Studies on Production of Higher Functional Pharmaceutical Preparations by Using Various Additives. III. Application of Hollow Glass Beads for Intragastric Floating Granules.

Abstract

In our previous paper, we developed intragastric floating and sustained release granules using the characteristically porous structure of calcium silicate. In this paper, we investigated the preparation of floating granules using hollow glass beads (GB, density 0.15 g/cm3) as a carrier and introducing them to the solid dispersion in order to produce a higher floating ability. A 20/5/75 weight ratio of oxprenolol hydrochloride (OXP) as a model drug, hydroxypropylcellulose (HPC) and ethylcellulose (EC) was dissolved in ethanol. Zero, 20, 40, 60 and 80 weight percent of GB to the total weight of OXP, HPC and EC were added to the ethanol solution, and the solvent was then evaporated by rotating the vessel at 50°C. Several types of solid dispersion which contain suspended and dispersed GB were obtained. The granules having different GB contents were obtained after being dried at 80°C in vacuo and were crushed using a coffee mill for sieving. The density, floating property and drug release profile of the granules were than studied. The density of granules without GB, namely the solid dispersion granules, was 1.18 g/cm3 and therefore did not have floating properties. The densities of all types of granules containing GB were less than 1 g/cm3 and these granules floated for a long time in the floating test. It was found that release rates of OXP from granules decreased with decreasing GB content, since the surface area of granules was decreased and a thick layer of solid dispersion was formed. These results suggest that it is possible to prepare floating granules by using GB.