title: Development of a modified-release pellets formulation--with metoprolol tartrat and kinetic aspects of in vitro release.
abstract: OBJECTIVE
  The development of a new pellets formulation which is able to modulate the release of metoprolol tartrate, an active pharmaceutical ingredient very soluble in water and therefore very difficult to process.
  
  
  METHODS
  Two types of different viscosity grade hydroxypropyl methylcellulose (Methocel K100; HPMC 15.000) and Eudragit NE30D are used as prolonged drug release agents, thus resulting in three formulations which have been prepared in form of pellets, in a conventional coating pan. The obtained pellets are characterized and compared in terms of: particles size distribution, drug loading efficiency, drug content and kinetic of in vitro drug release.
  
  
  RESULTS
  Lower amounts of Eudragit NE30D (7.5%) determine more uniform size distributions of particles. Drug content and charging efficiency is higher in case of fractions ranging in size from 0.80 to 1.25 mm. The combination of HPMC 15000 with 10% Eudragit NE30D leads to a prolongation for a period of 11.5 hours of metoprolol tartrate release. Release kinetics analysis was performed by fitting the in vitro release profile with different kinetic models.
  
  
  CONCLUSIONS
  It was developed a pellets formulation that release in vitro the metoprolol tartrate in an extended mode, with Korsmeyer-Peppas kinetic-type.
authors.affiliation: University of Medicine and Pharmacy from Târgu Mureş, Romania, Department of Pharmaceutical Technology.
authors.forename: Nicoleta
authors.initials: N
authors.lastname: Todoran
authors.forename: Adriana
authors.initials: A
authors.lastname: Ciurba
authors.forename: Stela
authors.initials: S
authors.lastname: Al Hussein
authors.forename: Luminiţa
authors.initials: L
authors.lastname: Lazar
authors.forename: V
authors.initials: V
authors.lastname: Ion
authors.forename: Paula
authors.initials: P
authors.lastname: Antonoaea
mesh_terms: D000959:Antihypertensive Agents / Q000138:chemical synthesis* / Q000493:pharmacokinetics*; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004339:Drug Compounding / Q000379:methods; D065347:Hypromellose Derivatives / Q000138:chemical synthesis*; D066298:In Vitro Techniques; D008790:Metoprolol / Q000138:chemical synthesis* / Q000493:pharmacokinetics*; D011109:Polymethacrylic Acids / Q000138:chemical synthesis*; D012995:Solubility; D013607:Tablets; D014783:Viscosity
chemical_list: D000959:Antihypertensive Agents; D003692:Delayed-Action Preparations; D011109:Polymethacrylic Acids; D013607:Tablets; C038300:methylmethacrylate-methacrylic acid copolymer; D065347:Hypromellose Derivatives; D008790:Metoprolol