| The purpose of this research project was to use a moist granulation technique (MGT) to develop controlled release tablets. Acetaminophen, a poorly compressible, sparingly water-soluble drug was used as the model drug. Hydroxypropylcellulose was used as the rate-controlling agent. A model formulation exhibiting the desired degree of controlled release was developed. This formulation contained 44.6% w/w hydroxypropylcellulose. Drug release from the model formulation was Higuchi, diffusion controlled. The effect of formulation factors on controlled release tablets was studied and it was observed that the process is robust enough to allow variation in formulation factors without affecting drug release. When acetaminophen in the model formulation was replaced with phenylpropanolamine HCl, which is very water soluble, the mechanism of release was unchanged. Changing the polymer type from hydroxypropylcellulose to hydroxypropyl methylcellulose did not affect drug release. Thus, moist granulation technique can be applied in general to the development of controlled release dosage forms. |
