A Comparative Study to Evaluate the Effect of Different Carbohydrates on the Stability of Immunoglobulin G during Lyophilization and Following Storage

Background: Although the stabilizing effects ofcyclodextrins (CDs) on the liquid protein formulations have been proven, thereis no comprehensive data on evaluation of their effects on the lyophilizedantibody powders. In this study, the influence of two CD derivatives namely beta-cyclodextrin(βCD) and hydroxypropyl beta-cyclodextrin (HPβCD) was compared with trehaloseand mannitol regarding the molecular and thermodynamic stability of lyophilizedIgG formulations as well as its biological activity.Methods: Sugars were separatelyadded to IgG solutions and lyophilization process was conducted. In each groupof carbohydrates, the formulations with lowest amounts of aggregates wereexamined regarding the biological activity. The storage stability of selectedformulations was subsequently determined following 1 and 3 month of storage at45 °C.Results: Trehalose and HPβCDin the ratios of 80% showed the most stabilizing effects by control ofaggregated forms in the orders of 1.02% and 0.83%, respectively. Also, it wasshown that trehalose and HPβCD could incomparably preserve IgG activity invalues of 100% and 96.5%. The results ofDSC and SEM analysis confirmed the existence of crystalline parts in mannitoland βCD formulations of antibody. During the storage time, the lowest rateconstant of aggregation was observed in formulations containing trehalose 80%(0.16/month). All prepared formulations were beta-dominant and no fragmentationwas detected.Conclusion: Molecular,thermodynamic and biological stability of lyophilized IgG was more desirable inthe presence of trehalose and HPβCD in comparison to mannitol and βCD.