Coating is one of the effective methods used in controlled release dosage form. Lots ofvariety in the form of a hydrophilic polymer excipient that is used to control the drugrelease many polymers that can be used for coating purposes, but only a few have beenknown to serve as a polymeric coating which functions to control the rate of drugrelease Pregelatinized cassava starch (PCS) is a physically modified starch. The purposesof the study were to improve functionality of PCS with making coprocess composedof PCS and methylcellulose (MC) by proportionally variation, which are 2:1,3:1, and 4:1, as well as to applied co-processed excipient that could retard the drugrelease as coating material of theophylline tablet. Coprocessed excipient characterizedin terms of morphology, particle size distribution, compressibility index, flow rateand angle of repose, thermal analysis, hygroscopicity, gel strength, swelling test, andmoiety analysis.