Table II.
Examples of PLG Microsphere Formulations Studied for Controlled Release of Proteins and Larger Peptides
| Protein or peptide | Polymer | Summary of results |
|---|---|---|
| α-Chymotrypsin | 50:50 PLG (60 kDa) | 70% burst, additional 10% over 50 days (21) |
| Cyclosporin A | 50:50 PLG (0.44 and 0.80 dl/g) | No drug–polymer interaction biphasic release; 1–40% burst, >28-day release (22) |
| Interferon-α | 50:50 PLG | 11.0% burst w/in 1 h, additional 16.3% released over 21 days (15) |
| Lysozyme | 50:50 PLG | 50% burst, additional 10% over 50 days (23) |
| Lysozyme | 50:50 PLG (10 kDa) | 40% burst, additional 40% over 6 days; reduced activity upon encapsulation (24) |
| Ribonuclease A | 85:15 PLG | 15% burst, additional 50% over 3 months; reduced activity upon encapsulation (16) |
| Somatostatin analog | 55:45 PLG (23–76 kDa) | Release decreased with media ionic strength; <20% burst, continuous or triphasic release for >30 days (25) |
| Tetanus toxoid | 50:50 PLG (100 kDa) | <30% burst, continuous or triphasic for >30 days (26) |
| Thyrotropin | 75:25 PLG (11 kDa) | <20% burst, 30-day continuous release (27) |