FORMULATION AND RELEASE KINETICS OF SUSTAINED-RELEASE PHENYLPROPANOLAMINE HYDROCHLORIDE GRANULES AND TABLETS

Sustained release phenylpropanolamine hydrochloride (PPH) granules and tablets were prepared using HPMC, HPMC and SCMC, Eudragit RS, Eudragi t RS+L or HPMC + Eudragit RS matrices. The release pattern of PPH from the prepared granules and tablets was found to be in the following or der HPMC > HPMC + SCMC > RS > RS+1 > HPMC + RS. The results revealed t hat, although the drug concentration was kept constant in all the prep ared granules and tablets, the drug release from these formulations wa s clearly different and depends mainly on the type of matrix used. The presence of Eudragit L with Eudragit RS and Eudragit RS with HPMC res ulted in a marked decrease in the drug release compared with that obta ined from the matrix containing HPMC or Eudragit RS alone. The release data of PPH from the prepared granules and tablets were treated mathe matically according to zero order, first order, Langenbucher, modified Langenbucher and Higuchi models, The results revealed that no one mod el was able adequately to describe the drug release profiles from thes e formulations. In-vivo studies in human volunteers showed that, the p eak urinary excretion of PPH occurred over a sustained period from 2 t o 6.5 hr in case of HPMC + SCMC tablets and from 2 to 10 hr in case of either RS + L or HPMC + RS tablets.