Study of the recrystallization in coated pellets - Effect of coating on API crystallinity

Krisztina Nikowitz, Klára Pintye-Hódi, Géza Regdon

Research output: Contribution to journalArticle

14 Citations (Scopus)


Coated diltiazem hydrochloride-containing pellets were prepared using the solution layering technique. Unusual thermal behavior was detected with differential scanning calorimetry (DSC) and its source was determined using thermogravimetry (TG), X-ray powder diffraction (XRPD) and hot-stage microscopy. The coated pellets contained diltiazem hydrochloride both in crystalline and amorphous form. Crystallization occurs on heat treatment causing an exothermic peak on the DSC curves that only appears in pellets containing both diltiazem hydrochloride and the coating. Results indicate that the amorphous fraction is situated in the coating layer. The migration of drugs into the coating layer can cause changes in its degree of crystallinity. Polymeric coating materials should therefore be investigated as possible crystallization inhibitors.

Original languageEnglish
Pages (from-to)563-571
Number of pages9
JournalEuropean Journal of Pharmaceutical Sciences
Issue number3
Publication statusPublished - Feb 14 2013


  • Coating
  • Diltiazem hydrochloride
  • Pellet
  • Recrystallization

ASJC Scopus subject areas

  • Pharmaceutical Science

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