Improved efficacy of appetite suppression by lipoic acid particles prepared by nanocomminution

Abstract

Purpose: This article was intended to improve the efficacy of alpha-lipoic acid (ALA) for appetite suppression by controlling the particle size and self-polymerization of ALA. Methods: ALA was fabricated into micro- and nanoparticles, and the efficacy and in vitro release were investigated. Because of the self-polymerization of ALA into poly[3-(n-butane carboxylic acid)propyl]disulfide (PBCPD) by processing heat, low-speed rotation comminution was used to control PBCPD content. Results: The ALA particle size initially decreased and then increased after 10 hours of nanocomminution, indicating aggregation related to PBCPD formation. The in vitro release of ALA was significantly reduced by the existence of PBCPD. Interestingly, the reduction was not followed by a decrease in efficacy. Alternatively, the food intake was significantly reduced by ALA particles containing more than 30 mol% PBCPD. Conclusions: When the particle size and self-polymerization of ALA were carefully controlled, the efficacy on appetite suppression could be superior to water-soluble ALA salt. The ALA particles might have a composite nanostructure of ALA and PBCPD.