title: Effect of solvent on retarding the release of diltiazem HCl from Polyox-based liquisolid tablets.
abstract: OBJECTIVE
  The aim of this work was to investigate the use of liquisolid technique to sustain the release of a model highly soluble drug, diltiazem HCl, from liquisolid matrices containing Polyox, a recently proposed matrix-forming hydrophilic polymer as an alternative to hypromellose.
  
  
  METHODS
  Polyox-based liquisolid formulations prepared using several non-volatile solvents (i.e. polysorbate 80, polyethylene glycol, polyethylene glycol 200 and polyethylene glycol 600) and then characterised using differential scanning calorimetry and powder X-ray diffraction. The influence of solvent on retarding the release of diltiazem HCl from Polyox-based liquisolid tablets compared to conventional physical mixture tablets was studied.
  
  
  RESULTS
  Liquisolid tablets exhibited greater retarding properties compared to conventional tablets. The use of polysorbate produced a slower release pattern of the drug from diltiazem hydrochloride (DTZ) liquisolid tablets compared to propylene glycol and polyethylene glycol (200 and 600). The release retardation was decreased with the increase in the concentration of the drug within drug:solvent liquid medication used. Solid-state analysis suggested the presence of a fraction of the drug mass in a solubilised state within polysorbate in liquisolid powders.
  
  
  CONCLUSIONS
  Polyox-based matrix tablets prepared using liquisolid technique in the presence of a carefully selected non-volatile solvent could produce desirable, more sustained release profiles of highly water-soluble drugs compared to conventional physical mixture tablets.
authors.affiliation: School of Pharmacy, Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, UK. w.kaialy@wlv.ac.uk.
authors.forename: Waseem
authors.initials: W
authors.lastname: Kaialy
authors.affiliation: School of Pharmacy, Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, UK.
authors.forename: Hussaini
authors.initials: H
authors.lastname: Bello
authors.affiliation: Department of Pharmacy, University of Huddersfield, Huddersfield, UK.
authors.forename: Kofi
authors.initials: K
authors.lastname: Asare-Addo
authors.affiliation: School of Life Sciences, University of Sussex, Falmer, Brighton, UK.|Drug Applied Research Center and Faculty of Pharmacy, Tabriz Medical Sciences University, Tabriz, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Nokhodchi
mesh_terms: D002152:Calorimetry, Differential Scanning; D018360:Crystallography, X-Ray; D003692:Delayed-Action Preparations; D004110:Diltiazem / Q000737:chemistry*; D004339:Drug Compounding; D007700:Kinetics; D011092:Polyethylene Glycols / Q000737:chemistry*; D011136:Polysorbates / Q000737:chemistry*; D033362:Powder Diffraction; D019946:Propylene Glycol / Q000737:chemistry*; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D013607:Tablets; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D003692:Delayed-Action Preparations; D011136:Polysorbates; D012997:Solvents; D013607:Tablets; D011092:Polyethylene Glycols; D019946:Propylene Glycol; D004110:Diltiazem
keywords: Polyox; diltiazem HCl; liquisolid tablets; matrix systems; polysorbate 80; sustained release