Hydrophobic Aerosils as Dry Coating Agents for Sustained-Release Formulations

Abstract

An innovative and simple dry coating process for formulation of oral sustainedrelease dosage forms was developed. A hydrophobic aerosil (Aerosil® R972) was investigated as a dry coating agent. Aerosil® R972 particles adhered to the surface of acetaminophen particles upon dry coating. The release rate of the drug decreased with increased concentrations of aerosil. The release of acetaminophen from dry coated mixtures in capsules followed a square root of time release for the first 2 hours followed by zero-order release. A first-order relationship was found between the release rate and concentration of Aerosil® R972 in dry coated mixtures.