Table 5.
Interpretation of the functional group and wave number by FTIR analysis.
| Sample | Frequency (cm−1) | Interpretation | Compound class |
|---|---|---|---|
| Sildenafil citrate | 3328 | N–H stretch | |
| 1618 | N–H bend | ||
| 1585 | Carboxylic acid | (citrate) | |
| 1265 | SO2 | (symmetric) | |
| 1323 | SO2 | (asymmetric) | |
| 1094 | C-N | ||
| Microemulsion (IPM system) + poloxamer 188 | 3406 | OH | (H2O), poloxamer, PEG400 |
| 2923, 2855 | C–H alkane | ||
| 1734 | COO–R | ||
| 1102 | C–O | ||
| Microemulsion (IPM system) + poloxamer 188 + Sildenafil citrate | 3406 | OH | |
| 2923, 2855 | C–H alkane | ||
| 1734 | COO–R | ||
| 1632 | N–H bend | (sildenafil) | |
| 1589 | Carboxylic acid | (citrate) | |
| Microemulsion (OA system) + poloxamer 188 | 3378 | OH | (H2O), poloxamer, PG |
| 2924, 2855 | C–H alkane | ||
| 1712 | COOH | (oleic acid) | |
| 1647 | C=C alkene | (oleic acid) | |
| 1102 | C–O | ||
| Microemulsion (OA system) + poloxamer 188 + Sildenafil citrate | 3380 | OH | (H2O), poloxamer, PG |
| 2924, 2856 | C–H alkane | ||
| 1711 | COOH | ||
| 1640 | N–H bend | (sildenafil) | |
| 1085 | C–O |