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Characteristics of amorphous complex formed between indomethacin and lidocaine hydrochloride

Yohsuke Shimada1, Satoru Goto, Hiromi Uchiro

  • 1Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda, Chiba, Japan.

Colloids and Surfaces. B, Biointerfaces
|January 29, 2013
PubMed

Insights

Indomethacin forms amorphous complexes with lidocaine hydrochloride (LH) via heat treatment, resulting in a homogenous amorphous state (IM/LH). This interaction differs from that with lidocaine, impacting amorphous solid dispersion formation.

Area of Science:

  • Pharmaceutical Sciences
  • Materials Science
  • Physical Chemistry

Background:

  • Indomethacin (IM) readily forms amorphous complexes with lidocaine (LC) upon heating.
  • Understanding the mechanism of amorphous complex formation is crucial for drug formulation.

Purpose of the Study:

  • To investigate the mechanism of amorphous complex formation between indomethacin (IM) and lidocaine hydrochloride (LH).
  • To analyze temperature-dependent phase changes and structural interactions in IM-LH mixtures.

Main Methods:

  • Differential Scanning Calorimetry (DSC) to study thermal properties and phase transitions.
  • Nuclear Magnetic Resonance (NMR) spectroscopy to probe molecular interactions and electronic structures.

Main Results:

  • Heating IM and LC mixtures formed a eutectic mixture.
  • Heating IM and LH mixtures resulted in IM dissolving into fused LH, forming a homogenous amorphous state (IM/LH) upon cooling, exhibiting glass transition.
  • NMR studies indicated IM alters LH's electronic structure, but to a lesser extent than with LC.
  • The interaction mode of LH with IM differs from that of LC with IM.

Conclusions:

  • Indomethacin and lidocaine hydrochloride form a distinct amorphous solid state (IM/LH) with unique thermal properties.
  • The interaction between indomethacin and lidocaine hydrochloride is mechanistically different from that with lidocaine.
  • These findings provide insights into amorphous complex formation and drug-solubility enhancement strategies.

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