Liquid-liquid phase separa on (LLPS), resul ng in the presence of drug-rich droplets within the dissolu on medium, has been widely reported for ASDs . Upon close inspec on of the SRS images (Figure ), a very few drug rich droplets within the buffer-rich phase are visible from 5 min onwards (as magenta dots, highlighted with zoom in Figure ). In this example, these are not of sufficient quan ty and size to be represented as fluctua ons in the drug coefficient line plot (with coefficient values remaining close to 0 throughout the buffer-rich phase). However, strong (non-chemically specific) evidence of nanodroplet forma on in the buffer-rich phase (below the spa al resolu on of the SRS microscope) is provided by the correla ve confocal reflec on images, in which localized reflec ons in the buffer-rich phase (white dots) are visible from 5 min onwards, together with clear oscilla ons in the reflec on coefficients (Figure ). A video of the movement of these nanodroplets is also present in the Suppor ng Informa on (Video S 1). Furthermore, in a separate example (vide infra) of a 20% drug loading film (replicate sample) a er 30 min of buffer exposure, more pronounced LLPS with larger droplet sizes is clearly visible with SRS depth profiling (Figure ).