formulation and evaluation of the sustained release matrix tablets : LAP Lambert Academic Publishing : 9786203410747 : 6203410748 : 27 Feb 2021 : The aim of the present research work was to formulate and evaluate the sustained release matrix tablets of Phenylpropanolamine HCl, in order to improve patient compliance and reduce the adverse effect by reducing the dosing frequency. The absence of interaction between the drug and the proposed excipients was confirmed by IR spectroscopy and DSC. The matrix tablets were formulated by wet granulation technique using hydrophilic, hydrophobic, and waxy polymers, alone or in combination. Initial trials indicated that the use of EC and HPMC alone were not helpful in successfully retarding the release, but the combination of both retarded the release up to 8hrs. The post granular addition and coating of EC contributed significantly in retarding the drug release.The granules were evaluated for bulk density, tapped density, Carr's index, Hausner's ra