title: Effect of palmitic acid on the characteristics and release profiles of rotigotine-loaded microspheres.
abstract: BACKGROUND
  The initial burst release is a major obstacle to the development of microsphere-formulated drug products.
  
  
  OBJECTIVE
  To investigate the influence of palmitic acid on the characteristics and release profiles of rotigotine-loaded poly(d,l-lactide-co-glycolide) microspheres.
  
  
  METHODS
  Rotigotine-loaded microspheres (RMS) were prepared using the oil-in-water emulsion solvent evaporation technique. The in vitro characteristics of the RMS were evaluated with scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and a particle size analyzer. The in vitro drug release and in vivo pharmacokinetics of the RMS were investigated.
  
  
  CONCLUSIONS
  The SEM results showed that the addition of palmitic acid changed the surface morphology of the microspheres from smooth to dimpled and then to non-smooth as the palmitic acid content increased. DSC revealed the existence of molecularly dispersed forms of palmitic acid in the microspheres. The in vitro and in vivo release profiles indicated that the addition of 5% and 8% palmitic acid significantly decreased the burst release of rotigotine from the microspheres, and the late-stage release was delayed as the palmitic acid content increased across the investigated range (5-15%).
  
  
  CONCLUSIONS
  The addition of palmitic acid to the microspheres significantly affects the release profile of rotigotine from RMS.
authors.affiliation: a School of Pharmacy, Yantai University , Yantai , Shandong Province , China , and.
authors.forename: Aiping
authors.initials: A
authors.lastname: Wang
authors.affiliation: a School of Pharmacy, Yantai University , Yantai , Shandong Province , China , and.
authors.forename: Rongcai
authors.initials: R
authors.lastname: Liang
authors.affiliation: a School of Pharmacy, Yantai University , Yantai , Shandong Province , China , and.
authors.forename: Wanhui
authors.initials: W
authors.lastname: Liu
authors.affiliation: b State Key Laboratory of Long-acting and Targeting Drug Delivery System , Yantai , Shandong Province , China.
authors.forename: Chunjie
authors.initials: C
authors.lastname: Sha
authors.affiliation: b State Key Laboratory of Long-acting and Targeting Drug Delivery System , Yantai , Shandong Province , China.
authors.forename: Youxin
authors.initials: Y
authors.lastname: Li
authors.affiliation: a School of Pharmacy, Yantai University , Yantai , Shandong Province , China , and.
authors.forename: Kaoxiang
authors.initials: K
authors.lastname: Sun
mesh_terms: D000818:Animals; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D008297:Male; D008863:Microspheres; D019308:Palmitic Acid / Q000737:chemistry* / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013764:Tetrahydronaphthalenes / Q000737:chemistry* / Q000493:pharmacokinetics*; D013876:Thiophenes / Q000737:chemistry* / Q000493:pharmacokinetics*
chemical_list: D003692:Delayed-Action Preparations; D013764:Tetrahydronaphthalenes; D013876:Thiophenes; D019308:Palmitic Acid; C047508:rotigotine
keywords: Burst release; characteristics; palmitic acid; rotigotine-loaded microspheres