title: Formulation of sustained-release verapamil HCl and diltiazem HCl semisolid matrix capsules.
abstract: Semisolid matrix capsule formulations of verapamil HCl and diltiazem HCl prepared by hot-melt capsule filling are an especially appealing and simple way to make sustained-release formulations. Semisolid matrices of Gelucire 50/13 and stearic acid combination eroded and disintegrated at various rates, depending on the combination of waxes, and drug release rates were dependent on storage time (2.5 years) and temperature. Semisolid matrices of combinations of only Gelucire 50/13 and cetyl alcohol eroded at a rate much less than combinations of Gelucire 50/13 and stearic acid. The drug release mechanism from Gelucire 50/13: stearic acid matrices involved diffusion and erosion, whereas Gelucire 50/13 and cetyl alcohol matrices exhibited a diffusion mechanism only. A combination of Gelucire 50/13 with cetyl alcohol is more effective than stearic acid in appropriately extending verapamil HCl release from semisolid matrix capsules. The semisolid matrix formulations studied are sensitive to dissolution stirring speeds.
authors: Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR, USA. nguyenngocchien@yahoo.com
authors: Chien N
authors: CN
authors: Nguyen
authors: J Mark
authors: JM
authors: Christensen
authors: James W
authors: JW
authors: Ayres
mesh_terms: D002214:Capsules; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004110:Diltiazem / Q000008:administration & dosage / Q000737:chemistry*; D012995:Solubility; D014700:Verapamil / Q000008:administration & dosage / Q000737:chemistry*
chemical_list: D002214:Capsules; D003692:Delayed-Action Preparations; D014700:Verapamil; D004110:Diltiazem