Optimization of Primary Drying in Lyophilization During Early-Phase Drug Development Using a Definitive Screening Design With Formulation and Process Factors.

Development of optimal drug product (DP) lyophilization cycles is typically accomplished via multiple engineering runs to determine appropriate process parameters. These runs require significant time and product investments, which are especially costly during early phase development when the DP formulation and lyophilization process are often defined simultaneously. Even small changes in the formulation may require a new set of engineering runs to define lyophilization process parameters.

Finite Element Method (FEM) Modeling of Freeze-drying: Monitoring Pharmaceutical Product Robustness During Lyophilization.

Lyophilization is an approach commonly undertaken to formulate drugs that are unstable to be commercialized as ready to use (RTU) solutions. One of the important aspects of commercializing a lyophilized product is to transfer the process parameters that are developed in lab scale lyophilizer to commercial scale without a loss in product quality. This process is often accomplished by costly engineering runs or through an iterative process at the commercial scale.

Modeling the oxidation of methionine residues by peroxides in proteins.

We report the use of molecular modeling to predict the oxidation propensity of methionine residues in proteins. Oxidation of methionine to the sulfoxide form is one of the major degradation pathways for therapeutic proteins. Oxidation can occur during production, formulation, or storage of pharmaceuticals and it often reduces or eliminates biological activity.

Significance of unfolding thermodynamics for predicting aggregation kinetics: a case study on high concentration solutions of a multi-domain protein.

Purpose: To enable aggregation rate prediction over a broad temperature range for complex multi-domain proteins at high concentrations.

Methods: Thermal unfolding, non-isothermal kinetics and storage stability studies were conducted on a model multi-domain protein (MDP) at moderate to high concentrations (25-125 mg/mL) over a broad temperature range (4-40°C).

Results: Storage stability studies indicated the aggregation of MDP in solution to be a second order process.

pH control of nucleophilic/electrophilic oxidation.

Finding formulations that prevent degradation of the active pharmaceutical ingredient is an essential part of drug development. One of the major mechanisms of degradation is oxidation. Oxidative degradation is complex, and can occur via different mechanisms, such as autoxidation, nucleophilic/electrophilic addition, and electron transfer reactions.

Age-dependent oxidation and aggregation of ZnT-1: a role for metal catalyzed oxidation?

Biological aging is associated with the oxidation and/or aggregation of a variety of proteins, which may contribute to the age-dependent loss of function. Protein modification can be caused by multiple chemical mechanisms, which may selectively target specific proteins. Here we show that the ZnT-1 isoform of the family of cation diffusion facilitators suffers age-dependent oxidation and covalent aggregation.

Selective oxidation of Zn2+ -insulin catalyzed by Cu2+.

The purpose of this study is to quantitate the sensitivity of Zn2+ -insulin to oxidation catalyzed by various redox active transition metals, Cu2+, Fe2+, Mn2+, Ni2+, Co2+, Cr3+. Human recombinant insulin (INS) was subjected to oxidation under various conditions in the presence and absence of Zn2+ and ascorbate. The extent of oxidation was monitored by RP-HPLC.

Characterization of the metal-binding site of human prolactin by site-specific metal-catalyzed oxidation.

Site-specific metal-catalyzed oxidation (MCO) was applied to characterize the metal-binding site (MBS) of recombinant human prolactin (hPRL), which belongs to the hematopoietic cytokine family. Copper and ascorbate of various concentrations were used to initiate the oxidation of hPRL, and the oxidation-sensitive motifs were characterized and quantitated by mass spectrometry. Based on the results obtained with 10 microM Cu(2+) and 0.