Dextrin Nanocomposites as Matrices for Solid Dosage Forms

Justin Phillips, Jaco Louis Venter, Maria Atanasova, James Wesley-Smith, Hester Oosthuizen, M. Naushad Emmambux, Elizabeth L. Du Toit*, Walter W. Focke

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Safe application of water-insoluble acaricides requires fast release from solid dosage systems into aquatic environments. Dextrin is a water-soluble form of partially hydrolyzed starch, which may be used as matrix material for these systems if retrogradation can be inhibited by the inclusion of nanofillers. Several glycerol-plasticized thermoplastic dextrin-based nanocomposites were prepared with a twin-screw extrusion-compounding process. The nanofillers included a layered double hydroxide (LDH), cellulose nanofibers (CNF), and stearic acid. The time-dependent retrogradation of the compounds was monitored by X-ray diffraction (XRD) and dynamic mechanical thermal analysis (DMA). XRD showed that composite samples that included stearic acid in the formulation led to the formation of an amylose-lipid complex and a stable crystallinity during aging. The most promising nanocomposite included both stearic acid and CNF. It was selected as the carrier material for the water-insoluble acaricide Amitraz. Fast release rates were observed for composites containing 5, 10, and 20% (w/w) of the pesticide. A significant reduction in the particle size of the released Amitraz powder was observed, which is ascribed to the high-temperature compounding procedure.

Original languageEnglish
Pages (from-to)16969-16977
Number of pages9
JournalACS Applied Materials and Interfaces
Issue number14
Publication statusPublished - 8 Apr 2020
Externally publishedYes


  • acaricide, themoplastic starch
  • cellulose nanofibers
  • dextrin
  • layered double hydroxide, solid dosage form


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