Mechanisms of potassium chloride release from compressed, hydrophilic, polymeric matrices: effect of entrapped air.

The release of potassium chloride from hydroxypropyl methylcellulose matrices was investigated for tablets prepared with several different compression forces. It was determined that the release kinetics for these systems deviates significantly from the classical t1/2 dependence. This behavior was attributed to air entrapped in the matrix during preparation. Removal of the air prior to release restored the traditional t1/2 behavior.