The Osmolality and Hemolysis of High-Concentration Monoclonal Antibody Formulations.

PURPOSES: Highly concentrated monoclonal antibody (mAb) formulations for subcutaneous administration are becoming increasingly preferred within the biopharmaceutical industry for ease of use and improved patient compliance. A common phenomenon observed in the industry is that osmolality detected via freezing-point depression (FPD) in high-concentration mAb formulations is much higher than the theoretical concentrations, yet the occurrence of this phenomenon and its possible safety issues have been rarely reported. METHODS: The current study summarized theoretical osmolality of U.S. Food and Drug Administration approved high-concentration mAb formulations and evaluated effects of high osmolality on safety using hemolysis experiments for the first time. Two mAbs formulated at 150 mg/mL were used as models and configured into two isotonic solutions: a, a theoretically calculated molarity in the isotonic range (H) and b, an osmolality value measured via the FPD in the isotonic range (I). The H and I formulations of each mAb were individually subjected to hemolysis experiments, and the hemolysis rates of the two formulations of the same mAb were compared. Besides, the effect of mAb concentration on osmolality detected by FPD was explored as well. RESULTS: The results indicated that the hemolysis rates were similar between the H and I formulations of mAbs at the same sample addition volume, and the osmolality values increased approximately linearly with the increase in mAb concentration. CONCLUSIONS: High osmolality for high-concentration mAb formulations would not affect product safety and the excipients could be added at relatively high levels to maintain product stability, especially for labile products.

Freeze-Dried Biopharmaceutical Formulations are Surprisingly Less Stable than Liquid Formulations during Dropping.

PURPOSES: This article describes an interesting phenomenon in which optimized freeze-dried (FD) biopharmaceutical formulations are generally more prone to degradation than their liquid counterparts during dropping and proposes an underlying cause for this surprising phenomenon. METHODS: Two monoclonal antibodies (mAbs) and a fusion protein (FP) were used as model biopharmaceuticals. The stability after dropping stress was determined by ultraviolet-visible (UV-Vis), size exclusion high-performance liquid chromatography (SE-HPLC), micro-flow imaging (MFI), and dynamic light scattering (DLS). RESULTS: Contrary to what we would normally assume, the FD formulations of the three biopharmaceuticals studied here generally showed much higher amounts of protein sub-visible particles (SbVPs) than liquid formulations after applying the same dropping stress as determined by MFI and DLS. Traditional techniques, such as UV-Vis and SE-HPLC, could hardly detect such degradation. CONCLUSIONS: We propose that the higher temperature caused by dropping for the FD powders than the liquid formulations was probably one of the root causes for the higher amount of particles formed for the FD powders. We also recommend that dropping stress should be included for early-stage screening and choosing liquid versus FD biopharmaceutical formulations.

Copper-Catalyzed Remote C(sp3)-H Amination of Carboxamides.

Here we report a method for the site-selective intermolecular C(sp3)-H amination of carboxamides by merging transition-metal catalysis and the hydrogen atom transfer strategy. The reaction proceeds through a sequence of favorable single-electron transfer, 1,5-hydrogen atom transfer, and C-N cross-coupling steps, thus allowing access to a series of desired products. This reaction could accommodate a wide diversity of nitrogen nucleophiles as well as demonstrate excellent chemoselectivity and functional group compatibility.