Definition of Ocuserts:
Thin, flexible polymeric devices placed in the conjunctival sac to release drugs at a controlled rate over a prolonged period.
Classification
Physical State: Soluble (dissolves) vs. insoluble (requires removal).
Drug Release Mechanism:
Reservoir Systems: Drug diffuses through a rate-controlling membrane.
Matrix Systems: Drug uniformly dispersed in a polymer matrix.
Location of Application: Conjunctival or corneal placement.
Duration of Action: Short-term (hours to a day) vs. long-term (days to weeks).
Biodegradability: Biodegradable (breaks down) vs. non-biodegradable (requires removal).
Composition
Drug Reservoir: Holds the drug in a polymer matrix.
Rate-Controlling Membrane: Regulates drug release.
Back Layer: Prevents drug release away from the target.
Advantages
Controlled Release: Maintains therapeutic levels, reducing side effects.
Reduced Dosing Frequency: Prolonged drug delivery improves compliance.
Localized Action: Minimizes systemic absorption and side effects.
Limitations
Comfort Issues: Some patients may feel the device.
Risk of Loss: Ocusert may dislodge.
Infection Risk: Prolonged presence increases infection potential.
Complex Manufacturing: Requires specialized facilities.
Applications
First used for pilocarpine delivery in glaucoma treatment, providing a week-long release compared to multiple daily doses of eye drops.