Characterisation of freeze-dried wafers and solvent evaporated films as potential drug delivery systems to mucosal surfaces

J.S. Boateng, A.D. Aufrett, K.H. Matthews, M.J. Humphry, H.N.E. Stevens, G.M. Eccleston

Research output: Contribution to journalArticle

78 Citations (Scopus)

Abstract

Freeze-dried (lyophilised) wafers and solvent cast films from sodium alginate (ALG) and sodium carboxymethylcellulose (CMC) have been developed as potential drug delivery systems for mucosal surfaces including wounds. The wafers (ALG, CMC) and films (CMC) were prepared by freeze-drying and drying in air (solvent evaporation) respectively, aqueous gels of the polymers containing paracetamol as a model drug. Microscopic architecture was examined using scanning electron microscopy, hydration characteristics with confocal laser scanning microscopy and dynamic vapour sorption. Texture analysis
was employed to investigate mechanical characteristics of the wafers during compression. Differential scanning calorimetry was used to investigate polymorphic changes of paracetamol occurring during formulation of the wafers and films. The porous freeze-dried wafers exhibited higher drug loading and water absorption capacity than the corresponding solvent evaporated films. Moisture absorption, ease of hydration and mechanical behaviour were affected by the polymer and drug concentration. Two polymorphs of paracetamol were observed in the wafers and films, due to partial conversion of the original monoclinic to the orthorhombic polymorph during the formulation process. The results showed the potential of employing the freeze-dried wafers and solvent evaporated films in diverse mucosal applications due to their ease of hydration and based on different physical mechanical properties exhibited by both type of formulations.
Original languageEnglish
Pages (from-to)24-31
Number of pages8
JournalInternational Journal of Pharmaceutics
Volume389
Issue number1-2
DOIs
Publication statusPublished - 15 Apr 2010

Keywords

  • carboxymethyl cellulose
  • sodium alginate
  • solvent evaporated films
  • physical properties
  • freeze-dried wafers

Cite this