Table 3.
Stability of nanoemulsion prepared by Tween 20 and emulsifier combination Span 80:Brij 35 stored under temperature of 4 °C and 25 °C respectively (mean ± S.D., n = 3).
| Storage Duration (Days) | 0 * | 7 | 14 | 21 | 28 | ||||
|---|---|---|---|---|---|---|---|---|---|
| (a) Emulsion prepared by Tween 20: | |||||||||
| Storage temperature (°C) | 25 | 4 | 25 | 4 | 25 | 4 | 25 | 4 | 25 |
| Z-average diameter (nm) | 72.5 ± 1.3 | 70.7 ± 1.8 | 73.4 ± 1.3 | 71.1 ± 1.6 | 73.6 ± 1.1 | 69.2 ± 1.8 | 72.8 ± 0.7 | 70.2 ± 1.3 | 73.9 ± 0.2 |
| PDI | 0.146 ± 0.006 | 0.151 ± 0.003 | 0.144 ± 0.003 | 0.151 ± 0.007 | 0.140 ± 0.005 | 0.151 ± 0.000 | 0.134 ± 0.006 | 0.149 ± 0.003 | 0.133 ± 0.009 |
| ζ-potential (mV) | −43.6 ± 1.4 | −43.2 ± 0.9 | −44.9 ± 1.0 | −43.3 ± 2.8 | −43.5 ± 2.2 | −42.2 ± 1.0 | −42.6 ±0.9 | −41.6 ± 0.6 | −41.9 ± 0.5 |
| (b) Emulsion prepared by Span 80:Brij 35 (0.4:0.6 w/w) | |||||||||
| Z-average diameter (nm) | 66.2 ± 0.5 | 62.8 ± 0.7 | 66.2 ± 0.4 | 62.4 ± 0.8 | 66.0 ± 0.3 | 62.4 ± 1.1 | 65.8 ± 0.7 | 63.2 ± 1.2 | 66.2 ± 0.5 |
| PDI | 0.144 ± 0.007 | 0.162 ± 0.005 | 0.149 ± 0.003 | 0.162 ± 0.003 | 0.157 ± 0.005 | 0.162 ± 0.006 | 0.152 ± 0.002 | 0.160 ± 0.008 | 0.151 ± 0.005 |
| ζ-potential (mV) | −35.9 ± 0.4 | −43.2 ± 2.2 | −45.0 ± 0.8 | −43.1 ± 0.6 | −45.6 ± 1.1 | −42.7 ± 1.0 | −44.8 ± 1.0 | −43.0 ± 1.7 | −44.9 ± 0.5 |
* One day zero, the Z-average diameter (nm) and PDI was only reported at room temperature (25 °C). As soon as the nanoemulsion was prepared, analysis of droplet size and PDI was carried out on the same day.