Cross-linked high amylose starch for use in controlled-release pharmaceutical formulations and processes for its manufacture

The present invention relates to a novel form of cross-linked high amylose starch and processes for its manufacture. Such cross-linked high amylose starch is useful as an excipient in a controlled-release pharmaceutical formulation when compressed with a pharmaceutical agent(s) in a tablet. Such cross-linked high amylose starch is prepared by (a) cross-linking and chemical modification of high amylose starch, (b) gelatinization, and (c) drying to obtain a powder of said controlled release excipient. In a preferred embodiment, such cross-linked high amylose starch is prepared in following steps: (1) granular cross-linking and additionally chemical modification (e.g., hydroxypropylation) of high-amylose starch; (2) thermal gelatinization of the starch from step (1); and (3) drying the starch from step (2) to yield a powder capable of being used as a controlled release excipient.