A Case Study in Application of the Risk Knowledge Infinity Cycle.

The Risk Knowledge Infinity (RKI) Cycle Framework was featured as part of the ICH-sanctioned training materials supporting the recent issuance of ICH Q9(R1) Quality Risk Management To support ICH Q9(R1) understanding and adoption, this paper presents a case study on the application of the RKI Cycle, based on an underlying out-of-specification investigation. This case study provides a stepwise walk-through of the cycle to illustrate how key concepts within the ICH Q9(R1) revision can be achieved through better connecting quality risk management and knowledge management with a framework such as the RKI Cycle.

Parkinson's Disease: Advances in Treatment and the Syntheses of Various Classes of Pharmaceutical Drug Substances.

An overview of Parkinson's disease (PD) prevalence, diagnosis, and currently available treatment options is provided. A comprehensive list of different classes of marketed pharmaceutical drug products and the syntheses of various drug substances are summarized based on published literature.

Mechanistic evaluation of virus clearance by depth filtration.

Virus clearance by depth filtration has not been well-understood mechanistically due to lack of quantitative data on filter charge characteristics and absence of systematic studies. It is generally believed that both electrostatic interactions and sized based mechanical entrapment contribute to virus clearance by depth filtration. In order to establish whether the effectiveness of virus clearance correlates with the charge characteristics of a given depth filter, a counter-ion displacement technique was employed to determine the ionic capacity for several depth filters. Two depth filters (Millipore B1HC and X0HC) with significant differences in ionic capacities were selected and evaluated for their ability to eliminate viruses. The high ionic capacity X0HC filter showed complete porcine parvovirus (PPV) clearance (eliminating the spiked viruses to below the limit of detection) under low conductivity conditions (≤2.5 mS/cm), achieving a log10 reduction factor (LRF) of > 4.8. On the other hand, the low ionic capacity B1HC filter achieved only ∼2.1-3.0 LRF of PPV clearance under the same conditions. These results indicate that parvovirus clearance by these two depth filters are mainly achieved via electrostatic interactions between the filters and PPV. When much larger xenotropic murine leukemia virus (XMuLV) was used as the model virus, complete retrovirus clearance was obtained under all conditions evaluated for both depth filters, suggesting the involvement of mechanisms other than just electrostatic interactions in XMuLV clearance.

Effects of resin ligand density on yield and impurity clearance in preparative cation exchange chromatography. I. Mechanistic evaluation.

The effects of resin ligand density on cation exchange chromatography performance in preparative monoclonal antibody purification processes were evaluated. A set of agarose-based cation exchange resins spanning a relatively wide range of ligand densities was tested using three different monoclonal antibodies with unique impurity profiles. Experiments were performed in bind-and-elute mode using gradient elution at both intermediate protein loadings and near saturation capacity. Ligand density did not affect clearance of high molecular weight variants under any of the conditions tested; however, ligand density did affect resolution of a basic charge variant in one case and changed host cell protein clearance in another instance. In general, the results indicate that the relationships between ligand density, retention, and resolution are affected by both characteristic charge and protein surface charge distribution.

Effects of resin ligand density on yield and impurity clearance in preparative cation exchange chromatography. II. Process characterization.

Ion exchange resins are key raw materials in biopharmaceutical manufacturing processes, and variability in ligand density has the potential to compromise process robustness if not controlled within appropriate ranges. In this study, yield and impurity clearance were evaluated for several preparative cation exchange chromatography steps using SP Sepharose™ Fast Flow resins at the high, low, and center of the commercial ligand density specification range. This was accomplished using a design of experiments (DoE) approach coupled to high-throughput screening in 96-well plate format, as well as column chromatography experiments with gradient elution. Results of the DoE study indicated that ligand density variation within the commercial specification range of SP Sepharose™ Fast Flow had no effect on yield, HCP clearance, aggregate clearance, or distribution of charge variants. However, results from the column experiments showed that ligand density has the potential to influence protein elution profiles which can lead to small changes in impurity clearance in some cases.

Understanding and mitigating conductivity transitions in weak cation exchange chromatography.

Large conductivity fluctuations were observed during a high pH wash step in a weak cation exchange chromatography process. These conductivity transitions resulted in a conductivity drop during pH increase and a conductivity rise during pH decrease. In some cases, the absolute conductivity change was greater than 6mS/cm which was sufficient to affect target protein retention on the column. Further investigation revealed that wash buffer concentration, resin ligand density, and resin ligand pK have a profound effect on the magnitude of the conductivity transitions and the shape of corresponding pH traces. A potentiometric electrode selective for sodium ions was used to measure effluent counterion concentrations from two preparative resins during high pH washes, and the number of exchangeable counterions was compared to predictions made using ion exchange equilibrium theory. Results from this analysis show that conductivity transitions can be effectively mitigated without compromising process performance by optimizing the trade-off between wash buffer concentration and wash phase duration.

Loading, stationary phase, and salt effects during hydrophobic interaction chromatography: alpha-lactalbumin is stabilized at high loadings.

Amide hydrogen-deuterium exchange labeling has been used to study the effects of salt and protein loading on alpha-lactalbumin (BLA) stability during hydrophobic interaction chromatography (HIC). Stability in the adsorbed phase increased dramatically with increasing loading, and unfolding was nearly undetectable close to the resin saturation capacity. We also found that a butyl surface destabilized BLA more than a phenyl surface, despite the fact that BLA was bound more strongly on the phenyl surface. These observations have important implications for HIC process design and indicate that in some cases column capacity does not have to be sacrificed to preserve protein stability.