Zahra Ebrahimi - Department of Chemical Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran
Hamid Rashedi - Department of Chemical Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran
Ahmad Fazeli - Biotechnology Group, Department of Chemical Engineering, Tarbiat Modares University, Tehran, Iran

The aggregation of protein is the most prevalent and the most disturbing kind of instability and this challenge exists in almost every stage of the development ofprotein drug. The presence of insoluble aggregations in protein drugs will make the supply of the product a tough job. This study identifies the inhibition of the foldedInterferon beta 1-b’s aggregation with the assistance of some excipients. It uses some thermal stress and mechanical methods to accelerate the aggregation, and alsothe spectroscopic method to identify the protein aggregation and its growth. Experimental data of the tests show compliance with the autocatalytic model. This model has been used to obtain the Kinetic constants of aggregation in different statesand to make comparison with one another in the presence of some excipients. The kinetic constants were obtained by fitting the Autocatalytic model on data. Amongthese excipients, Polysorbate 20 of 0.01% (w/v) showed the best result in decreasing the aggregation. Using this excipient of 0.01% (w/v) in thermal stress causes dramatic reduction of nucleation constant from 8.3 ×10-3 (min-1) to4.14 ×10-6 (min-1), which indicates the reduction of protein aggregation in the solution

Aggregation, Interferon beta 1-b, Autocatalytic Model, Polysorbate 20