxide; mild conditions, high selectivity, yield, and reaction rate, and redundancy of bromine and hydrobromic acid are some of the major advantages of the synthetic protocol.
RESUMEN
[reaction: see text] Aldehydes, in the presence of methanol, undergo oxidative transformation to the corresponding esters upon treatment with catalytic amounts of vanadium pentoxide in combination with oxidant hydrogen peroxide. Mild reaction conditions, shorter reaction times, high efficiencies, cost-effectiveness, and facile isolation of the desired products make the present methodology a practical alternative.
RESUMEN
TBDMS, THP, and DMT ethers are efficiently deprotected with tetrabutylammonium tribromide in methanol. The apparent order of stability of different protecting group is phenolic TBDMS > 1 degrees OTBDPS > 2 degrees OTBDMS > 2 degrees OTHP > 1 degrees OTHP > 1 degrees OTBDMS > 1 degrees ODMT. TBDMS ether has been cleaved selectively in the presence of isopropylidine, Bn, Ac, Bz, THP, and TBDPS groups. This method is high yielding, fast, clean, safe, cost-effective, and therefore most suitable for practical organic synthesis.