title: A comparative study on the physicochemical and biological stability of IgG1 and monoclonal antibodies during spray drying process.
abstract: BACKGROUND
  The main concern in formulation of antibodies is the intrinsic instability of these labile compounds. To evaluate the physicochemical stability of antibody in dry powder formulations, physical stability of IgG1 and a monoclonal antibody (trastuzumab) during the spray drying process was studied in a parallel study and the efficacy of some sugar based excipients in protection of antibodies was studied.
  
  
  RESULTS
  The SDS-PAGE analysis showed no fragmentation of antibodies after spray drying in all formulations. The secondary structure of antibodies contained 40.13 to 70.19% of β structure in dry state. Also, CD spectroscopy showed the similar secondary structure for trastuzumab after reconstitution in water. ELISA analysis and cell culture studies were conducted in order to evaluate bioactivity of monoclonal antibody. Formulations containing combination of excipients provided maximum tendency of trastuzumab to attach to the ELISA antigen (86.46% ± 2.3) and maximum bioactivity when incubated with SKBr3 cell line (the cell viability was decreased to 65.99% ± 4.6). Incubation of formulations with L929 cell line proved the biocompatibility of the excipients and non-toxic composition of formulations.
  
  
  CONCLUSIONS
  The IgG1 and trastuzumab demonstrated similar behavior in spray drying process. The combination of excipients containing trahalose, hydroxypropyl beta cyclodextrin and beta cyclodextrin with proper ratio improved the physical and chemical stability of both IgG1 and monoclonal antibody.
authors.forename: Vahid
authors.initials: V
authors.lastname: Ramezani
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran. vatanara@tums.ac.ir.
authors.forename: Alireza
authors.initials: A
authors.lastname: Vatanara
authors.forename: Abdolhossein Rouholamini
authors.initials: AR
authors.lastname: Najafabadi
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Shokrgozar
authors.forename: Alireza
authors.initials: A
authors.lastname: Khabiri
authors.forename: Mohammad
authors.initials: M
authors.lastname: Seyedabadi