title: Development and in vitro evaluation of floating rosiglitazone maleate microspheres.
abstract: BACKGROUND
  Various approaches have been used to retain the dosage form in stomach as a way of increasing the gastric residence time, including floatation systems; high-density systems; mucoadhesive systems; magnetic systems; unfoldable, extensible, or swellable systems; and superporous hydrogel systems.
  
  
  OBJECTIVE
  The objective of this study was to prepare and evaluate floating microspheres of rosiglitazone maleate for the prolongation of gastric residence time.
  
  
  METHODS
  The microspheres were prepared by solvent diffusion-evaporation method using ethyl cellulose and hydroxypropylmethylcellulose. A full factorial design was applied to optimize the formulation.
  
  
  RESULTS
  Preliminary studies revealed that the polymer:drug ratio, concentration of polymer, and stirring speed significantly affected the characteristics of microspheres. The optimum batch exhibited a prolonged drug release, remained buoyant for >12 hours, high entrapment efficiency, and particle size in the order of 350 microm.
  
  
  CONCLUSIONS
  The results of 32 full factorial design revealed that the concentration of ethylcellulose 7 cps (X(1)) and stirring speed (X(2)) significantly affected drug entrapment efficiency, percentage release after 8 h and particle size of microspheres.
authors.affiliation: AISSMS College of Pharmacy, Kennedy Road, Pune, India. monicarp_6@hotmail.com.
authors.forename: M R P
authors.initials: MR
authors.lastname: Rao
authors.forename: S G
authors.initials: SG
authors.lastname: Borate
authors.forename: K C
authors.initials: KC
authors.lastname: Thanki
authors.forename: A A
authors.initials: AA
authors.lastname: Ranpise
authors.forename: G N
authors.initials: GN
authors.lastname: Parikh