Ultrasound for          Particle size        Entrapment efficiency     Drug loading
the second time           (nm)                           (%)                              (%)
(min)

0.5                               95.4                       36.2                              3.49
1                                137.3                       48.2                              4.59
2                                141.7                       40.9                              3.92
4                                212.6                       38.2                              3.67