Pharmacokinetics

Pharmacokinetics (PK) is the branch of pharmacology that studies the time course of a drug's absorption, distribution, metabolism, and excretion (ADME). Key PK parameters include bioavailability, volume of distribution, clearance, half-life, maximum plasma concentration, and time to maximum concentration. For peptides, PK is particularly important because their protein-based nature makes them susceptible to rapid enzymatic degradation, limiting oral bioavailability and requiring parenteral administration. Understanding PK is essential for designing effective dosing regimens: CJC-1295's extended PK profile (6-8 day half-life) allows less frequent dosing than native GHRH (7-minute half-life), while tirzepatide's ~5-day half-life supports once-weekly administration. ORYN's pen systems are designed to deliver consistent subcutaneous doses that achieve predictable pharmacokinetic profiles.