Figure 9: FT-IR spectra of (a) DRZ loaded OCM-CSNPs, (b) Blank OCM-CSNPs, and (c) DRZ powder. DRZ showed a strong absorbance at 3372 cm−1 attributed to the primary amino group. The same peak in OCM-CSNPs disappeared that was a clear indication and that the of DRZ interacted strongly with –COOH of OCM-CS. Abbreviations: OCM-CSNPs, 6-O-carboxymethyl chitosan nanoparticles; DRZ, dorzolamide hydrochloride; FT-IR, Fourier transformation-infrared.