“…The peaks at 1619 cm À1 represent C=O stretch in hydroxyanthraquinone, and the peak at 1384 cm À1 and the weak peak at 1076 cm À1 attribute to the stretch vibration of C-C bond and C-O bond, respectively. 30 Pure PLGA also has three peaks at 1760 cm À1 (C=O stretch), 1456 cm À1 (methyl stretch), and 1167 cm À1 (saturated bond), respectively. For SF powder, the peaks at 1637, 1533, 1231, and 696 cm À1 attribute to amide I, amide II, amide III, and amide V, respectively.…”