MICROCRYSTALLINE CELLULOSE-SUCROSE ESTERS AS TABLET MATRIX FORMING AGENTS

A new tablet matrix system containing micracrystalline cellulose and s ucrose esters is described. Theophylline monohydrate and ibuprofen wer e chosen as model drugs. Theophylline tablets compressed directly usin g 5% (w/w) sucrose stearate esters (S170, S770, S1570), or sucrose pal mitate ester P1570 and microcrystalline cellulose showed a slight reta rdation of drug release with P1570 and S170, respectively. Increasing the concentration of S170 up to a value of 15% decreased the release t o a value of 60% after 3 h. Increasing the concentration of P1570 to 1 0% showed a dramatic decrease in dissolution as only 30% was released after 3 h. Thermal treatment above the melting temperature range of th e palmitate sucrose ester (P1570 5% w/w)-microcrystalline cellulose-th eophylline granules decreased the dissolution rate dramatically, demon strating 80% release after 8 h. The duration of thermal treatment did not have any influence on the drug release profile. Increasing the con centration of palmitate sucrose ester from 5 to 10% decreased the rele ase progressively to a value of about 50% after 8 h. Very similar rele ase patterns were observed when S1570 was used instead of P1570. The s ucrose ester S770 performed less well;as a matrix forming agent with t he 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 h ave some influence on the dissolution rate of the theophylline matrix tablet.