title: The relationship between protein aggregation and molecular mobility below the glass transition temperature of lyophilized formulations containing a monoclonal antibody.
abstract: OBJECTIVE
  To find out if the physical instability of a lyophilized dosage form is related to molecular mobility below the glass transition temperature. Further, to explore if the stability data generated at temperatures below the glass transition temperature can be used to predict the stability of a lyophilized solid under recommended storage conditions.
  
  
  METHODS
  The temperature dependence of relaxation time constant, tau, was obtained for sucrose and trehalose formulations of the monoclonal antibody (5 mg protein/vial) from enthalpy relaxation studies using differential scanning calorimetry. The non-exponentiality parameter, beta, in the relaxation behavior was also obtained using dielectric relaxation spectroscopy.
  
  
  RESULTS
  For both sucrose and trehalose formulations, the variation in tau with temperature could be fitted Vogel-Tammann-Fulcher (VTF) equation. The two formulations exhibited difference sensitivities to temperature. Sucrose formulation was more fragile and exhibited a stronger non-Arrhenius behavior compared to trehalose formulation below glass transition. Both formulations exhibited < 2% aggregation at t/tau values < 10, where t is the time of storage.
  
  
  CONCLUSIONS
  Since the relaxation times for sucrose and trehalose formulations at 5 degrees C are on the order of 10(8) and 10(6) hrs, it is likely that both formulations would undergo very little (< 2%) aggregation in a practical time scale under refrigerated conditions.
authors.affiliation: Department of Pharmaceutical Technologies, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406, USA. Sarma_P_Duddu@sbphrd.com
authors.forename: S P
authors.initials: SP
authors.lastname: Duddu
authors.forename: G
authors.initials: G
authors.lastname: Zhang
authors.forename: P R
authors.initials: PR
authors.lastname: Dal Monte
mesh_terms: D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D011506:Proteins / Q000737:chemistry*; D013395:Sucrose / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics; D014199:Trehalose / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D011506:Proteins; D013395:Sucrose; D014199:Trehalose