RESUMEN
Most studies involving binders are concerned with the properties of the final product. Very little has been done at comparing the mechanical properties of the granules, the force required to crush the tablets and the compression behavior. The aim of this investigation was to study the effect of different concentrations of five binders namely gelatin, PVP, methylcellulose, syrup and Eudragit E on the mechanical and physical properties of calcium carbonate granules and correlating that with the characteristics of the corresponding tablets. A template method was used for the preparation of calcium carbonate granules. The wet granules were dried for 34 h in air oven at 60 degrees C and were conditioned for a minimum of 2 h at 50% relative humidity before testing or tableting as this corresponds approximately to ambient conditions. The granules, were separated into different size fractions using the sieve analysis method, and were then measured for crushing strength (K), friability (%), flow ability, bulk volume and tap density. The granules possessing the best mechanical and physical characteristics were used for tableting. The compact obtained were also evaluated for both mechanical and physical properties. It was found that increasing the binder concentration was followed by an increase in the mean particle diameter, harder granules (-kt = ln Wa divided by W + Wb . db divided by W . da) and reduction in tap density. Except for those prepared with 2% methylcellulose and 30% syrup, all tablets prepared from granules with optimum properties are found to satisfy U.S.P. requirements of weight, thickness, disintegration time and mechanical properties.
Asunto(s)
Carbonato de Calcio , Carbonato de Calcio/análisis , Excipientes , Dureza , Tamaño de la Partícula , Polvos , ComprimidosRESUMEN
Three methods were employed for the solubilization of indometacin as an example of antirheumatic drugs, employing:--Non-ionic surface-active agents such as Tween 80 and 40, Myrj 53 and Brij 99,--urea and sodium citrate--urea-indometacin coprecipitate. The solubility of indometacin by nonionic surface active agents was in the following order: Tween 80 and Brij 99 greater than Tween 40 greater than Myrj 53. The efficiency of solubilization by these surfactants decreased as the polyoxyethylene chain increased. Urea increases the solubility of indometacin due to enhancing the solvation of the drug by water. Up to a concentration of 0.2 M sodium citrate increases the solubility of indometacin, followed by a sharp decline in the solubility by increasing its concentration of sodium citrate. Urea-indometacin coprecipitate show slight increase in the solubility of the drug.