title: Tenecteplase: stability and bioactivity of thawed or diluted solutions used in peripheral thrombolysis.
abstract: OBJECTIVE
  Tenecteplase (TNK; TNKase) is a third-generation plasminogen activator approved for acute myocardial infarction with an enhanced safety profile compared to alteplase. The stability and bioactivity of reconstituted frozen/thawed and diluted tenecteplase solutions used in noncoronary peripheral thrombolysis was determined.
  
  
  METHODS
  Lyophilized TNK was freshly reconstituted in sterile water (5 mg/mL) and used as control. In freeze/thaw studies, reconstituted TNK aliquots were stored frozen for 4 weeks at -20 degrees C, thawed at ambient temperature, and assayed with and without an additional freeze/thaw cycle. Additional freshly reconstituted TNK aliquots were assayed after six freeze/thaw cycles when frozen at two separate temperatures (-20 degrees and -70 degrees C) and thawed at 2-8 degrees C or ambient temperature. In dilution studies, reconstituted TNK was diluted in 500-mL commercially available normal saline solution bags to concentrations of 0.01, 0.02, and 0.05 mg/mL. Samples were assayed after 0, 8, and 24 hours at ambient temperature. Optical clarity, pH, protein concentration, particle counts, and in-vitro clot-lysis assays were performed. Protein monomer (%), single-chain protein (%), and particle counts were performed in freeze/thaw studies.
  
  
  RESULTS
  Frozen/thawed TNK aliquots met all specifications as freshly reconstituted product. For dilution studies (0.01, 0.02, and 0.05 mg/mL), the recovered protein retained 83%-100% bioactivity after 24 hours. The recovered protein rates over the course of 24 hours (relative to target concentration) were 70%-75%, 80%-85%, and 94%-95% at 0.01, 0.02, and 0.05 mg/mL, respectively. Assayed solutions were clear/colorless at all concentrations and time points.
  
  
  CONCLUSIONS
  TNK is fully active after reconstitution and freezing/thawing. TNK dilutions used in clinical practice (0.01-0.05 mg/mL) demonstrated retention of biologic activity at 24 hours without precipitates.
authors.affiliation: Department of Vascular Medicine, Genentech, Inc., South San Francisco, 94080-4990, USA. cpsemba@gene.com
authors.forename: Charles P
authors.initials: CP
authors.lastname: Semba
authors.forename: Suzanne
authors.initials: S
authors.lastname: Weck
authors.forename: Mahmood K
authors.initials: MK
authors.lastname: Razavi
authors.forename: Lisa
authors.initials: L
authors.lastname: Tuomi
authors.forename: Thomas
authors.initials: T
authors.lastname: Patapoff
mesh_terms: D001681:Biological Assay; D004355:Drug Stability; D005343:Fibrinolytic Agents / Q000032:analysis / Q000737:chemistry*; D005615:Freezing; D006801:Humans; D007201:Indicator Dilution Techniques; D012996:Solutions; D000077785:Tenecteplase; D015912:Thrombolytic Therapy; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000032:analysis / Q000737:chemistry*
chemical_list: D005343:Fibrinolytic Agents; D012996:Solutions; D010959:Tissue Plasminogen Activator; D000077785:Tenecteplase