A new tablet matrix system containing micracrystalline cellulose and sucrose esters is described. Theophylline monohydrate and ibuprofen were chosen as model drugs. Theophylline tablets compressed directly using 5% (w/w) sucrose stearate esters (S170, S770, S1570), or sucrose palmitate ester P1570 and microcrystalline cellulose showed a slight retardation of drug release with P1570 and S170, respectively. Increasing the concentration of S170 up to a value of 15% decreased the release to a value of 60% after 3 h. Increasing the concentration of P1570 to 10% showed a dramatic decrease in dissolution as only 30% was released after 3 h. Thermal treatment above the melting temperature range of the palmitate sucrose ester (P1570 5% w/w)-microcrystalline cellulose-theophylline granules decreased the dissolution rate dramatically, demonstrating 80% release after 8 h. The duration of thermal treatment did not have any influence on the drug release profile. Increasing the concentration of palmitate sucrose ester from 5 to 10% decreased the release progressively to a value of about 50% after 8 h. Very similar release patterns were observed when S1570 was used instead of P1570. The sucrose ester S770 performed less well;as a matrix forming agent with the microcrystalline cellulose. Dissolution experiments with ibuprofen as model drug indicated the possibility of using the matrix with other drugs. Hydrogen bond formation could be the basic mechanism of matrix formation between microcrystalline cellulose and the sucrose esters. Finally, the pH value, ionic strength and rotational speed seemed to have some influence on the dissolution rate of the theophylline matrix tablet.
