GRANULATION OF ASPIRIN SUSTAINED-RELEASE FORMULATION WITH HYDROXYPROPYLMETHYLCELLULOSE AS RATE-CONTROLLING AGENT

Wet granulation using a high-speed mixer was studied with hydroxypropy l methylcellulose (HPMC) as a rate-controlling polymer and aspirin as a model drug. i) High and low HPMC viscosity both produce granulations with high density; high HPMC content gives small density. ii) At low levels, HPMC viscosity and HPMC content contribute separately and nega tively to geometric median diameter; at high levels, the synergistic i nteraction of these two factors contributes most. iii) At very high vi scosity range, the yield does not change as HPMC content increases; at other ranges of HPMC viscosity, yield decreases as HPMC content incre ases. At any HPMC content level, an HPMC viscosity region gives maximu m yield. (iv) Using the optimization statistics methodology, an optima l region of HPMC content and HPMC viscosity was found. Within this reg ion, expected granulations will be produced.