Table 1. . Optimization studies for orlistat encapsulation in PLGA-b-PEG nanoparticles.
| Entry | Sample ID | Formulation | Mean size (nm)† before and after filtration through 0.45 µm filter | PDI‡ before and after filtration through 0.45 µm filter | ζ potential before and after filtration through 0.45 µm filter | Orlistat EE and loading efficiency (%) | Orlistat (concentration)§ |
|---|---|---|---|---|---|---|---|
| 1 |
NP-231 |
Nanoprecipitation 2% PVA (2 ml) DCM (1 ml) |
352.5 (149.4) |
0.466 (0.169) |
-32.7 (1.8) |
ND§ |
ND§ |
| 2 |
NP-232 |
Nanoprecipitation 1% PVA (5 ml) DCM (1 ml) |
272.7 (159.3) |
0.496 (0.170) |
-26.0 (-16.0) |
ND§ |
ND§ |
| 3 |
NP-233 |
Emulsion-diffusion-evaporation 2% PVA (2 ml) EA (1 ml) Water (5 ml) |
138.9 (138.3) |
0.201 (0.181) |
-20.2 (-25.3) |
72.1 (7.21)¶ |
240.3 µg/ml¶ |
| 4 | NP-234 | Nanoprecipitation 1% Tween 80 (5 ml) 3% Span 80 (1 ml) |
248.7 (172.8) | 0.524 (0.428) | -12.2 (-29.4) | ND§ | ND§ |
†Average of three dynamic light scattering experiments.
‡PDI (average of three dynamic light scattering readings).
§Not determined.
¶Determined by HPLC.
DCM: Dichloromethane; EA: Ethyl acetate; EE: Encapsulation efficiency; ND: Not determined; PDI: Polydispersity index; PLGA: Poly(lactic-co-glycolic acid); PVA: Polyvinyl alcohol.