GRAVIMETRIC CHARACTERIZATION OF THE SURFACE-PROPERTIES OF A POROUS DRUG CARRIER

The gas adsorption method is the most common means to characterise the topology of solid surfaces with regard to its use as an adsorbent. Ad sorption isotherms are determined advantageously using a vacuum microb alance: Thermogravimetric techniques allow the observation of sample d egassing and its optimization. The dry mass is determined in situ, the mass of gas adsorbed is measured directly and different gases can be used without calibration. From the isotherm the pore size distribution s, specific surface area, fractal dimension and density can be derived . Commercially available gravimetric sorption apparata and vacuum bala nces as well as software for data evaluation are reviewed in tables. T he sorption analysis of an aluminum oxide is presented. The porous mat erial was used as a matrix for a slow drug release.