Evaluation of a Hydrophobic–Hydrophilic (Hydrogenated Castor Oil-Gum Tragacanth) Matrix using Propranolol Hydrochloride as Test Drug

An evaluation of propranolol hydrochloride release from hydrogenated castor oil–gum tragacanth matrices was carried out. The pH of the dissolution medium was found to affect propranolol hydrochloride release from such matrices. Acidic pH was found to enhance release while alkaline pH retarded release. This was attributed to possibly the effect of gum tragacanth matrix material or the propranolol hydrochloride itself. Either square root of time kinetics or first order kinetics could explain propranolol hydrochloride release mechanism from the hydrogenated castor oil–gum tragacanth matrices. Addition of hydrophobic hydrogenated castor oil matrix material to the hydrophilic gum tragacanth matrix was found to enhance release. This was attributed to possibly the disruption of the gum tragacanth matrix by the hydrophobic hydrogenated castor oil matrix material. Although gum tragacanth is primarily a hydrophilic material, it was found to have better release sustaining characteristics than the hydrophobic matrix material hydrogenated castor oil. Keywords : Hydrogenated castor oil, gum tragacanth, matrix, hydrophobic, hydrophilic East and Central African Journal of Pharmaceutical Sciences Vol. 10 (3) 2007: pp.68-71