Čes. slov. farm. 2008, 57(6):260-264
Studies of local anesthetics Part 185: Thermodynamic parameters of heptacainium chloride in the solution of NaBr
- Univerzita Komenského Bratislava, Farmaceutická fakulta, Katedra farmaceutickej chémie
The critical micellar concentration (CMC) of the local anaesthetic agent heptacainium chloride in the solution of NaBr was determined by the spectrophotometric method in the UV region of the spectrum at the temperature range of t = 20-40 °C and pH ≈ 4.5-5.0. The dependence of CMC on the temperature T formed a U-shaped curve with the minimum at the temperature of t = 25 °C. The CMC dependence on the temperature T was fitted by the second degree polynomical function. The obtained parabolic equations were applied to the "phase separation model" and the following thermodynamic parameters could be calculated: standard Gibbs free energy (∆G°), enthalpy (∆H°) and entropy (∆S°).
Keywords: heptacainium chloride; critical micellar concentration (CMC); thermodynamics; standard Gibbs free energy; enthalpy; entropy
Grants and funding:
Táto práca vznikla a je zahrnutá a do projektu VEGA č. 1/4291/07.
Received: September 2, 2008; Accepted: October 7, 2008; Published: June 1, 2008 Show citation
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