Publications by authors named "Sunitha Kandula"

Precipitation can be used for the removal of impurities early in the downstream purification process of biologics, with the soluble product remaining in the filtrate through microfiltration. The objective of this study was to examine the use of polyallylamine (PAA) precipitation to increase the purity of product via higher host cell protein removal to enhance polysorbate excipient stability to enable a longer shelf life. Experiments were performed using three monoclonal antibodies (mAbs) with different properties of isoelectric point and IgG subclass.

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Membrane chromatography has been established as a viable alternative to packed-bed column chromatography for the purification of therapeutic proteins. Purification via membrane chromatography offers key advantages, including higher productivity and reduced buffer usage. Unlike column chromatography purification, the utilization of high-throughput screening in order to reduce development times and material requirements has been a challenge for membrane chromatography.

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Purification of peptides typically includes expensive reverse phase (RP) processes, which utilize high pressure and large volumes of solvent. For two conjugated peptides, chromatography process development targeted a low-pressure aqueous process that could achieve target product purities of ≥95%, comparable to purities seen with traditional RP. A high throughput screening approach of different modalities was used to identify binding and elution conditions on a cation exchange resin and small-scale columns were used in order to assess impurity removal and process yield.

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Therapeutic manufacturing has become globalized in recent decades, necessitating transportation of drug substance across the world. The outcome of this expansion is significant costs for shipment and added risk of damage to the drug substance containers. There are multiple container options with various materials of construction for storage of Biologics drug substance (DS).

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Protein concentration is a critical product quality attribute and required for any therapeutic protein. Many commercial and investigational new biologics are now formulated at high concentrations (>100 mg/ml) to achieve successful subcutaneous administration. Assaying protein concentration in high concentration formulations poses a challenge, as traditional absorption spectroscopy and UPLC/HPLC (ultra/high performance liquid chromatography) assays cannot accurately measure such high concentrations without further solution manipulation.

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The storage of drug substance at subzero temperatures mitigates potential risks associated with liquid storage, such as degradation and shipping stress, making it the best solution for long-term storage. However, slower (generally uncontrolled) rates of freezing and thawing of drug substance in conventional large storage containers (>2L) can lead to greater cryoconcentration (exclusion of solute molecules) resulting in zones of higher protein and excipient concentrations and changes to the desired formulation pH and excipient concentration. These conditions can negatively impact product quality, thus changing the target product profile.

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High throughput experimental strategies are central to the rapid optimization of biologics purification processes. In this work, we extend common high throughput technologies towards the characterization of a multi-column chromatography process for a monoclonal antibody (mAb). Scale-down strategies were first evaluated by comparing breakthrough, retention, and performance (yields and clearance of aggregates and host cell protein) across miniature and lab scale columns.

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The concept of design space has been taking root as a foundation of in-process control strategies for biopharmaceutical manufacturing processes. During mapping of the process design space, the multidimensional combination of operational variables is studied to quantify the impact on process performance in terms of productivity and product quality. An efficient methodology to map the design space for a monoclonal antibody cell culture process is described.

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Protein A chromatography has become widely established for the preparative purification of mAbs (monoclonal antibodies). Low pH elution from Protein A columns followed by neutralization can often lead to precipitation of impurities in the product stream, leading to a visually turbid solution. Pretreatment of the cell culture harvest stream with an increased surface area of the depth filter was found to reduce the magnitude of this problem through exploitation of the adsorptive properties of harvest depth filters.

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