Table 4.
Effect of pH on particle size distribution, particle surface charge, and yield of production of microparticles prepared with alginate to chitosan mass ratio of 1:1 (F14_Low).
| ALG pH | CS pH | F14 pH | Particle Size, d0.5 (µm) | Span | Zeta Potential (mV) | Production Yield * (%) | Aggregates | ||
|---|---|---|---|---|---|---|---|---|---|
| 3.0 | 3.0 | 3.3 | 44.2 | ±0.9 | 1.5 ± 0.0 | +8.7 | ±0.1 | 6.4% | Yes |
| 4.0 | 3.0 | 3.6 | 31.3 | ±0.3 | 31.0 ± 16.3 | +3.7 | ±0.0 | 12.5% | Yes |
| 5.0 | 3.0 | 3.9 | 16.1 | ±0.1 | 1.3 ± 0.0 | −3.5 | ±0.0 | 11.7% | |
| 6.4 | 3.0 | 4.0 | 15.2 | ±0.2 | 1.4 ± 0.1 | −4.6 | ±0.0 | 17.8% | |
| 7.0 | 3.0 | 4.0 | 18.0 | ±0.4 | 1.3 ± 0.0 | −2.3 | ±0.0 | n.d. | |
| 3.0 | 4.0 | 4.1 | 43.8 | ±1.0 | 1.5 ± 0.0 | +1.8 | ±0.0 | 16.9% | Yes |
| 4.0 | 4.0 | 4.3 | 19.0 | ±0.8 | 1.7 ± 0.0 | −4.9 | ±0.0 | 11.7% | Yes |
| 5.0 | 4.0 | 4.5 | 13.0 | ±0.3 | 2.0 ± 0.1 | −7.3 | ±0.1 | 13.6% | |
| 6.4 | 4.0 | 4.6 | 13.2 | ±0.7 | 1.7 ± 0.0 | −6.2 | ±0.1 | 11.9% | |
| 7.0 | 4.0 | 4.6 | 15.8 | ±0.4 | 1.8 ± 0.0 | −13.4 | ±0.1 | 18.3% | |
| 3.0 | 5.0 | 4.9 | 12.9 | ±0.5 | 6.3 ± 1.2 | −16.3 | ±0.0 | 10.4% | |
| 4.0 | 5.0 | 5.0 | 12.1 | ±0.4 | 3.1 ± 0.5 | −14.8 | ±0.0 | 11.4% | |
| 5.0 | 5.0 | 5.3 | 11.4 | ±0.3 | 3.6 ± 0.5 | −18.6 | ±0.1 | 6.7% | |
| 6.4 | 5.0 | 5.4 | 10.9 | ±0.4 | 2.7 ± 0.4 | −18.9 | ±0.1 | 11.4% | |
| 7.0 | 5.0 | 5.4 | 11.8 | ±0.3 | 2.8 ± 0.4 | −17.8 | ±0.1 | 10.6% | |
| 3.0 | 6.0 | 5.7 | 11.5 | ±0.2 | 5.2 ± 0.3 | −22.4 | ±0.1 | 8.3% | |
| 4.0 | 6.0 | 6.3 | 10.0 | ±0.7 | 7.1 ± 0.8 | −23.7 | ±0.2 | 14.2% | |
| 5.0 | 6.0 | 7.2 | 11.9 | ±0.3 | 4.9 ± 0.3 | −26.3 | ±0.1 | 14.6% | |
| 6.4 | 6.0 | 7.5 | 11.4 | ±0.2 | 3.3 ± 0.4 | −25.7 | ±0.1 | n.d. | |
| 7.0 | 6.0 | 7.6 | 13.8 | ±0.3 | 2.3 ± 0.0 | −21.8 | ±0.2 | n.d. | |
F14, microparticles obtained using formulation Method (III) with low molecular weight/92% deacetylation degree chitosan (CS), and low viscosity / high-G sodium alginate (ALG) (Protanal™ LF 10/60). Results are expressed as mean and standard deviation (n ≥ 3). *Production yield was determined using gravimetric determination of particles mass following lyophilisation, and it is expressed as mass percentage (w/w), referred to particles theoretical mass; n.d., not determined.