Modular and tunable alternative surfactants for biopharmaceuticals provide insights into Surfactant's Structure-Function relationship

Surface-induced aggregation of protein therapeutics is opposed by employing surfactants, which are ubiquitously used in drug product development, with polysorbates being the gold standard. Since poloxamer 188 is currently the only generally accepted polysorbate alternative, but cannot be ubiquitously applied, there is a strong need to develop surfactant alternatives for protein biologics that would complement and possibly overcome known drawbacks of existing surfactants. Yet, a severe lack of structure-function relationship knowledge complicates the development of new surfactants. Herein, we perform a systematic analysis of the structure-function relationship of three classes of novel alternative surfactants. Firstly, the mode of action is thoroughly characterized through tensiometry, calorimetry and MD simulations. Secondly, the safety profiles are evaluated through cell-based in vitro assays. Ultimately, we could conclude that the alternative surfactants investigated possess a mode of action and safety profile comparable to polysorbates. Moreover, the biophysical patterns elucidated here can be exploited to precisely tune the features of future surfactant designs.

Not the Usual Suspects: Alternative Surfactants for Biopharmaceuticals

Therapeutically relevant proteins naturally adsorb to interfaces, causing aggregation which in turn potentially leads to numerous adverse consequences such as loss of activity or unwanted immunogenic reactions. Surfactants are ubiquitously used in biotherapeutics drug development to oppose interfacial stress, yet, the choice of the surfactant is extremely limited: to date, only polysorbates (PS20/80) and poloxamer 188 are used in commercial products. However, both surfactant families suffer from severe degradation and impurities of the raw material, which frequently increases the risk of particle generation, chemical protein degradation, and potential adverse immune reactions. Herein, we assessed a total of 40 suitable alternative surfactant candidates and subsequently performed a selection through a three-gate screening process employing four protein modalities encompassing six different formulations. The screening is based on short-term agitation-induced aggregation studies coupled to particle analysis and surface tension characterization, followed by long-term quiescence stability studies connected to protein purity measurements and particle analysis. The study concludes by assessing the surfactant's chemical and enzymatic degradation propensity. The candidates emerging from the screening are de novo α-tocopherol-derivatives named VEDG-2.2 and VEDS, produced ad hoc for this study. They display protein stabilization potential comparable or better than polysorbates together with an increased resistance to chemical and enzymatic degradation, thus representing valuable alternative surfactants for biotherapeutics.

An Intra-Company Analysis of Inherent Particles in Biologicals Shapes the Protein Particle Mitigation Strategy Across Development Stages

To better understand protein aggregation and inherent particle formation in the biologics pipeline at Novartis, a cross-functional team collected and analyzed historical protein particle issues. Inherent particle occurrences from the past 10 years were systematically captured in a protein particle database. Where the root cause was identified, a number of product attributes (such as development stage, process step, or protein format) were trended. Several key themes were revealed: 1) there was a higher propensity for inherent particle formation with non-mAbs than with mAbs; 2) the majority of particles were detected following manufacturing at scale, and were not predicted by the small-scale studies; 3) most issues were related to visible particles, followed by subvisible particles; 4) 50% of the issues were manufacturing related. These learnings became the foundation of a particle mitigation strategy across development and technical transfer, and resulted in a set of preventive actions. Overall, this study provides further insight into a recognized industry challenge and hopes to inspire the biopharmaceutical industry to transparently share their experiences with inherent particles formation.

Pharmacokinetics, biocompatibility and bioavailability of a controlled release monoclonal antibody formulation

The sustained and localized delivery of monoclonal antibodies has become highly relevant, because of the increasing number of investigated local delivery applications in recent years. As the local delivery of antibodies is associated with high technological hurdles, very few successful approaches have been reported in the literature so far. Alginate-based delivery systems were previously described as promising sustained release formulations for monoclonal antibodies (mAbs). In order to further investigate their applicability, a single-dose animal study was conducted to compare the biocompatibility, the pharmacokinetics and the bioavailability of a human monoclonal antibody liquid formulation with two alginate-based sustained delivery systems after subcutaneous administration in rats. 28 days after injection, the depot systems were still found in the subcutis of the animals. A calcium cross-linked alginate formulation, which was injected as a hydrogel, was present as multiple compartments separated by subcutaneous tissue. An in situ forming alginate formulation was recovered as a single compact and cohesive structure. It can be assumed that the multiple compartments of the hydrogel formulation led to almost identical pharmacokinetic profiles for all tested animals, whereas the compact nature of the in situ forming system resulted in large interindividual variations in pharmacokinetics. As compared to the liquid formulation the hydrogel formulations led to lower mAb serum levels, and the in situ forming system to a shift in the time to reach the maximum mAb serum concentration (Tmax) from 2 to 4 days. Importantly, it was shown that after 28 days only marginal amounts of residual mAb were present in the alginate matrix and in the tissue at the injection site indicating nearly complete release. In line with this finding, systemic drug bioavailability was not affected by using the controlled release systems. This study successfully demonstrates the suitability and underlines the potential of polyanionic systems for local and controlled mAb delivery.

Protein stabilization by cyclodextrins in the liquid and dried state

Aggregation is arguably the biggest challenge for the development of stable formulations and robust manufacturing processes of therapeutic proteins. In search of novel excipients inhibiting protein aggregation, cyclodextrins and their derivatives have been under examination for use in parenteral protein products since more than 20 years and significant research work has been accomplished highlighting the great potential of cyclodextrins as stabilizers of therapeutic proteins. Oftentimes, the potential of cyclodextrins to inhibit protein aggregation has been attributed to their capability to incorporate hydrophobic residues on aggregation-prone proteins or on their partially unfolded intermediates into the hydrophobic cavity. In addition, also other mechanisms besides or even instead of complex formation play a role in the stabilization mechanism, e.g. non-ionic surfactant-like effects. In this review a comprehensive overview of the available research work on the beneficial use of cyclodextrins and their derivatives in protein formulations, liquid as well as dried, is provided. The mechanisms of stabilization against different kinds of stress conditions, such as thermal or surface-induced, are discussed in detail.