The Evolution of quality by design (QbD) for biologics.

In recent years, regulators have recognized the need for more controls in drug manufacturing processes. Quality by design is a science- and risk-based approach to drug product development and several pilot programs are ongoing to evaluate enhanced drug development strategies. This article provides a commentary on a recent regulatory publication on the subject of design space verification.

Biopharmaceutical production: Applications of surface plasmon resonance biosensors.

Surface plasmon resonance (SPR) permits the quantitative analysis of therapeutic antibody concentrations and impurities including bacteria, Protein A, Protein G and small molecule ligands leached from chromatography media. The use of surface plasmon resonance has gained popularity within the biopharmaceutical industry due to the automated, label free, real time interaction that may be exploited when using this method. The application areas to assess protein interactions and develop analytical methods for biopharmaceutical downstream process development, quality control, and in-process monitoring are reviewed.

Global Sensitivity Analysis for the determination of parameter importance in bio-manufacturing processes.

The present paper describes the application of GSA (Global Sensitivity Analysis) techniques to mathematical models of bioprocesses in order to rank inputs such as feed titres, flow rates and matrix capacities for the relative influence that each exerts upon outputs such as yield or throughput. GSA enables quantification of both the impact of individual variables on process outputs, as well as their interactions. These data highlight those attributes of a bioprocess which offer the greatest potential for achieving manufacturing improvements.

Evaluation of a novel agarose-based synthetic ligand adsorbent for the recovery of antibodies from ovine serum.

This paper evaluates a prototype agarose-based affinity adsorbent utilizing a bound synthetic ligand designed to replace Protein A as an IgG-affinity capture resin and compares its purification characteristics with four commercially available matrices for the recovery of polyclonal antibodies from crude hyperimmune ovine serum. The novel adsorbent was found to show the highest dynamic capacity (29.2 mg/mL) of all matrices under evaluation--30% higher than the other commercial adsorbents evaluated.

A prototype software methodology for the rapid evaluation of biomanufacturing process options.

A three-layered simulation methodology is described that rapidly evaluates biomanufacturing process options. In each layer, inferior options are screened out, while more promising candidates are evaluated further in the subsequent, more refined layer, which uses more rigorous models that require more data from time-consuming experimentation. Screening ensures laboratory studies are focused only on options showing the greatest potential.

Purification of antibodies using the synthetic affinity ligand absorbent MAbsorbent A2P.

A protocol for the purification of polyclonal antibodies from ovine serum using the synthetic protein A absorbent MAbsorbent A2P is described. Clarified serum is loaded directly onto the affinity column without prior adjustment and albumin and unwanted serum components are washed from the column using a sodium octanoate buffer before elution of bound antibodies. MAbsorbent A2P was shown to bind approximately 27 mg ml(-1) of polyclonal immunoglobulin under overloading conditions, with eluted IgG purities of >90% and minor levels of albumin (approximately 1%).

Decision-support software for the industrial-scale chromatographic purification of antibodies.

The high therapeutic and financial value offered by polyclonal antibodies and their fragments has prompted extensive commercialization for the treatment of a wide range of acute clinical indications. Large-scale manufacture typically includes antibody-specific chromatography steps that employ custom-made affinity matrices to separate product-specific IgG from the remainder of the contaminating antibody repertoire. The high cost of such matrices necessitates efficient process design in order to maximize their economic potential.

Detection and quantification of affinity ligand leaching and specific antibody fragment concentration within chromatographic fractions using surface plasmon resonance.

Rapid analyses of chromatographic steps within a biopharmaceutical manufacturing process are often desirable to evaluate column performance, provide mass balance data and to permit accurate calculations of yields and recoveries. Using SPR (surface plasmon resonance) biosensor (Biacore) technology, we have developed a sandwich immunoassay to quantify polyclonal anti-digoxin Fab fragments used for the production of the FDA (Food and Drug Administration)-approved biotherapeutic DigiFab. The results show that specific Fab may be quantified in all affinity process streams and accurate yield and mass balance data calculated.

Antibody production: polyclonal-derived biotherapeutics.

Antibody based therapies using monoclonal or polyclonal antibodies are emerging as an important therapeutic approach for the treatment of a number of diseases. With increasing emphasis on new technologies associated with monoclonal antibody expression and purification, the clinical need of polyclonal therapeutics for treatment of a variety of specific illnesses and infections is often overlooked. Despite being largely abandoned in the early twentieth century due to the development of antibiotics, polyclonal antibody therapeutics are today widely used in medicine for viral and toxin neutralization and for replacement therapy in patients with immunoglobulin deficiencies.

Characterisation of an industrial affinity process used in the manufacturing of digoxin-specific polyclonal Fab fragments.

This paper describes the effect of several variables on the affinity process for the production of the FDA approved biotherapeutic product Digoxin Immune Fab (Ovine) (DigiFab, Protherics Inc., TN, USA). The study considers the effects of column re-use on matrix capacity and on the subsequent recovery of the antibody product, and the impact of varying column loading on matrix performance.

Optimal conditions for the papain digestion of polyclonal ovine IgG for the production of bio-therapeutic Fab fragments.

In the present paper, we describe a rapid method for the determination of optimum conditions for papain digestion of polyclonal ovine IgG (purified by Na(2)SO(4) precipitation) for the production of bio-therapeutic Fabs (antigen-binding fragments). To determine the optimum conditions for digestion, a factorial approach to the design of experiments was undertaken. The resulting experimental data were used to construct the mathematical models using Design Expert 6.

Optimised affinity purification of polyclonal antibodies from hyper immunised ovine serum using a synthetic Protein A adsorbent, MAbsorbent A2P.

This report describes the applicability of a synthetic chromatography adsorbent for large-scale purification of polyclonal immunoglobulin G from hyper immunised ovine serum. Under optimised conditions, MAbsorbent A2P was shown to bind approximately 27 mg mL(-1) of ovine immunoglobulin from undiluted serum, with eluted IgG purities of >95%, minor levels of albumin (approximately 1%) and undetectable levels of leached ligand in the purified preparations. The results presented here indicate that the optimised affinity capture of immunoglobulin from ovine serum using MAbsorbent A2P is a feasible alternative to Protein A chromatography or sodium sulphate precipitation for the initial capture of antibodies from undiluted serum.