title: Microwave-induced solid dispersion technology to improve bioavailability of glipizide.
abstract: OBJECTIVE
  The effect of microwave (MW) irradiation and conventional heating (CH) on solid dispersion (SD) of poorly water-soluble glipizide (GPZ) and polyethylene glycol 4000 (PEG 4000) were studied in detail.
  
  
  METHODS
  The chemical stability of GPZ on exposure to MW irradiation and CH was confirmed by high-performance liquid chromatography, Fourier transform infra red spectroscopy, proton nuclear magnetic resonance and mass spectroscopy studies. Comparative bioavailability studies were performed in rabbits using glipizide sustained-release tablets prepared using MW irradiation (MW-SD) or CH (CH-SD), with Glytop 2.5 mg SR as a reference.
  
  
  RESULTS
  The MW-assisted melt mixing showed higher efficiency than CH in obtaining a homogeneous mixture having glass transparency. The polymorphic transformation of GPZ in each case was further confirmed by powder X-ray diffraction study. The solubility of GPZ in phosphate buffer pH 6.8 was greater for MW-SD (72.250 ± 0.154 μg/ml) than CH-SD (46 ± 0.201 μg/ml). The MW-SD matrix tablet (2.5 mg) displayed retarded drug release (releasing 99.320 ± 4.992% drug in 12 h). In-vivo pharmacokinetic study in rabbits revealed that the relative bioavailability of GPZ from MW-SD tablets improved greatly (153.73 ± 9.713%).
  
  
  CONCLUSIONS
  MW-induced SD technology could be a better alternative to CH-SD for the enhanced solubility and bioavailability of GPZ.
authors.affiliation: Department of Pharmaceutical Sciences, Birla Institute of Technology, Ranchi, India.
authors.forename: Jinu
authors.initials: J
authors.lastname: Isaac
authors.forename: Santanu
authors.initials: S
authors.lastname: Kaity
authors.forename: Swastika
authors.initials: S
authors.lastname: Ganguly
authors.forename: Animesh
authors.initials: A
authors.lastname: Ghosh
mesh_terms: D000818:Animals; D001682:Biological Availability; D003692:Delayed-Action Preparations; D004355:Drug Stability; D005898:Glass / Q000737:chemistry; D005913:Glipizide / Q000737:chemistry* / Q000493:pharmacokinetics*; D006361:Heating / Q000379:methods; D006863:Hydrogen-Ion Concentration; D008872:Microwaves; D011092:Polyethylene Glycols / Q000737:chemistry; D011817:Rabbits; D012995:Solubility; D013607:Tablets / Q000737:chemistry* / Q000493:pharmacokinetics; D013678:Technology, Pharmaceutical / Q000379:methods*; D014867:Water / Q000737:chemistry
chemical_list: D003692:Delayed-Action Preparations; D013607:Tablets; D014867:Water; D011092:Polyethylene Glycols; D005913:Glipizide