Table 5.
The heats of fusion and the onset and peak temperatures of the melting of methylxanthines in the mixtures in HPMC.
| Content of Caffeine in Mixture (%) |
Heat of Fusion (J/g)
ΔHf |
Onset Temperature (°C)
Ton |
Peak Temperature (°C)
Tp |
| 10 | – | – | – |
| 30 | 3.7 | 220.6 | 233.5 |
| 50 | 20.5 | 235.3 | 239.2 |
| 70 | 34.2 | 235.9 | 238.3 |
| 90 | 82.5 | 235.5 | 237.3 |
| 100 | 103.5 | 236.9 | 237.9 |
| Content of Theophylline in Mixture (%) |
Heat of Fusion (J/g)
Δ Hf |
Onset Temperature (°C)
Ton |
Peak Temperature (°C)
Tp |
| 10 | – | – | – |
| 30 | 20.9 | 249.5 | 268.0 |
| 50 | 62.1 | 261.8 | 270.2 |
| 70 | 83.8 | 268.4 | 272.3 |
| 90 | 125.7 | 271.0 | 273.4 |
| 100 | 155.3 | 271.9 | 273.1 |