Safety Evaluation of R(+)-Alpha Lipoic Acid-Gamma Cyclodextrin Complex

R(+)-alpha lipoic acid (RALA) is one of cofactors for mitochondrial enzymes and therefore plays a central role in energy metabolism. RALA is unstable when exposed to low pH or heat. Therefore, we have stabilized RALA through complex formation with cyclodextrins (γ-CDs). γ-CDs were used for the formation of these RALA-CD complexes. In this study, we evaluated the safety of RALA-CD complex through in vitro and in vivo toxicity tests as follows: an acute toxicity study, the Ames test, and a subchronic toxicity study using thiamine-deficient rats. These toxicity studies showed that RALA-CD produced no toxic effects, and support the safety of oral supplementation of RALA-CD. Further, RALA-CD administration showed a different effect on food intake and body weight of thiamine-deficient rats when compared with the complexes of CD and SALA and DL-ALA.