Table 2.
Fourier transform infrared spectrum analysis of curcumin, curcumin-methyl-β-cyclodextrin complex (1:1), and curcumin-methyl-β-cyclodextrin complex, hydroxypropyl methylcellulose physical mixture (1:1).
| Functional group | Bond vibrations | Absorption range (cm −1 ) | Observed peaks (cm −1 ) |
|---|---|---|---|
| Curcumin | |||
| Benzene ring | C-C stretching | 1450–1600 | 1557 |
| Aromatic | C=C stretching | 1500–1680 | 1623.09 |
| Ketone | C=O stretching | 1670–1750 | 1742.31 |
| Aromatic | C-H stretching | 2920–3079 | 2927.16 |
| Phenolic O-H | O-H stretching | 3200–3500 | 3282.26 and 3222.25 |
| Aromatic | C-O stretching | 1000–1300 | 1268.25 |
| Olefin | C-H bending | 1400–1500 | 1428.29 |
| Methoxy | O-CH3 bending | 1050–1100 | 1147.31 |
| Methyl- β -cyclodextrin | |||
| Hydroxyl-OH | O-H stretching | 3200–3550 | 3400 |
| Alkane | C-H stretching | 2850–2960 | 2920, 2850 |
| Carbonyl | C=O stretching | 1700–1748 | 1742.31 |
| Ether | C-O stretching | 1050–1150 | 1080 |
| HPMC | |||
| Hydroxyl-OH | O-H stretching | 3200–3550 | 3440 |
| Alkane | C-H stretching | 2850–2960 | 2930 |
| Ether | C-O stretching | 1050–1150 | 1100 |
| Methyl | C-H Bend | 1375–1450 | 1380 |