In considering the congruency of drug and polymer release, our SRS (semi-)quan ta ve imaging of the buffer-rich phase with the 20 wt% and 40 wt% drug loadings, suggests that the drug and polymer do not release congruently (i.e. propor onately), with significant polymer release and an apparent drug concentra on in the buffer well below the 20:80 wt% and 40:60 wt% drug-to-polymer ra os, respec vely (at 60 and 80% wt% drug loadings, neither drug nor polymer release was readily detectable).