APPLICATION OF CURDLAN TO CONTROLLED DRUG DELIVERY .1. THE PREPARATION AND EVALUATION OF THEOPHYLLINE-CONTAINING CURDLAN TABLETS

To study the use of curdlan, a natural beta-1,3-glucan, in drug delive ry, in vitro release studies were carried out with curdlan tablets con taining theophylline. Tablets were readily prepared by compressing thr ee different curdlan and theophylline mixtures, namely, a physical mix ture, spray-dried curdlan particles with theophylline powder, and spra y-dried particles of curdlan/theophylline solution. Drug release from the tablets prepared from spray-dried particles of curdlan/theophyllin e was lowest. The release rate was constant from 1 to 8 hr, and 59% cu mulative release was obtained at 8 hr. Drug release from curdlan table ts was unaffected by pH or various ions; these curdlan tablets might a lso control drug release in vivo after oral administration. Applicatio n of Higuchi's equation indicated that drug release from curdlan table ts was diffusion-controlled. The release profiles of the curdlan table ts were compared to those of a commercial theophylline sustained-relea se tablet.