*3.5.1 Physical appearance*

The physical appearance of nanoparticles can be examined visually for optical clarity, homogeneity, and fluidity, and also microscopically using a scanning electron microscope [37]. **Figure 7** illustrates digital photographs of PLGA nanoparticles [6] compared to PLGA microparticles [7] prepared via an emulsion process. Due to the optical transparency, the nanoparticles appeared as more transparent dispersions than the microparticles, which appeared white.

**Figure 6.** *Flowchart sequence of the steps used for the equations that predict drug release.*
