Table I.
Half-factorial design (25–1) for the optimization of the excipients ratio (formulation) and the spray drying (process) parameters
| RUN | Factor 1 | Factor 2 | Factor 3 | Factor 4 | Factor 5 | Response 1 | Response 2 | Response 3 | Response 4 |
|---|---|---|---|---|---|---|---|---|---|
| leucine:trehalose | mannitol:dextran | Inlet temp. °C | Gas flow | Liquid feed rate ml/min | Yield | Moisture Content % | Particle size | Span | |
| w:w (ratio) | w:w (ratio) | L/h | % | μm | |||||
| 1 | 15.789: 5.263 (3) | 73.684: 5.263 (14) | 155 | 750 | 3.6 | 49.026 | 1.115 | 3.17 | 1.211 |
| 2 | 10.526:10.526 (1) | 76.842: 2.105 (37) | 155 | 750 | 3.6 | 62.48 | 1.735 | 2.94 | 1.151 |
| 3 | 13.158: 7.895 | 75.263: 3.684 (20) | 145 | 500 | 3 | 49.067 | 1.634 | 3.09 | 1.165 |
| 4 | 10.526:10.526 (1) | 76.842: 2.105 (37) | 135 | 450 | 3.6 | 48.44 | 1.614 | 4.60 | 1.603 |
| 5 | 15.789: 5.263 (3) | 73.684: 5.263 (14) | 135 | 450 | 3.6 | 68.8 | 1.613 | 5.03 | 1.705 |
| 6 | 10.526:10.526 (1) | 73.684: 5.263 (14) | 155 | 750 | 2.4 | 53.1067 | 2.045 | 2.83 | 1.095 |
| 7 | 15.789: 5.263 (3) | 73.684: 5.263 (14) | 155 | 450 | 2.4 | 67.213 | 1.400 | 4.36 | 1.494 |
| 8 | 10.526:10.526 (1) | 73.684: 5.263 (14) | 135 | 450 | 2.4 | 58.65 | 1.700 | 4.86 | 1.450 |
| 9 | 10.526:10.526 (1) | 76.842: 2.105 (37) | 155 | 450 | 2.4 | 52.16 | 1.505 | 4.34 | 1.369 |
| 10 | 13.158: 7.895 | 75.263: 3.684 (20) | 145 | 500 | 3 | 47.787 | 1.615 | 3.53 | 1.397 |
| 11 | 15.789: 5.263 (3) | 76.842: 2.105 (37) | 135 | 450 | 2.4 | 59.88 | 1.406 | 4.90 | 1.661 |
| 12 | 15.789: 5.263 (3) | 76.842: 2.105 (37) | 155 | 450 | 3.6 | 75.947 | 1.004 | 4.60 | 1.680 |
| 13 | 15.789: 5.263 (3) | 76.842: 2.105 (37) | 135 | 750 | 3.6 | 56.227 | 1.512 | 3.06 | 1.305 |
| 14 | 10.526:10.526 (1) | 73.684: 5.263 (14) | 135 | 750 | 3.6 | 61.533 | 2.493 | 3.16 | 1.243 |
| 15 | 10.526:10.526 (1) | 73.684: 5.263 (14) | 155 | 450 | 3.6 | 39.707 | 1.804 | 4.35 | 1.561 |
| 16 | 15.789: 5.263 (3) | 76.842: 2.105 (37) | 155 | 750 | 2.4 | 39.453 | 1.637 | 2.69 | 1.002 |
| 17 | 13.158: 7.895 | 75.263: 3.684 (20) | 145 | 500 | 3 | 39.87 | 1.503 | 3.51 | 1.321 |
| 18 | 10.526:10.526 (1) | 76.842: 2.105 (37) | 135 | 750 | 2.4 | 53.973 | 1.813 | 2.92 | 1.112 |
| 19 | 15.789: 5.263 (3) | 73.684: 5.263 (14) | 135 | 750 | 2.4 | 64.027 | 1.923 | 2.89 | 1.148 |
Labeled in bold are three experimental runs to check reproducibility