Preparation and characterization of hydrogenated soybean oil as a controlled release regulator for metoprolol tartrate pellets

Abstract

The aims of this study were to prepare hydrogenated soybean oil (HSO) meeting the pharmaceutical specifications and to use tartrate pellets. Hydrogenation process was performed in a 2-liter batch agitated reactor with a 4-bladed disk turbine. A23 central composite design preparation.The reaction of catalyst, pressure. The was at 0.075% weight nickel, 0.86 MPa of pressure and 408 K of temperature. Increasing temperature increas ed the acid value of products. All products prepared at the optimum condition had quality conforming to hydrogenated vegetable oil type I USP 27/ NF 22. By DSC, HSM and XRD studies, HSO showed three main polymorphs namely α -, β ́- and β -form, listed in order of increasing thermodynamic stability. Aged HSO showed β ́- and β -form that are transformed to α - and β ́-form after melting. HSO was stable under high heating temperature in the range of 80-120°C and heat exposure at 100°C for 1 hour. Controlled release metopr olol pellets were prepared by hot melt fluid bed coating technique. The drug was dispersed in melted HS O and directly sprayed on nonpareils. The poor wettability of HSO enhanced the buoyancy of coated pellets in the in vitro study. Drug size fraction affected the size distribution of so lidified lipid droplets, coating structure and drug release. Increasing coating amount or a dding an additive revealed the decreased drug release. Drug release from coated pellets followe d a bi-phasic square-root-of-time kinetic, i.e., a burst release at the beginning (within the firs t 1 hour) followed by a slow release for 7 hours. The burst release is attributable to amount of coating, drug size fraction and to the inert additive which was added. Coated pellets showed three main polymorphs of HSO. Tempering process enhanced the β -form formation as crystal growth on the surface of coated pellets and revealed the increased drug release. In conclusion, HSO could be a promising material to control drug release in controlled release pellets based on its lipophilicity and buoyancy properties.