Table 3.
Thermal parameters (MDSC analysis) and water content for the freeze dried formulations (n ≥ 3) and predicted Tg (using Fox equation). Uncertainties are standard errors.
| Formulation | Predicted Tg using Fox equation (°C) | MDSC analysis |
Water content (%)d | ||
|---|---|---|---|---|---|
| Tg (midpoint) (°C) ± SD | ΔCp at Tg (J/(g·°C)) ± SD | ΔTg ± SD | |||
| (A) HES + disaccharide | |||||
| HES 5% | 234a | 234 ± 2 | 0.217 ± 0.021 | 9.5 ± 0.5 | 0.28 |
| HES 4% + trehalose 1% | 206 | 182 ± 4 | 0.206 ± 0.017 | 20.0 ± 1.3 | 0.20 |
| HES 2.5% + trehalose 2.5% | 169 | 127 ± 2 | 0.370 ± 0.011 | 15.4 ± 0.7 | 0.26 |
| HES 1% + trehalose 4% | 137 | 114 ± 1 | 0.454 ± 0.009 | 7.9 ± 1.1 | 0.19 |
| Trehalose 5% | 118b | 105 ± 1 | 0.548 ± 0.025 | 6.4 ± 0.4 | 0.28 |
| HES 4% + sucrose 1% | 194 | 170 ± 3 | 0.274 ± 0.022 | 25.7 ± 1.8 | 0.10 |
| HES 2.5% + sucrose 2.5% | 140 | 87 ± 1 | 0.440 ± 0.024 | 8.7 ± 0.2 | 0.35 |
| HES 1% + sucrose 4% | 98 | 73 ± 1 | 0.576 ± 0.023 | 9.9 ± 0.6 | 0.30 |
| Sucrose 5% | 75c | 64 ± 1 | 0.647 ± 0.012 | 6.9 ± 0.4 | 0.55 |
| (B) HES + sorbitol or glycerol | |||||
| HES 5% | 234a | 237 ± 1 | 0.217 ± 0.033 | 8.3 ± 0.9 | not determined |
| + sorbitol 0.5% | 197 | 189 ± 2 | 0.226 ± 0.029 | 15.8 ± 1.5 | not determined |
| + sorbitol 1% | 170 | 36 and 134 | not determined | not determined | not determined |
| + glycerol 0.5% | 165 | 162 ± 4 | 0.199 ± 0.042 | 17.2 ± 2.5 | not determined |
| + glycerol 1% | 121 | 116 ± 3 | 0.259 ± 0.056 | 25.6 ± 7.1 | not determined |
| (C) HES + trehalose 1% + sorbitol or glycerol | |||||
| HES 5% + trehalose 1% | 210 | 197 ± 1 | 0.246 ± 0.021 | 19.8 ± 3.6 | not determined |
| + sorbitol 0.5% | 183 | 156 ± 2 | 0.252 ± 0.003 | 25.8 ± 1.8 | not determined |
| + sorbitol 1% | 162 | not detected | not detected | not determined | not determined |
| + glycerol 0.5% | 157 | 138 ± 4 | 0.283 ± 0.075 | 26.1 ± 7.1 | not determined |
| + glycerol 1% | 120 | not detected | not detected | not determined | not determined |
| (D) HES + trehalose 3% + sorbitol or glycerol | |||||
| HES 5% + trehalose 3% | 183 | 151 ± 2 | 0.307 ± 0.046 | 20.0 ± 3.1 | not determined |
| + sorbitol 0.5% | 166 | 125 ± 1 | 0.365 ± 0.077 | 23.7 ± 3.0 | not determined |
| + sorbitol 1% | 151 | 102 ± 2 | 0.375 ± 0.068 | 23.0 ± 2.7 | not determined |
| + glycerol 0.5% | 147 | 108 ± 3 | 0.360 ± 0.008 | 23.8 ± 1.6 | not determined |
| + glycerol 1% | 120 | 81 ± 1 | 0.348 ± 0.042 | 24.8 ± 1.2 | not determined |
| (E) HES 0.75% + trehalose:glycerol | |||||
| HES 0.75% + trehalose 3% | 137 | 114 ± 5 | 0.490 ± 0.033 | 8.8 ± 0.4 | 0.19 |
| + trehalose 2.91%; glycerol 0.09% | 126 | 97 ± 1 | 0.504 ± 0.012 | 8.9 ± 0.5 | 0.24 |
| + trehalose 2.85%; glycerol 0.15% | 119 | 91 ± 2 | 0.511 ± 0.030 | 11.6 ± 1.8 | 0.21 |
| + trehalose 2.70%; glycerol 0.30% | 102 | 76 ± 1 | 0.503 ± 0.021 | 12.2 ± 0.9 | 0.21 |
| + trehalose 2.55%; glycerol 0.45% | 87 | 62 ± 2 | 0.492 ± 0.027 | 13.3 ± 1.4 | 0.18 |