Design of rolipram-loaded nanoparticles: comparison of two preparation methods

The aim of the present work was to investigate the preparation of nanoparti cles as a potential drug carrier and targeting system for the treatment of inflammatory bowel disease. Rolipram was chosen as the model drug to be inc orporated within nanoparticles. Pressure homogenization-emulsification (PHE ) with a microfluidizer or a modified spontaneous emulsification solvent di ffusion method (SESD) were used in order to select the most appropriate pre paration method. Poly(epsilon -caprolactone) has been used for all preparat ions. The drug loading has been optimized by varying the concentration of t he drug and polymer in the organic phase, the surfactants (polyvinyl alcoho l, sodium cholate) as well as the volume of the external aqueous phase, The rolipram encapsulation efficiency was high (>85%) with the PHF method in a ll cases, whereas with the SESD method encapsulation efficiencies were lowe r (<40%) when lower surfactant concentrations and reduced volume of aqueous phase were used, Release profiles were characterized by a substantial init ial burst release with the PHE method (25-35%) as well as with the SESD met hod (70-90%). A more controlled release was obtained after 2 days of dissol ution with the PHE method (70-90%), no further significant drug release was observed with the SESD method. (C) 2001 Elsevier Science B.V. All rights r eserved.