Swelling and Drug Release Studies from Hydrophilic Matrices Containing Combination of Different Grades of Hydroxyl Propyl Methylcellulose

Polymers are very popular and widely used in formulating sustained release tablets because they are
excellent drug carriers. The current study examines the drug release from the hydrophilic matrices
prepared using combination of different grades of hydroxyl propyl methylcellulose (HPMC), viz,
HPMCK4M, HPMCK15M and HPMCK100M. The results indicate that swelling and release profiles
were affected by concentration and viscosity grade of the polymer. This swelling action of HPMC of
different grades in turn is controlled by the rate of water uptake into the matrices. An inverse
relationship exists between the drug release rate and matrix-swelling rate. This implies that rational
combination of the different grades tends to provide quite regulated release of drug. The swelling
behavior is therefore useful in predicting drug release.