Formulation
The specific composition and preparation of a pharmaceutical product including active ingredient, excipients, and physical form. Different formulations of the same peptide can have vastly different properties — semaglutide exists as a subcutaneous injection and an oral tablet with completely different formulation approaches.
Technical Context
Formulation development for peptide drugs follows ICH Q8 quality by design (QbD) principles: define target product profile (TPP) → identify critical quality attributes (CQAs: purity, potency, aggregation, particulates) → design formulation to achieve CQAs using design of experiments (DoE) and risk assessment. Key formulation decisions: liquid vs lyophilised (liquid is more convenient but peptides are often less stable in solution — liquid formulations require careful excipient selection; lyophilised products require reconstitution but offer better long-term stability), single-dose vs multi-dose (multi-dose requires preservative — preservative compatibility with peptide must be verified), and device selection (vial/syringe vs pen vs auto-injector — affects formulation volume, concentration, and viscosity requirements). Semaglutide example: Ozempic/Wegovy are multi-dose pen formulations containing semaglutide with disodium phosphate dihydrate, propylene glycol, and phenol (preservative).