Preparation and Characterization Studies of Dorzolamide-Loaded Ophthalmic Implants for Treating Glaucoma.

Objectives: This study constructed dorzolamide (DRZ)-loaded ophthalmic implants for extended drug delivery and increased drug retention.

Materials and methods: Carboxymethyl cellulose (CMC) and chitosan (CHI) were used to describe the ophthalmic implants. The implants were prepared by the solvent casting technique in presence of polyethylene glycol 6000 (PEG 6000) as plasticizer. Physicochemical characterization studies including mechanical characteristics [tensile strength (TS), elongation at break, and Young's modulus], bioadhesion studies, and in vitro and ex vivo drug release studies were conducted.

Results: TS of drug-loaded ophthalmic implants was 10.70 and 11.68 MPa, respectively. Elongation at break of CMC and CHI implants was 62.00% and 59.05%, respectively. The in vitro release profiles fit into Higuchi type kinetic model. Ex vivo release study results for both implants were correlated with in vitro release investigations.

Conclusion: CMC and CHI-based implants provide extended drug delivery. Implants prepared using CMC provided a significantly slower in vitro release rate, and drug retention on ocular surfaces increased. Thus, it has been concluded that DRZ-loaded CMC implants could provide effective treatment for glaucoma.