ABSTRACT
The present investigation targets to develop a simple, specific, sensitive and accurate reverse phase high performance liquid chromatographic (RP-HPLC) method in human plasma for the estimation of metformin HCl and propranolol HCl from bulk drug and also from the marketed products. Human plasma samples were subjected to correct procedure for protein precipitation by methanol and protein free plasma samples were directly injected into HPLC C18 column. Chromatographic determination was performed on a reversed phase C18 column (3.9 mm X 300 mm, particle size 5 μm) using a mixture of acetonitrile and 0.1M pH 4.5 potassium dihydrogenortho phosphate buffer (mL) (40:60) at a flow rate of 0.8 mL/min and maintained at a pressure of 140 to 150 Kg/cm2. The retention time for metformin HCl and propranolol HCl was found to be 9.084 min and 6.132 min respectively at 232 nm without any interference of endogenous compounds in the plasma. The method was linear in the range between 50-2000 ng/mL. The peak areas were reproducible as indicated by low coefficient of variation. It was found that the excipients in the tablet dosage form do not interfere in the quantification of active drug by proposed method.
ABSTRACT
The aim of the present investigation was to formulate thermally sintered floating tablets of propranolol HCl, and to study the effect of sintering conditions on drug release, as well as their in vitro buoyancy properties. A hydrophilic polymer, polyethylene oxide, was selected as a sintered polymer to retard the drug release. The formulations were prepared by a direct compression method and were evaluated by in vitro dissolution studies. The results showed that sintering temperature and time of exposure greatly influenced the buoyancy, as well as the dissolution properties. As the sintering temperature and time of exposure increased, floating lag time was found to be decreased, total floating time was increased and drug release was retarded. An optimized sintered formulation (sintering temperature 50°C and time of exposure 4 h) was selected, based on their drug retarding properties. The optimized formulation was characterized with FTIR and DSC studies and no interaction was found between the drug and the polymer used.
El propósito de la presente investigación fue la elaboración de tabletas flotantes de HCL propanolol térmicamente sinterizadas y estudiar los efectos de las condiciones de sinterización sobre la liberación de la droga, así como sobre sus propiedades de flotabilidad in vitro. Se seleccionó un polímero hidrofílico, el óxido de polietileno, como polímero sinterizado, para retardar la liberación de la droga. Las fórmulas se prepararon mediante un método de compresión directa y se evaluaron mediante estudios de disolución in vitro. Los resultados demostraron que la temperatura de sinterización y el tiempo de exposición tuvieron una gran influencia sobre las propiedades de flotabilidad y de disolución. Se encontró que el intervalo de retardo en la flotación disminuyó, el tiempo total de flotación aumentó y se retardó la liberación de la droga, a medida que aumentaron la temperatura de sinterización y el tiempo de exposición. Se seleccionó una fórmula óptima de sinterización (temperatura de sinterización de 50°C y tiempo de exposición de 4 h), basados en las propiedades retardativas sobre la droga. La fórmula sinterizada se caracterizó mediante estudios FITR y DSC y no se encontró ninguna interacción entre la droga y el polímero utilizado.