ketakaolin (Al2O3 2SiO2) was initially prepared by thermal treatment of Kaolinite at 800 1C for 2 h. Sodium silicate solution (waterglass) was prepared by mixing sodium hydroxide, fumed silica and de-ionized water until a clear and viscous solution was formed. A geopolymer paste (Si/Al1⁄41.77, Na2O/Al2O31⁄41.4, H2O/Al2O31⁄414) was prepared by mixing metakaolin, waterglass and the model drug Zolpidem tartate without (Control) or with 1 g of polymer excipient in dissolved or powder form per 6.5 g Metakaolin in a glass mortar until a uniform paste was formed. The paste was molded in cylindrically shaped Teflons molds resulting in pellets of the size 1.5 mm 1.5 mm (diameter height) and in rubber molds resulting in rods for compression strength tests with a corresponding size of 6 mm 12 mm. The geopolymer precursor was cured at 37 1C for 48 h in 100% relative humidity (RH) and stored in an 11% RH dessicator before analysis. The pellets prepared from pastes contain- ing polymers in dissolved form and powder form were named after the polymer