Chemical and Pharmaceutical Bulletin
Online ISSN : 1347-5223
Print ISSN : 0009-2363
Release Kinetics of Nicotinamide from Fatty Acid-Nicotinamide Equipmolar Complexes. II. Activation Thermodynamic Quantities
Shoko YOKOYAMAFumio UEDATadao FUJIE
Author information
JOURNALS FREE ACCESS

Volume 39 (1991) Issue 12 Pages 3114-3119

Details
Download PDF (728K) Contact us
Abstract

The rates of release of nicotinamide (NAA) from fatty acid (FA)-NAA complexes, FA-NAA, were determined at various temperatures, and the thermodynamic quantities for the release of NAA were estimated. The results were compared with the previous results obtained for FA-thiamine disulfide (TDS) complexes, (FA)6(TDS). The values of activation enthalpy (ΔH) and activation entropy (ΔS) for the releaes of NAA from FA-NAA were positive and negative, respectively, indicating that the release of NAA is disadvantageous from not only enthalpic but aso entropic viewpoints. The plots of ΔH against the carbon number (n) in the constituent FA showed a zig-zag line wiht an upward convex at an odd-numbered position and teh polts of the absolute values of ∣-Δ∣ showed a zig-zag line wiht a downward convex at an odd-numbered position, through the positive values ΔH increases and the negative value of ΔS decreases with an increasing n for either even-numbered or odd-numbered FA. It was found that the release of NAA from FA-NAA formed with odd-numbered FA is more disadvantageous enthelpically but more advantageous entropically as compared with that from FA-NAA formed with even-numbered FA. THis phenomenon was simillar to that observed for (FA)6(TDS). Furthermore, it is suggested that FA-NAA is formed at least by van der Waals forces and hydrophobic interactions and that van der Waals forces are dominant for the formation of FA-NAA formed with odd-numbered FA and that hydrophobic interactions are dominant for the formation of FA-NAA formed with even-numberes FA.

Information related to the author
© The Pharmaceutical Society of Japan
Previous article Next article
feedback
Top