Characterization and Evaluation of Ternary Complexes of Ascorbic Acid with γ-Cyclodextrin and Poly(vinyl Alcohol)
Ascorbic acid (AA) is a general antioxidant used in aqueous pharmaceutical formulations. However, in aqueous solutions, AA is unstable and easily oxidized when exposed to air, light and/or heat. Cyclodextrins are well known for their ability to form inclusion complexes with various compounds to impr...
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| Format: | Article |
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MDPI AG
2020-06-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/21/12/4399 |
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| author | Phennapha Saokham Kanokporn Burapapadh Pitsiree Praphanwittaya Thorsteinn Loftsson |
| author_facet | Phennapha Saokham Kanokporn Burapapadh Pitsiree Praphanwittaya Thorsteinn Loftsson |
| author_sort | Phennapha Saokham |
| collection | DOAJ |
| description | Ascorbic acid (AA) is a general antioxidant used in aqueous pharmaceutical formulations. However, in aqueous solutions, AA is unstable and easily oxidized when exposed to air, light and/or heat. Cyclodextrins are well known for their ability to form inclusion complexes with various compounds to improve their solubility and stability. Previous studies demonstrate that cyclodextrins preserve the antioxidant capacity of AA but data for γ-cyclodextrin (γCD) have not been reported. Poly(vinyl alcohol) (PVA) is a hydrophilic polymer widely used as a drug matrix in various pharmaceutical fields, but its application for drug stabilization is limited. This study aimed to investigate the protective ability of γCD on AA through the formation of ternary complexes with PVA. Binary (i.e., AA/γCD, AA/PVA and γCD/PVA) and ternary (i.e., AA/γCD/PVA) complexes were first confirmed. It was reported that those complexes were formed through interactions between the heterocyclic ring of AA, hydroxyl group of PVA and hydrophobic cavity of γCD. The hydrodynamic diameter of complexes was then studied. It was found that the diameter of γCD/PVA complexes increased with respect to the concentration of γCD. Higher γCD concentrations also resulted in increasing hydrodynamic diameters of the ternary complex. The presence of AA in ternary complexes interfered with the aggregation tendency of γCD/PVA binary complexes. Furthermore, the antioxidant capacity of AA in binary and ternary complexes was investigated. It was found that the presence of γCD preserved the antioxidant activity of AA, whereas PVA showed a contrasting effect. The influence of γCD and PVA concentration on antioxidant capacity was then studied through central composite design (CCD). Even though the concentration of γCD significantly affected the inhibition efficiency of the ternary complex, the insignificant influence of PVA could not be ignored. A promising protective ternary complex should consist of an optimized concentration of PVA and a high concentration of γCD. |
| first_indexed | 2024-03-10T19:00:42Z |
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| language | English |
| last_indexed | 2024-03-10T19:00:42Z |
| publishDate | 2020-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-e40e3d74794c4872a0afa2753d4df6732023-11-20T04:28:46ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672020-06-012112439910.3390/ijms21124399Characterization and Evaluation of Ternary Complexes of Ascorbic Acid with γ-Cyclodextrin and Poly(vinyl Alcohol)Phennapha Saokham0Kanokporn Burapapadh1Pitsiree Praphanwittaya2Thorsteinn Loftsson3Department of Manufacturing Pharmacy, College of Pharmacy, Rangsit University, Pathum Thani 12000, ThailandDepartment of Manufacturing Pharmacy, College of Pharmacy, Rangsit University, Pathum Thani 12000, ThailandFaculty of Pharmaceutical Sciences, University of Iceland, Hofsvallagata 53, IS-107 Reykjavik, IcelandFaculty of Pharmaceutical Sciences, University of Iceland, Hofsvallagata 53, IS-107 Reykjavik, IcelandAscorbic acid (AA) is a general antioxidant used in aqueous pharmaceutical formulations. However, in aqueous solutions, AA is unstable and easily oxidized when exposed to air, light and/or heat. Cyclodextrins are well known for their ability to form inclusion complexes with various compounds to improve their solubility and stability. Previous studies demonstrate that cyclodextrins preserve the antioxidant capacity of AA but data for γ-cyclodextrin (γCD) have not been reported. Poly(vinyl alcohol) (PVA) is a hydrophilic polymer widely used as a drug matrix in various pharmaceutical fields, but its application for drug stabilization is limited. This study aimed to investigate the protective ability of γCD on AA through the formation of ternary complexes with PVA. Binary (i.e., AA/γCD, AA/PVA and γCD/PVA) and ternary (i.e., AA/γCD/PVA) complexes were first confirmed. It was reported that those complexes were formed through interactions between the heterocyclic ring of AA, hydroxyl group of PVA and hydrophobic cavity of γCD. The hydrodynamic diameter of complexes was then studied. It was found that the diameter of γCD/PVA complexes increased with respect to the concentration of γCD. Higher γCD concentrations also resulted in increasing hydrodynamic diameters of the ternary complex. The presence of AA in ternary complexes interfered with the aggregation tendency of γCD/PVA binary complexes. Furthermore, the antioxidant capacity of AA in binary and ternary complexes was investigated. It was found that the presence of γCD preserved the antioxidant activity of AA, whereas PVA showed a contrasting effect. The influence of γCD and PVA concentration on antioxidant capacity was then studied through central composite design (CCD). Even though the concentration of γCD significantly affected the inhibition efficiency of the ternary complex, the insignificant influence of PVA could not be ignored. A promising protective ternary complex should consist of an optimized concentration of PVA and a high concentration of γCD.https://www.mdpi.com/1422-0067/21/12/4399γ-cyclodextrinpoly(vinyl alcohol)ascorbic acidinclusion complexantioxidant activity |
| spellingShingle | Phennapha Saokham Kanokporn Burapapadh Pitsiree Praphanwittaya Thorsteinn Loftsson Characterization and Evaluation of Ternary Complexes of Ascorbic Acid with γ-Cyclodextrin and Poly(vinyl Alcohol) International Journal of Molecular Sciences γ-cyclodextrin poly(vinyl alcohol) ascorbic acid inclusion complex antioxidant activity |
| title | Characterization and Evaluation of Ternary Complexes of Ascorbic Acid with γ-Cyclodextrin and Poly(vinyl Alcohol) |
| title_full | Characterization and Evaluation of Ternary Complexes of Ascorbic Acid with γ-Cyclodextrin and Poly(vinyl Alcohol) |
| title_fullStr | Characterization and Evaluation of Ternary Complexes of Ascorbic Acid with γ-Cyclodextrin and Poly(vinyl Alcohol) |
| title_full_unstemmed | Characterization and Evaluation of Ternary Complexes of Ascorbic Acid with γ-Cyclodextrin and Poly(vinyl Alcohol) |
| title_short | Characterization and Evaluation of Ternary Complexes of Ascorbic Acid with γ-Cyclodextrin and Poly(vinyl Alcohol) |
| title_sort | characterization and evaluation of ternary complexes of ascorbic acid with γ cyclodextrin and poly vinyl alcohol |
| topic | γ-cyclodextrin poly(vinyl alcohol) ascorbic acid inclusion complex antioxidant activity |
| url | https://www.mdpi.com/1422-0067/21/12/4399 |
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