Sustained release composition comprising a methylcellulose

A sustained release composition for oral administration comprising a physiologically active ingredient mixed with a methylcellulose, wherein:

• the methylcellulose has anhydroglucose units joined by 1-4 linkages and wherein hydroxy groups of anhydroglucose units are substituted with methyl groups such that the s23/s26 is between 0.27 and 0.36,
• s23 is the molar fraction of anhydroglucose units wherein only the two hydroxy groups in the 2- and 3-positions of the anhydroglucose unit are substituted with methyl groups,
• s26 is the molar fraction of anhydroglucose units wherein only the two hydroxy groups in the 2- and 6-positions of the anhydroglucose unit are substituted with methyl groups, and
• the concentration of methylcellulose is from 0.1% to 10% by dry weight of the active ingredient.