title: Analysis of the enhanced stability of r(+)-alpha lipoic Acid by the complex formation with cyclodextrins.
abstract: R(+)-alpha lipoic acid (RALA) is one of the cofactors for mitochondrial enzymes and, therefore, plays a central role in energy metabolism. RALA is unstable when exposed to low pH or heat, and therefore, it is difficult to use enantiopure RALA as a pharma- and nutra-ceutical. In this study, we have aimed to stabilize RALA through complex formation with cyclodextrins (CDs). α-CD, β-CD and γ-CD were used for the formation of these RALA-CD complexes. We confirmed the complex formation using differential scanning calorimetry and showed by using HPLC analysis that complexed RALA is more stable than free RALA when subjected to humidity and high temperature or acidic pH conditions. Scanning electron microscopy studies showed that the particle size and shape differed depending on the cyclodextrin used for complexation. Further, the complexes of CD and RALA showed a different particle size distribution pattern compared with that of CD itself or that of the physical mixture of RALA and CD.
authors: School of Natural Systems, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan. s-matsugoh@se.kanazawa-u.ac.jp.
authors: Naoko
authors: N
authors: Ikuta
authors: Hironori
authors: H
authors: Sugiyama
authors: Hiroshi
authors: H
authors: Shimosegawa
authors: Rie
authors: R
authors: Nakane
authors: Yoshiyuki
authors: Y
authors: Ishida
authors: Yukiko
authors: Y
authors: Uekaji
authors: Daisuke
authors: D
authors: Nakata
authors: Kathrin
authors: K
authors: Pallauf
authors: Gerald
authors: G
authors: Rimbach
authors: Keiji
authors: K
authors: Terao
authors: Seiichi
authors: S
authors: Matsugo