title: Preparation and characterization and release properties of Eudragit RS based ibuprofen pellets prepared by extrusion spheronization: effect of binder type and concentration.
abstract: OBJECTIVE
  The effects of type and concentration of binding agent on properties of Eudragit RS based pellets were studied.
  
  
  METHODS
  Pellets containing ibuprofen (60%), Eudragit RS (30%), Avicel (10%) were prepared by extrusion spheronization. PVP K30, PVP K90, HPMC 6cp, HPMC K100LV or HPMC K4M were used as binders in concentrations of 2, 4 or 6% based on the total weight of formulation. The process efficiency, pellet shape, size distribution, crushing strength, elastic modulus and drug release were examined. The effect of curing on pellet properties was also investigated.
  
  
  RESULTS
  The process of extrusion spheronization became difficult with increase in binder viscosity and/or concentration. An increase in binder viscosity and/or concentration resulted in reduction in the yield of pellets, wider particle size distribution and departure from spherical shape especially in the case of HPMC binder. The crushing strength and elastic modulus of pellets decreased with increase in PVPs concentration. However this was not the case for pellets containing HPMCs. Drug release rate increased as the concentration of binder increased. Pellets containing 2%w/w of PVP K30 showed the slowest release rate. For those pellets with brittle nature, curing changed the behavior of pellet under mechanical test to plastic deformation. Yield point and elastic modulus of all formulations decreased after curing. Curing decreased the drug release rate.
  
  
  CONCLUSIONS
  Binder type and concentration significantly affected the properties of pellets. For production of sustained release ibuprofen Eudragit RS based pellets lower viscosity binders (PVP K30) with concentrations less than 4%w/w was optimum.
authors.affiliation: Pharmaceutical Research center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Hadi Afrasiabi
authors.initials: HA
authors.lastname: Garekani
authors.forename: Ali
authors.initials: A
authors.lastname: Nokhodchi
authors.forename: Mohammad Amirpour
authors.initials: MA
authors.lastname: Rayeni
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Sadeghi
mesh_terms: D000180:Acrylic Resins / Q000008:administration & dosage* / Q000737:chemistry; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage*; D001696:Biomechanical Phenomena; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D065347:Hypromellose Derivatives; D007052:Ibuprofen / Q000008:administration & dosage* / Q000737:chemistry; D008747:Methylcellulose / Q000008:administration & dosage / Q000031:analogs & derivatives; D008970:Molecular Weight; D011205:Povidone / Q000008:administration & dosage; D012995:Solubility
chemical_list: D000180:Acrylic Resins; D000894:Anti-Inflammatory Agents, Non-Steroidal; D003692:Delayed-Action Preparations; C050528:Eudragit RS; D065347:Hypromellose Derivatives; D008747:Methylcellulose; D011205:Povidone; D007052:Ibuprofen