Comparative isoconversional thermal analysis of Artemisia vulgaris hydrogel and its acetates; a potential matrix for sustained drug delivery

Abstract

Artemisia vulgaris hydrogel (AVH) was acetylated (AAVH) and characterized by FTIR, CP/MAS ¹³C-NMR spectroscopic techniques and thermogravimetric analysis. Flynn–Waal–Ozawa model was used to investigate thermal degradation kinetics. Energy of activation (Ea) values of first and major thermal degradation steps were found to be 128.14 and 116.85 kJmol⁻¹ for AVH and AAVH, respectively. Thermodynamic triplet, order of degradation reaction, integral procedural decomposition temperature (IPDT) and comprehensive index of intrinsic thermal stability (ITS) were also taken into account. In vitro caffeine release from AVH-based matrix tablets indicates potential of AVH for the development of oral delivery systems for sustained drug release.

Keywords:

• Artemisia vulgaris hydrogel
• isoconversional thermal analysis
• acetylation
• drug release
• solid-state NMR

Acknowledgment

Hatem M.A. Amin acknowledges Nick Rees, Oxford University, for collecting some of the NMR data.

Disclosure statement

No potential conflict of interest was reported by the author(s).