Table 4.
Comparison of Delivery Systems
|
Delivery System |
Advantages |
Disadvantages |
|---|---|---|
| Liposome (e.g., Visudyne) | • Capable of treating CNV lesions >50% classic for clinical use Prevent long term cytotoxicity | • Incapable of treating CNV lesions <50% classic |
| • Particle size of 120−125 nm | • Require reconstitution before intravenous infusion | |
| • Biodegradable | • Require repeated treatments | |
| • Accommodate oxidative degradable lipid or photo-polymerizable lipid and ballasted cyanine dyes Triggered release system | • Accumulate in other parts of the body besides targeted tissue | |
| • Flexible and high loading capacity | • Reduced efficiency in the presence of serum | |
| |
|
• Potential toxicity still remaining |
| Polymeric Micelle | • Effectively occlude CNV lesions in experimental animal studies | • Not internalized rapidly by various cell types |
| • Reduced toxicity | • Require reconstitution before intravenous infusion | |
| • Particle size of 50−100 nm | • Require repeated treatments | |
| • Dissociate gradually avoiding damage to ocular vessels | • Accumulate in other parts of the body besides targeted tissue | |
| • Ability to package pDNA and provide appreciable gene expression to the conjunctival tissue in research | ||
| |
• Effectively occlude CNV lesions in research studies |
|
| Vectosome | • Selectively modulate the expression of a given gene in animal studies | • Mechanism of action and dosage administration not yet physically observed and established |
| • Remain strictly in the cytoplasm until activated | • Antisense oligonucleotides have a very short half life | |
| • Spherical particles of 0.3−1 μm diameter | • Potential skin photosensitivity | |
| • Form well delineated endsomelike vesicles accommodating different fluorophores in cell cytoplasm | ||
| • Triggered release system | ||
| |
• Internalized rapidly by various cell types and not affected by serum |
|
| Hydrogel | • Maintain controlled drug release while protecting encapsulated drug or gene | • Dosage administration not yet physically observed and established |
| • Biodegradable | • Slow response time | |
| • Stimuli-mediated release | • Possible toxic monomers | |
| • Thermosensitive | • Potential sustained skin photosensitivity |