This application note presents the results obtained for the development of different HPLC methods on model therapeutic oligonucleotides, including R&D-grade Nusinersen, an approved 18-mer phosphorothioate oligonucleotide with 2’-O-(2-methoxyethyl) modifications.

A method was developed for the absolute quantification of purified therapeutic oligonucleotides, based on phosphorus determination by ICP-MS/MS.

Two applications are presented here and describe the use of a 2D-LC system for MS characterisation of mAbs without sample preparation.

Charge variants are considered as a Critical Quality Attribute of therapeutic monoclonal antibodies, as they can have a significant impact on the efficacy of the drug. State-of-the-art analytical techniques are required to both quantify and identify the variants. In this application note, we present the portfolio proposed by Quality Assistance, including capillary isoelectric focusing (cIEF) and ion-exchange chromatography (IEX), with applications to commercial monoclonal antibodies. Approaches based on (2D-)LC/MS are presented for the identification of the variants.

Using a QbD approach, we developed a TNFα neutralising assay capable of fulfilling the Analytical Target Profile. Statistical Design of Experiment was applied to evaluate the effect of the different factors and to choose the optimal parameters.

Phosphodiester to phosphorothioate ratio (P=O/P=S) is a critical quality attribute of phosphorothioate oligonucleotides. The determination of this ratio is commonly performed by P-NMR, which requires specific equipment and cannot be easily applied in a regulated (GxP) environment. For the first time, we present in this application note the preliminary results obtained for the development of an ICP-MS/MS method to determine P=O/P=S ratio.

In this application note, we present how this technology can be used to monitor structural changes at the amino acid level during stress testing studies of a monoclonal antibody. This appreach can be applied similarly to stability studies. 

In this application note, we present a case study in which we performed epitope mapping for three monoclonal antibodies binding to an interleukin receptor.