title: Formulation development and evaluation of metformin chewing gum with bitter taste masking.
abstract: BACKGROUND
  Medicated gums are intended to be chewed and act either locally, absorbed via the buccal mucosa or swallowed with saliva. We prepared the metformin gum to overcome its side effects including vomiting, diarrhea, and abdomen discomfort. Furthermore, it could be useful for those who have swallowing problems.
  
  
  METHODS
  Metformin hydrochloride (250 mg) with suitable sweeteners was mixed manually for 5 min. This mixture was spray dried, freeze dried, or directly mixed with chewing gum base. Glycerin, xylitol, and menthol were added and the produced paste was kept in the freezer for 2 h to be stable. As the metformin shows bitter taste, we tried to mask this unpleasant taste with using different methods explained. The releasing pattern was evaluated by using a mechanical chewing machine. The best formulation with the optimized releasing pattern, suitable physicochemical properties and pleasant taste were selected. Content uniformity, releasing percent, and other physicochemical properties were identified as well. Taste, flavor, and appearance characteristics were evaluated by using a self-made questionnaire based on the hedonic test method.
  
  
  RESULTS
  The chewing gum dosage content was about 86.2%. The release rate of metformin chewing gum was about 70% after 5 min of mastication. Masking the bitter taste of drug was achieved by using acesulfame-isomalt as sweeteners and prepared it by freeze drying equipment.
  
  
  CONCLUSIONS
  Metfornin chewing gum had suitable appearance and appropriate invitro characteristics that fallow the pharmacopeia suggestions. This chewable gum showed bitterness suppression with a suitable release rate.
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences and Isfahan Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Sayed Abolfazl
authors.initials: SA
authors.lastname: Mostafavi
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences and Isfahan Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Jaleh
authors.initials: J
authors.lastname: Varshosaz
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences and Isfahan Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Saber
authors.initials: S
authors.lastname: Arabian
keywords: Acesulfame-isomalt; freeze drying; hedonic test; medicated chewing gum; metformin