Ophthalmic drugs polymeric delivery systems

Fitzgerald, P., and Wilson, C. G. (1994), Polymeric systems for ophthalmic drug delivery, in Dimitriuitra S., Ed., Polymeric Biomaterials, Marcel Dekker, New York, pp. 373-398. 

Xinming, L., Yingde, C., Lloyd, A. W. et al. 2008. Polymeric hydrogels for novel contact lens-based ophthalmic drug delivery systems. Contact Lens and Anterior Eye M 57-64. 

Frequent instillation of solution or higher drug concentration is needed to achieve the desired therapeutic response. But this attempt is potentially dangerous if drug solution drained from the eye is systemically absorbed from the nasolacrimal duct. To increase precorneal residence time and ocular bioavailability, different ophthalmic delivery systems such as viscous solutions, ointments, gels, suspensions, or polymeric inserts are used. But because of blurred vision (e.g., ointments) or lack of patient compliance (e.g., inserts), these formulations have not been widely accepted. 

Various methods to prepare polymeric hydrogels for novel CL-based ophthalmic drug delivery systems are critically analyzed in Section 51.4.8. In addition, advantages and limitations of CLs as drug carriers and then a more extensive analysis of the approaches made to modify the polymeric networks at the nanoscale in order to improve drug loading and release performance will be discussed. 

POLYMERIC OPHTHALMIC DRUG DELIVERY SYSTEMS PREPARATION AND EVALUATION OF PILOCARPINE-CONTAINING INSERTS... 

The development of polymeric drug delivery devices for sustained ophthalmic CsA release is an active area of research for uveitis, vitreous inflammation, dry eye, and prevention of cornea transplant rejection. The use of these specialized CsA-delivering ophthalmic systems (e.g., implants nanoparticle and microsphere injections) cannot be completely reviewed in this chapter and readers are referred to an alternative text. A sample of applicable polymers for delivery of CsA for uveitis and vitreous inflammation is offered in the accompanying table (Table 15.4). The treatment of posterior uveitis and vitreous inflammation usually involves chronic therapy (often years) of topical agents and frequent intravitreal injections for disease control. These therapies are often impractical and subject to medical non-adherence [33]. Polymeric implants or injectable polymer sustained release systems can potentially improve patient outcomes through optimized intraocular drug concentrations. 

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