The sustained release properties of regular and waxy rice starches and their derivatives were studied in tablets. The starches were cross-linked to different levels with epichlorohydrin, and the sustained release properties, swelling power, and rheological characteristics of the matrices prepared were determined. Propranolol hydrochloride was used as a model drug. The sustained release properties of waxy rice starch improved with increasing cross-linking levels, whereas cross-linking had little impact on the functionality of regular rice starch matrices. There was an increase in swelling power for both regular and waxy rice starches as cross-linking levels increased. Both starches showed an increase in the storage modulus when cross-linking was increased, with the regular rice starch matrices showing greater differences among samples. Regular rice starch matrices showed an independence of frequency as cross-linking increased, indicating a “true gel” characteristic, whereas waxy rice matrices behaved as a “weak gel.” Both regular and waxy rice starches displayed a decrease in creep and recovery profiles with an increase in cross-linking level. Waxy rice starch showed potential as a sustained release agent in tablets.
Peluso, Christopher F.; Onofre, Fernanda O.; and Wang, Ya-Jane
"Application of cross-linked rice starches as drug delivery matrices in monolithic tablets,"
Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences. University of Arkansas System Division of Agriculture. 10:29-36.
Available at: http://scholarworks.uark.edu/discoverymag/vol10/iss1/8