Sustained drug release composition

A solid, monolithic sustained release pharmaceutical composition having an outer surface, the composition comprising:

• a. a sustained release matrix having a solvent accessible surface, the matrix comprising from about 15% to about 85% by weight of a controlled release excipient selected from the group consisting of cross-linked high amylose starch, hydroxypropylmethylcellulose and a combination thereof;
• and
• b. an effective amount of at least one pharmaceutically active agent disposed within the matrix,
• the composition having a hardness of greater than 100 N, the outer surface of the composition optionally defining at least one score that permits the composition to be fractured along the score,
• wherein the composition, if broken into at least two subunits, at least one of the subunits and an intact form of the composition have substantially the same release kinetics of the active agent disposed therein and their dissolution profiles have a similarity factor of at least 60%, and wherein, if the outer surface comprises a coating surrounding the matrix, the coating does not affect the release kinetics of the active agent disposed within the matrix.