Tablet formation and release from matrix tablets manufactured with cellulose acetate

Abstract

Cellulose acetate has been successful in the production of matrix tablets but contradictory results exist also. Therefore, in this study it is used to elucidate the dependency of drug release from tablet formation and the factors influencing the microstructure of the tablet, such as densification, different particle size fractions, the dwell time during tableting and different drug concentrations. Tablets are produced on a single punch machine and on a hydraulic press. The tableting behaviour is judged from Heckel plots. Elastic recovery and crushing strength are measured. The resulting tablets are analysed by SEM, disintegration studies are performed and drug release is analysed. The produced tablets are of high robustness, tableting behaviour is plastoelastic. A high densification, that means a maximum relative density (ϱ rel, max) of at least 0.975 and particles of all sizes are necessary to produce tablets which are stable during disintegration studies for more than 8 h. Film-like structures were formed by partial fusion during tableting at temperatures higher than the glass transition temperature of the material. A reorganisation of the material occurred. A dwell time of 10 or 20 s improved the formation of these structures. Tablets produced at high ϱ rel, max or with longer dwell times resulted in controlled release tablets.