Introduction
Squalene is a natural organic molecule that plays an important role in various industries, including pharmaceuticals. In the healthcare sector, it is particularly valued for its use in parenteral drug delivery products as a component in adjuvant systems, such as in inactivated vaccines like the influenza vaccine. Adjuvants are added to vaccines to make them more effective at inducing immunity. Traditionally, the primary source of pharmaceutical-grade squalene has been shark liver oil, which, while effective, raises environmental, quality and ethical concerns.
The challenges of using animal-based squalene
Many shark species are listed as endangered, so hunting sharks for squalene makes the situation worse. Shark population depletion also damages the overall ecosystem, resulting in loss of marine biodiversity.
From a quality perspective, animal-derived squalene can also have batch-to-batch variability, which can make regulatory approval of pharmaceutical products containing animal-derived squalene more challenging. In addition, many sharks are highly contaminated with methylmercury, a bio accumulative environmental toxin that can damage the nervous system. This contamination poses a risk when using animal-derived squalene in pharmaceuticals.
There are also cultural and religious reasons that may prevent certain patient groups from using animal-based products, which may limit the accessibility and acceptance of medicines containing animal-derived squalene.
PhytoSquene® - the world’s first plant-based GMP squalene
To offer an alternative to animal-derived squalene, Evonik has developed the plant-derived squalene PhytoSquene® for pharmaceutical applications.
Manufacturing PhytoSquene®
PhytoSquene® is produced from amaranth (Amaranthus caudatus) seed oil, using a process that combines upstream clarification with a chromatographic technique, ensuring economic efficiency and high-purity squalene (99-100%). Manufactured under GMP standards, it meets the pharmaceutical industry's stringent demands, including European Pharmacopoeia (Ph. Eur.) compliance.
Comparability studies with PhytoSquene®
Evonik conducted a study to compare the physical chemical attributes and in vitro toxicity effect of GMP-grade PhytoSquene® with traditional animal-derived squalene, aiming to confirm PhytoSquene® as a sustainable alternative for adjuvants. The study was based on a well-known adjuvant system formulated as an oil-in-water emulsion model (similar to MF59) and included physicochemical assessments and in vitro toxicity tests to draw comparisons.
Both plant-based and animal-based squalene were formulated into oil-in-water emulsions, each comprising 4.3% squalene, 0.5% Tween 80, and 0.5% Span 85 as non-ionic emulsifiers, with a citrate buffer as the aqueous phase. The emulsions were analyzed for particle size and polydispersity index (PDI), pH, osmolality, and viscosity, and compared to a commercial adjuvant. Additionally, the study included an MTS assay using a T-cell-derived cell line to evaluate the in vitro toxicity of the adjuvant formulations.
Results showed that adjuvants with either plant-derived or shark-derived squalene shared similar characteristics. The particle size and polydispersity index (Figure 1) were on par with the marketed product. Other properties including appearance, osmolality, viscosity, pH and zeta potential were also aligned closely with the marketed formulation (Table 1).
Figure 1: Particle size (Z-average) and polydispersity index (PDI) of various squalene emulsions using dynamic light scattering (DLS). Characterization study shows no significant differences between shark squalene and PhytoSquene® emulsions in terms of particle size and PDI. A commercially available shark squalene adjuvant formulation was used as a control.
Table 1: Squalene emulsion physical properties
Other characterizations that were measured to compare the formulations. A commercially available shark squalene adjuvant formulation was used as a control.
In vitro testing revealed that the non-animal and shark-derived squalene adjuvant formulations were non-toxic to cells under the applied conditions (Figure 2). This study points to the potential of PhytoSquene® as a viable and environmentally friendly alternative to traditional squalene, with similar safety profiles.
A)
B)
Figure 2: A) Emulsions indicate no cytotoxic impact on the cell viability within the in vitro test (ratios reported in v/v). B) Excipients demonstrate no significant effect on the in vitro cell viability. The threshold is defined as 70% cell viability compared to the control, therefore values above 70% indicate cytocompatibility under the applied conditions.
Sustainability and quality benefits of PhytoSquene®
Evonik supports 12 UN Sustainable Development Goals (SDGs) relevant to its operations. PhytoSquene® offers an alternative to shark-derived squalene, aiding ecosystem protection and health. It guarantees consistent quality, meeting European Pharmacopoeia standards, essential for pharmaceutical effectiveness and safety. Additionally, PhytoSquene® caters to those avoiding animal products due to cultural or religious beliefs, enhancing patient accessibility and acceptance for squalene-containing medicines.
Conclusion
By incorporating PhytoSquene® into pharmaceutical products, companies can create drug products that not only promote a healthy life but also contribute to a more sustainable and responsible industry. Comparability studies with PhytoSquene® and commercially available shark-derived squalene show that both have comparable physicochemical properties and in vitro toxicology profiles. This parenteral drug delivery innovation demonstrates how plant-based solutions can replace animal-derived materials without compromising efficacy, paving the way for a more sustainable and inclusive future in healthcare.
Learn more: https://evonik.click/phytosquene-plant-based-squalene