Intermolecular Dynamics and Structure in Aqueous Lidocaine Hydrochloride Solutions
Hideaki Shirota1, Keiichi Yanase2, Taiki Ogura2
1Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan.
The Journal of Physical Chemistry. B
|February 16, 2022
Summary
Aqueous solutions of lidocaine hydrochloride (LDHCl) show micelle-like aggregation. Spectroscopic and scattering methods reveal nanometer-sized structures forming above 1 M concentration.
Area of Science:
- Physical Chemistry
- Materials Science
- Biophysics
Background:
- Lidocaine hydrochloride (LDHCl) is a widely used local anesthetic.
- Understanding its behavior in aqueous solutions is crucial for pharmaceutical applications.
- Intermolecular interactions and aggregation phenomena influence drug efficacy and delivery.
Purpose of the Study:
- To investigate the intermolecular dynamics and static structure of aqueous LDHCl solutions.
- To characterize the concentration-dependent aggregation behavior of LDHCl.
- To elucidate the formation of micelle-like structures in LDHCl solutions.
Main Methods:
- Femtosecond Raman-induced Kerr effect spectroscopy (fs-RIKES) for intermolecular vibrations.
- Small- and wide-angle X-ray scattering (SWAXS) for structural analysis.
- Dynamic light scattering (DLS) for aggregate size determination.
Main Results:
- fs-RIKES showed concentration-dependent intermolecular vibrations with a characteristic concentration of ~1 M.
- SWAXS revealed excess scattering indicative of nanometer-sized micelle-like structures (~0.3 nm core, ~0.5 nm shell).
- DLS confirmed nanometer-sized aggregates and clusters, supported by viscosity, density, and surface tension measurements.
Conclusions:
- LDHCl forms unique micelle-like nanostructures in aqueous solutions.
- Aggregation is concentration-dependent, initiating around 1 M.
- These findings provide insights into LDHCl's solution behavior and potential for drug delivery systems.
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