The drug aprotinin, is a small protein bovine pancreatic trypsin inhibitor, or basic trypsin inhibitor of bovine pancreas, which is an antifibrinolytic molecule that inhibits trypsin and related proteolytic enzymes. Aprotinin is a Kunitz-type serine protease inhibitor composed of approximately 58 amino acids with a molecular mass near 6.5 kDa and three intramolecular disulfide bonds that stabilize its compact tertiary structure. It binds reversibly to the active site of serine proteases including trypsin, plasmin and plasma kallikrein, forming tight noncovalent complexes that reduce proteolytic cleavage of fibrin and limit activation of the contact system. The molecule is normally supplied as a lyophilized protein following purification from bovine pancreas or by recombinant expression, characterized by activity in kallikrein inhibitor units, and is analyzed by peptide mapping, mass spectrometry, reversed-phase HPLC and size exclusion chromatography to confirm sequence integrity, specific activity and absence of aggregates.
Parent: Aprotinin
Pharmaceutical-grade aprotinin preparations are monitored for peptide- and protein-related impurities, post-translational and degradation variants, and adventitious bovine-derived contaminants; common related compounds include N- or C-terminal truncation products, single-residue substitutions or isoforms, oxidized methionine species, deamidated asparagine or glutamine variants, higher molecular weight aggregates, and residual non-aprotinin bovine proteins and lipopolysaccharide. Typical analytical specification targets used by manufacturers and quality control labs are high purity by RP-HPLC greater than 95 percent, total related impurities below approximately 5 percent area, individual impurity peaks typically limited to 1 to 2 percent area, oxidized species generally controlled below about 2 percent, aggregates by SEC less than 1 percent, and endotoxin and residual host proteins quantified and kept at trace levels consistent with regulatory guidance; these parameters are confirmed by orthogonal methods including LC-MS peptide mapping, SDS-PAGE, SEC, amino acid analysis and validated bioassays for protease inhibitory activity.
Aprotinin is used as an antifibrinolytic agent to reduce perioperative blood loss and the need for transfusion in surgical settings where excessive proteolysis and fibrin degradation occur, historically including complex cardiac surgery, liver transplantation and some other high-bleeding-risk procedures.
No. Aprotinin is not an anticoagulant. It is an antifibrinolytic and protease inhibitor that reduces fibrin breakdown by inhibiting serine proteases such as plasmin and kallikrein, thereby promoting hemostasis rather than preventing clot formation.
Availability of aprotinin varies by country and over time. The product was withdrawn from routine use by its manufacturer following safety reviews, and subsequent regulatory reassessments have led to restricted reintroduction or limited access in some regions; current market status depends on local regulatory decisions and supply arrangements, so check national regulatory authority listings or product labels for up-to-date information.
In some centers and jurisdictions aprotinin remains an option for select high-bleeding-risk cardiac surgery patients under restricted indications and specific protocols, but many hospitals now favor alternative antifibrinolytics such as tranexamic acid; use in cardiac surgery is therefore institution- and region-dependent and guided by local regulatory approval and clinical policies.
