Depot Injection
A long-acting injectable formulation that releases the peptide slowly from the injection site over weeks to months. Octreotide LAR uses biodegradable microspheres for monthly dosing, and leuprolide depot is available in preparations lasting 1-6 months.
Technical Context
Depot technologies for peptide drugs include: PLGA microspheres (poly(lactic-co-glycolic acid) — octreotide LAR and some leuprolide formulations use 10-100μm biodegradable microspheres that erode over weeks, releasing peptide; reconstitution technique is critical), PLGA/PLA solid implants (leuprolide Eligard uses in situ forming gel — a polymer solution that solidifies upon SC injection), and self-assembling nanotubes (lanreotide autogel — the peptide itself forms nanotubes at high concentration, creating a viscous gel that slowly releases monomeric peptide). Depot formulations transform daily-injection peptides into monthly or longer-interval treatments, dramatically improving adherence and quality of life.