Related Experiment Video
Updated: Jul 3, 2026

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by π-π Stacking Interactions
Published on: October 10, 2016
[Studies on local anesthetics. Part 183: micellization and thermodynamic parameters of heptacainium chloride in the
F Andriamainty1, J Cizmárik, I Malík
1Univerzita Komenského Bratislava, Farmaceutická fakulta, Katedra farmaceutickej chémie. mouanda@fpharm.uniba.sk
Abstract:
The critical micellar concentration (CMC) of the local anaesthetic agent heptacainium chloride in the solution of KBr was determined by the spectrophotometric method in the UV region of the spectrum at the temperature range of t = 20-40 degrees C and pH = 4.5-5.0. The dependence of CMC on the temperature T turned out forming the U-shape with the minimum at the temperature of t = 25 degrees C. The parabolic dependence of CMC on the temperature T was drawn by the fitting of the values using the polynomial function and the so-called power law equation. The CMC dependence on the temperature T was fitted by the second degree polynomial function. The obtained parabolic equations were applied to the "phase separation model", so the following thermodynamic parameters could be calculated: standard Gibbs free energy (deltaG), enthalpy (deltaH degrees), and entropy (deltaS degrees). The thermodynamic parameters were further used to determine the so-called entropy-enthalpy compensation of the systems under study. The compensation temperature was in the following range: (301 +/- 1-303 +/- 3)K. Then the temperature dependence of the enthalpy (deltaH degrees) and entropy (-TdeltaS degrees) contributions to the standard Gibbs free energy (deltaG degrees) for all prepared concentrations of the compound were calculated.
Related Concept Videos
Local Anesthetics: Chemistry and Structure-Activity Relationship
Local Anesthetics: Mechanism of Action
Local anesthetics are amphiphilic molecules consisting of a hydrophobic aromatic part linked to a hydrophilic group by an ester or amide linkage. They are weak bases and are usually available as salts, which increases their solubility and stability. Once administered, LAs exist in the body either...
Local Anesthetics: Pharmacokinetics
Alkyl Halides
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
Local Anesthetics: Clinical Application as Intravenous Regional Anesthesia
One of the advantages of...
Local Anesthetics: Clinical Application as Spinal Anesthesia

