Optimization of high-concentration endostatin formulation: Harmonization of excipients ’ contributions on colloidal and conformational stabilities

Publication date: 15 September 2017 Source:International Journal of Pharmaceutics, Volume 530, Issues 1–2 Author(s): Shujing Wang, Xinyi Zhang, Guoliang Wu, Zhou Tian, Feng Qian Recently, increasing research efforts have been devoted into developing high-concentration protein drugs for subcutaneous injection, especially for those with short half-lives and high-dose requirement. Proteins at high concentrations normally present increased colloidal and structural instability, such as aggregation, fibrillation and gelation, which significantly challenges the high-concentration formulation development of protein drugs. Here we used endostatin, a 20kD recombinant protein, as a model drug for high-concentration formulation optimization. The colloidal and conformational stability of endostatin at high concentration of 30mg/mL were investigated in formulations containing various excipients, including saccharides (mannitol, sorbitol and sucrose), salts (ArgHCl and NaCl), and surfactants (tween 20 and 80). Protein fibrillation was characterized and semi-quantified by optical polarized light microscopy and transmission electron microscopy, and the amount of fiber formation at elevated temperature of 40°C was determined. The soluble protein aggregates were characterized by dynamic and static light scattering before and after dilution. The conformational stability were characterized by polyacrylamide gel electrophoresis, fluorescence, circular dichroism, and differential scanning...
Source: International Journal of Pharmaceutics - Category: Drugs & Pharmacology Source Type: research