title: Floating microspheres of carvedilol as gastro retentive drug delivery system: 3(2) full factorial design and in vitro evaluation.
abstract: BACKGROUND
  Designing a sustained release system for Carvedilol to increase its residence time in the stomach.
  
  
  OBJECTIVE
  Preparation of floating microsphere by the emulsion solvent diffusion method, studying the effect of various process parameters and optimize the formulation using full factorial design.
  
  
  METHODS
  Different microsphere formulations were prepared by varying the ratio ethanol:dichloromethane (1:0 to 1:1.5), ethyl cellulose:hydroxypropyl methyl cellulose and stirring speed (800-1600 rpm). The effect of these variables on particle size, encapsulation parameters, surface topography, in vitro floatability and drug release were evaluated.
  
  
  RESULTS
  3(2) full factorial design was used for the optimization of the formulation. Drug entrapment efficiency, particle size and in vitro drug release were dependent on concentration of ethyl cellulose and stirring speed. Microspheres remained buoyant for more than 10 h and showed sustained release of the drug.
  
  
  CONCLUSIONS
  Floating microspheres of Carvedilol with good floating ability and sustained release were developed.
authors.affiliation: University College of Pharmacy, Mahatma Gandhi University, Ettumanoor , Kerala , India .
authors.forename: M V
authors.initials: MV
authors.lastname: Nila
authors.forename: M R
authors.initials: MR
authors.lastname: Sudhir
authors.forename: T A
authors.initials: TA
authors.lastname: Cinu
authors.forename: N A
authors.initials: NA
authors.lastname: Aleykutty
authors.forename: S
authors.initials: S
authors.lastname: Jose
mesh_terms: D002227:Carbazoles / Q000008:administration & dosage / Q000737:chemistry* / Q000378:metabolism*; D000077261:Carvedilol; D002626:Chemistry, Pharmaceutical; D016503:Drug Delivery Systems / Q000379:methods*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism; D008863:Microspheres; D010316:Particle Size; D011412:Propanolamines / Q000008:administration & dosage / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol