Table 5.
Characterization of plain chitosan-alginate microparticles (formulation “F14_Low”) batches without (batch A) and with (batches B to H) cryoprotectants addition (sucrose, glucose, or trehalose), on production day and following freeze-drying.
| Batches | Cryoprotectant % (w/v) | ALG:CS:Cryoprotectant Mass Ratio (w/w) | Before Freeze-Drying | After Freeze-Drying | |||
|---|---|---|---|---|---|---|---|
| Particle Size (µm) | Zeta Potential (mV) | Particle Size (µm) | |||||
| d0.5 | Span | d0.5 | Span | ||||
| A | - | 1:1:0 | 13.3 ± 1.0 | 3.1 ± 2.3 | −19.5 ± 0.7 | 170.6 ± 50.8 | 2.6 ± 0.3 |
| B | Sucrose 5% | 1:1:120 | 13.6 ± 0.2 | 1.8 ± 0.5 | +14.9 ± 0.3 | 93.5 ± 15.6 | 2.3 ± 0.1 |
| C | Sucrose 10% | 1:1:240 | 13.2 ± 1.1 | 1.4 ± 0.1 | n.d. | 65.5 ± 7.3 | 2.0 ± 0.2 |
| D | Glucose 5% | 1:1:120 | 12.9 ± 0.0 | 1.8 ± 0.0 | n.d. | 54.1 ± 9.9 | 1.9 ± 0.3 |
| E | Glucose 10% | 1:1:240 | 13.5 ± 2.0 | 2.0 ± 0.7 | +11.6 ± 1.2 | 47.1 ± 8.3 | 2.4 ± 0.2 |
| F | Trehalose 5% | 1:1:120 | 13.2 ± 0.4 | 1.8 ± 0.3 | +13.3 ± 0.5 | 81.9 ± 15.5 | 2.0 ± 0.1 |
| G | Trehalose 10% | 1:1:240 | 12.1 ± 0.6 | 1.4 ± 0.1 | n.d. | 63.7 ± 4.5 | 2.0 ± 0.3 |
The pH of alginate, chitosan and TPP solutions was initially set to 6.7, 4.1 and 9.0, respectively. Results are expressed as mean and standard deviation (n ≥ 3); n.d., not determined.