Sustained Release of Ibuprofen from Polyelectrolyte Encapsulated Mesoporous Carriers

Abstract

Polyelectrolyte multilayers are receiving much attention due to their insolubility and due to structural responses induced in them by changes in solution properties such as, for example, temperature, pH or ionic strength. These characteristics make polyelectrolyte multilayers highly interesting in encapsulation technology and controlled delivery applications. However, producing dry, biocompatible formulations for storage of low molecular weight substances poses a challenge. One possibility is to make use of a well-defined mesoporous inorganic carrier material as host for the model substance (in our case ibuprofen). Control over release properties are enabled by polyelectrolyte encapsulation of the inorganic carrier. We built such multilayers through consecutive deposition of PAH and PSS on top of a first layer ofr PEI. These layers were adsorbed either in presence or absent of ibuprofen. The influence of long time storage, 2 years, of the samples was also investigated. The polyelectrolyte multilayer structure was investigated in detail by Dual Polarization Interferometry (DPI), and we use these data to interpret the measured release profiles.