Table I.
Entrapment efficiency of siRNA and PEI in the PLGA MPs
| MP contents | PLGA MP yield (%)a | Theoretical loading (μg/mg PLGA MPs)b | Entrapment efficiency (% of theoretical loading)c | MP diameter (μm)d |
|---|---|---|---|---|
| siRNA1-PEI polyplexes | 64 ± 5 | siRNA: 7.4 ± 0.5 | siRNA: 85 ± 12 | 18 ± 1 |
| PEI: 11.0 ± 1.0 | PEI: 76 ± 7 | |||
| siRNA2-PEI polyplexes | 68 ± 5 | siRNA: 6.1 ± 0.3 | siRNA: 91 ± 11 | 18 ± 1 |
| PEI: 13.0 ± 1.0 | PEI: 78 ± 5 | |||
| Blank | 83 ± 2 | none | none | 15 ± 2 |
a
Final weight of PLGA MPs as a percentage of the starting amount of PLGA and PEG (248 mg per batch). Values represent average ± standard deviation of n = 3 batches.
b
Calculated by dividing the amount of either siRNA (1100 μg) or r-PEI (2000 μg) added during synthesis by the actual weight of PLGA MPs from that batch.
c
Entrapment efficiency of either siRNA or r-PEI calculated from: (amount extracted from 15 mg PLGA MPs)/(theoretical loading) × 100%.
d
Determined via Coulter Counter analysis of (n = 1500) MPs per batch. Values shown are average ± standard deviation of (n = 3 batches) for each MP type.