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Updated: Jul 16, 2026

Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles
Published on: August 28, 2015
Dexamethasone-loaded nanoparticle-coated microparticles: correlation between in vitro drug release and drug transport
R C R Beck1, A R Pohlmann, C Hoffmeister
1Programa de Pós-Graduação em Ciências Farmacêuticas, Porto Alegre, RS, Brazil. ruybeck@smail.ufsm.br
Abstract:
This work reports the preparation of dexamethasone in nanoparticle-coated microparticles and the study of the influence of such microencapsulation on drug absorption across Caco-2 cell monolayers. Nanoparticle-coated microparticles were prepared by spray-drying using nanocapsules (NC) or nanospheres (NS) in aqueous suspensions as coating material. Drug contents ranged from 64 to 134mgg(-1), yields between 49% and 67% and moisture content below 2.0%. SEM and AFM analysis demonstrated that the nanoparticle-coated microparticles (20-53microm) show nanostructures on their surface with a similar diameter compared to the aqueous suspensions. The type of nanocoating material had a significant influence on the drug release profile and on the drug permeation across Caco-2 cells: NC-coated microparticles led to a prolonged release and slower transport across Caco-2 cell monolayers, while the NS-coated microparticles showed a faster release and Caco-2 transport compared to uncoated microparticles. The correlation between the amount of drug permeated and the drug released (%) suggests that the drug absorption from such a delivery system is controlled mainly by the release rate rather than by epithelial permeability. Caco-2 transport studies appear to be a useful characterization tool for the development of microparticulate oral controlled release systems.
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