Figure 10: FT-IR spectra of (a) DRZ loaded CSNPs, (b) blank CSNPs, and (c) DRZ powder. The broadened peak in the range 3300–3400 cm−1 was due to overlap of the primary amino and hydroxyl peaks. The peaks of DRZ at 1537 and 1344 cm−1 were visible in DRZ loaded CSNs, a clear indication that no ionic interaction occurred between the DRZ and CS and the entrapment of DRZ was merely of a physical type. Abbreviations: CSNPs, chitosan nanoparticles; DRZ, dorzolamide hydrochloride; FT-IR, Fourier transformation infrared.