Inclusion of α-lipoic acid in β-cyclodextrin. Physical–chemical and structural characterization

Rácz, Csaba-Pal; Santa, Szabolcs; Tomoaia-Cotişel, Maria; Borodi, Gheorghe; Kacsó, Irina; Pı̂rnău, Adrian; Bratu, Ioan

doi:10.1007/s10847-012-0191-z

Cited by 27 publications

(26 citation statements)

References 17 publications

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“…Many kinds of LA-CD inclusion complexes have been reported in recent years [18,19] . Hideko Maeda, et al have previously reported a study on the LA and SBE-β-CD inclusion complex by spectroscopic and thermodynamic analysis although the improvement of solubility of LA is limited [18] .…”

Section: Inclusion Complex Of α-Lipoic Acid Containing Alkalizer For mentioning

confidence: 99%

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Inclusion Complex of alpha-Lipoic Acid Containing Alkalizer for Improving the Solubility and Stability Prepared by Co-grinding

Zheng¹,

Tang²,

Kong³

et al. 2017

pharmaceutical-sciences

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Zheng, et al.: Inclusion Complex of α-Lipoic Acid Containing AlkalizerThe inclusion complex was prepared by co-grinding α-lipoic acid with hydroxypropyl-β-cyclodextrin and alkalizer to enhance the solubility and stability of α-lipoic acid. Lipoic acid was chosen as a model drug because of its poor and pH-dependent aqueous solubility. Sodium carbonate and sodium bicarbonate were chosen as the pH regulators. Furthermore, the study investigated the proportion of alkalizer, hydroxypropyl-β-cyclodextrin and α-lipoic acid. Although the micronization has little effect on the solubility of the drug, the formation of amorphous form has an important effect of inclusion complexes. X-ray powder diffractometry and differential scanning calorimetry were used to assess the phase change of the drugs. The in vitro dissolution test indicates that the alkalizer plays a positive factor for the drug dissolution rate enhancement. The intermolecular interactions in the inclusion complexes were investigated using Fourier transform infrared spectroscopy. It was found that the drug frequency of the C=O band decreased or disappeared when the alkalizer was added. Thermal stability experiments showed that the inclusion complex have better stability after adding alkalizer. The solubility of α-lipoic acid can be increased 40 times when the ratio of α-lipoic acid and sodium carbonate is 1:1.2 in the ternary inclusion complex. It was evident that the inclusion compounds with alkalizer can improved the solubility and stability of α-lipoic acid significantly.

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Section: Inclusion Complex Of α-Lipoic Acid Containing Alkalizer For mentioning

confidence: 99%

“…LA was extracted with the solution (acetonitrile: deionized water=50:50) and detected by HPLC at 0.5, 2, 4, 8 and 24 h [19] .…”

Section: Stability Testmentioning

confidence: 99%

Inclusion Complex of alpha-Lipoic Acid Containing Alkalizer for Improving the Solubility and Stability Prepared by Co-grinding

Zheng¹,

Tang²,

Kong³

et al. 2017

pharmaceutical-sciences

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“…ALA has a relatively weak affinity for CDs [ 11 ], so it is difficult to accurately analyze the spectral changes using UV or FT-IR spectroscopy. Microscopic FT-IR can now be used to give an new analytical method that any other published analytical data of ALA-CD complexes [ 12 , 13 , 14 ]. ALA has one S–S bond and two C–S bonds in its 1,2-dithiolane and also has a chiral center at the C6 carbon, leading to two enantiomers, R (+)-ALA (RALA) and S (–)-ALA (SALA) ( Figure 2 ), of which RALA is the naturally occurring compound.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Studies of R(+)-α-Lipoic Acid—Cyclodextrin Complexes

Ikuta

Otsubo

Ogawa

et al. 2014

IJMS

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α-Lipoic acid (ALA) has a chiral center at the C6 position, and exists as two enantiomers, R(+)-ALA (RALA) and S(−)-ALA (SALA). RALA is naturally occurring, and is a cofactor for mitochondrial enzymes, therefore playing a major role in energy metabolism. However, RALA cannot be used for pharmaceuticals or nutraceuticals because it readily polymerizes via a 1,2-dithiolane ring-opening when exposed to light or heat. So, it is highly desired to find out the method to stabilize RALA. The purpose of this study is to provide the spectroscopic information of stabilized RALA and SALA through complexation with cyclodextrins (CDs), α-CD, β-CD and γ-CD and to examine the physical characteristics of the resultant complexes in the solid state. The RALA-CD structures were elucidated based on the micro fourier transform infrared (FT-IR) and Raman analyses. The FT-IR results showed that the C=O stretching vibration of RALA appeared at 1717 cm−1 and then shifted on formation of the RALA-CD complexes. The Raman spectra showed that the S–S and C–S stretching vibrations for RALA at 511 cm−1 (S–S), 631 cm−1 (C–S) and 675 cm−1 (C–S) drastically weakened and almost disappeared upon complexation with CDs. Several peaks indicative of O–H vibrations also shifted or changed in intensity. These results indicate that RALA and CDs form host-guest complexes by interacting with one another.

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“…This was confirmed submitting crystalline ALA and the intercalation products MgAl-ALA and ZnAl-ALA to differential scanning calorimetry analysis. In the thermogram of crystalline ALA reported in Figure 1 it is clearly visible a sharp endothermic peak at • C (∆H = −136.17 J/g) corresponding to the melting, following the degradation of the compound [44], while the peak relative to melting point disappears in the case of both intercalation products ( Figure 1). The particle size analysis ( Figure 2S) carried out on pristine HTlc-Cl and the corresponding intercalation products showed that MgAl-ALA is more polydisperse than ZnAl-ALA (span value 6.6 vs. 1.19 for MgAl-ALA and ZnAl-ALA, respectively).…”

Section: Hybrid Preparation and Characterizationmentioning

confidence: 96%

Development and Characterization of New Topical Hydrogels Based on Alpha Lipoic Acid—Hydrotalcite Hybrids

et al. 2019

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Alpha lipoic acid (ALA) is a well-known anti-aging compound. The activity of this molecule is limited by two important factors: (i) The low stability to oxidation and thermal processes and (ii) the low solubility. Particularly the latter limits ALA formulation in hydrophilic bases. The purpose of this paper is to present a new technological approach to stabilize lipoic acid in topical hydrogels for cosmetic use. With this aim, ALA was intercalated in two different lamellar anionic clays (hydrotalcites), MgAl and ZnAl, obtaining the hybrids MgAl-ALA and ZnAl-ALA. The intercalation allows to obtain a more manageable product in comparison to raw ALA. After the preliminary characterization, hydrogels containing the hybrids were prepared and characterized, also in comparison to the commercial product Tiobec® in terms of rheological properties, stability to temperature and centrifugation, release, and cytotoxicity. The obtained results highlighted that the hydrogel containing MgAl-ALA is a suitable alternative to the products currently available on the market.

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Inclusion of α-lipoic acid in β-cyclodextrin. Physical–chemical and structural characterization

Cited by 27 publications

References 17 publications

Inclusion Complex of alpha-Lipoic Acid Containing Alkalizer for Improving the Solubility and Stability Prepared by Co-grinding

Inclusion Complex of alpha-Lipoic Acid Containing Alkalizer for Improving the Solubility and Stability Prepared by Co-grinding

Spectroscopic Studies of R(+)-α-Lipoic Acid—Cyclodextrin Complexes

Development and Characterization of New Topical Hydrogels Based on Alpha Lipoic Acid—Hydrotalcite Hybrids

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