Sustained Release Formulation
A drug product engineered to release the active compound slowly and continuously over an extended period. For peptide drugs, sustained release technologies include biodegradable polymer microspheres, hydrogels, and lipid-based systems that convert daily injections into monthly or longer-interval treatments.
Technical Context
Key sustained release technologies for peptides: PLGA/PLA microspheres (octreotide LAR, leuprolide depot — polymer degradation releases entrapped peptide over weeks to months; release profile depends on polymer molecular weight, copolymer ratio, and microsphere size), in situ forming implants (PLGA in NMP solvent solidifies upon injection — leuprolide Eligard), self-assembling peptide gels (lanreotide autogel — the peptide itself forms nanotubes at high concentration), hydrogel depots, and lipid-based systems. Design goals: zero-order release kinetics (constant rate), complete peptide release, minimal initial burst (avoiding toxic Cmax), and biocompatible degradation products. Manufacturing complexity and cost are significant — depot formulations are typically more expensive than immediate-release equivalents.