Intraperitoneal Injection
Injection into the peritoneal cavity (the abdominal space containing the intestines and other organs). This route is primarily used in preclinical animal research rather than routine human therapy and is commonly seen in published peptide compound studies conducted in rodent models.
Technical Context
IP injection delivers drug into the peritoneal cavity (~2L volume in humans), where it is absorbed primarily through the portal venous system (draining to the liver) and lymphatics. The large peritoneal surface area (approximately equal to body surface area ~1.7m²) provides extensive absorption surface. In peptide research, IP injection is the most common route in rodent studies due to ease of administration, large volume capacity, and rapid absorption. IP route is less commonly used in human therapeutics but is employed in peritoneal dialysis settings. When reading preclinical peptide research, IP dosing in animal models should not be directly extrapolated to SC or other routes in humans due to different absorption kinetics and first-pass hepatic exposure.