title: Alginate-poloxamer microparticles for controlled drug delivery to mucosal tissue.
abstract: OBJECTIVE
  The aim of this study was to prepare and characterize novel hydrogel-based delivery systems allowing for the controlled release of drugs to mucosal surfaces.
  
  
  METHODS
  Terbutaline sulfate and bovine serum albumin (BSA)-loaded alginate-poloxamer microparticles were prepared by a w/o-emulsion- and external gelation method. The microparticles were characterized by optical and scanning electron microscopy, laser light diffraction, atomic absorption spectroscopy, energy-dispersive X-ray analysis, via complexation with 1,9-dimethyl methylene blue and using dialysis bags as well as modified Franz diffusion cells for in vitro drug-release measurements.
  
  
  RESULTS
  Using heptane as organic phase, homogeneous and almost spherical microparticles were obtained with a high-loading efficiency (>90%). The resulting drug-release patterns could effectively be adjusted by varying the "alginate:poloxamer" blend ratio. In addition, the particle size, morphology, calcium and chloride content as well as alginate-release rates could be altered. Erosion was the predominant release mechanism for BSA. Special attention needs to be paid to the microparticle recovery procedure, which can significantly affect key properties such as the resulting drug-release patterns.
  
  
  CONCLUSIONS
  The novel hydrogel-based microparticles offering mild conditions for incorporated drugs (e.g., proteins) provide an interesting potential as controlled delivery systems for mucosal surfaces.
authors.affiliation: College of Pharmacy, Freie Universität Berlin, Berlin, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Moebus
authors.forename: Juergen
authors.initials: J
authors.lastname: Siepmann
authors.forename: Roland
authors.initials: R
authors.lastname: Bodmeier
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002712:Chlorides / Q000737:chemistry; D016503:Drug Delivery Systems; D015195:Drug Design; D006536:Heptanes / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry; D008863:Microspheres; D009092:Mucous Membrane / Q000187:drug effects*; D020442:Poloxamer / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000464:Alginates; D002712:Chlorides; D006536:Heptanes; D020100:Hydrogels; D020442:Poloxamer; D012710:Serum Albumin, Bovine; D002118:Calcium