A simple reversed phase high-performance liquid chromatography method for polysorbate 80 quantitation in monoclonal antibody drug products.

In this paper, we discuss an improved high-performance liquid chromatography (HPLC) method for the quantitation of polysorbate 80 (polyoxyethylenesorbitan monooleate), a commonly used stabilizing excipient in therapeutic drug solutions. This method is performed by quantitation of oleic acid, a hydrolysis product of polysorbate 80. Using base hydrolysis, polysorbate 80 releases the oleic acid at a 1:1 molar ratio. The oleic acid can then be separated from other polysorbate 80 hydrolysis products and matrices using reversed phase HPLC. The oleic acid is monitored without derivatization using the absorbance at 195 nm. The method was validated and also shown to be accurate for the quantitation of polysorbate 80 in a high protein concentration monoclonal antibody drug product. For the measured polysorbate 80 concentrations, the repeatability was less than 6.2% relative standard deviation of the mean (% RSD) with the day-to-day intermediate precision being less than 8.2% RSD. The accuracy of the oleic acid quantitation averaged 94-109% in different IgG(1) and IgG(4) drug solutions with variable polysorbate 80 concentrations. In this study, polyoxyethylene, a by-product of the polysorbate 80 hydrolysis was also identified. This peak was not identified by previous methods and also increased proportionally to the polysorbate 80 concentration. We have developed and qualified a method which uses common equipment found in most laboratories and is usable over a range of monoclonal antibody subclasses and protein concentrations.

A quantitative human monoclonal antibody immunoassay using anti-idiotypic antibody as a membrane antigen surrogate with surface-plasmon-resonance detection.

Biologically active membrane proteins are difficult to isolate. Very often the isolated membrane proteins have low binding affinity or no biological integrity at all. Despite some success in isolation, one has to overcome the hurdles of obtaining sufficient quantity of the proteins and maintaining biological activity upon coating them on surfaces for developing an ELISA. Thus an alternative approach may be useful. The present study describes a quantification assay method for a therapeutic hmAb-1 (human monoclonal antibody-1) that recognizes a cell-surface protein employing an anti-ID (anti-idiotypic antibody) to hmAb-1 as a surrogate antigen in an immunoassay format using surface- plasmon-resonance technology. This assay is applicable for quantification of hmAb-1 in process streams, final drug-product quality control, as well as low-concentration drug substances in intravenous-solution bags. The surrogate nature of the anti-ID was confirmed by demonstrating that the anti-ID displaced the interaction between the hmAb-1 and its membrane antigen in a FACS titration test. The assay format involves first capturing hmAb-1 on the flow-cell surface, which then binds quantitatively to anti-ID in a mixture of increasing quantity of hmAb-1 in solution. An inverse dose-response relation between this anti-ID bound signal (or resonance units) and hmAb-1 concentration was established. The dose-response range of the calibration curve for hmAb-1 was between 20 and 300 ng/ml. The precision, accuracy and specificity of the assay are reported in the present paper.

Evaluation of oligosaccharide methods for carbohydrate analysis in a fully human monoclonal antibody and comparison of the results to the monosaccharide composition determination by a novel calculation.

Carbohydrates can change a drug's properties including solubility, affinity towards antigen, pharmacokinetics and pharmacodynamics. Due to this importance, carbohydrate composition is utilized as a parameter to evaluate a drug candidate's quality. In this study, the compositional monosaccharides of a drug candidate are measured by HPAEC-PAD, while the oligosaccharides are studied by HPAEC-PAD, CE-LIF and LC-MS. The advantages and limitations of these various approaches for oligosaccharide analysis are reviewed in this work. While the methods used for oligosaccharide analysis are well established we have devised a new and novel calculation for determining monosaccharide content using the relative percentages of the N-glycans. This calculation was used to evaluate the accuracy of the oligosaccharide determination methods by comparison of the N-glycan data to the experimental monosaccharide data. The results obtained from this novel calculation demonstrate that the relative abundance of carbohydrates as determined from these various approaches are consistent.