Abstract: The present invention provides a controlled release device for sustained or pulsatile delivery of pharmaceutically active substances for a predetermined period of time. This invention further provides such device in which sustained or pulsatile delivery is obtained by the unique blend and intimate mixture of pharmaceutically active substances with a microbial polysaccharide and uncrosslinked linear polymer and optionally a crosslinked polymer and/or lipophillic polymer and/or saturated polyglycolyzed glyceride. The invention also provides a process for the manufacture of such devices and pharmaceutical compositions containing the same.