Ben Eastick Written by Ben Eastick

Sugar in vaccines: stabilising and preserving effectiveness

As the number of UK adults receiving their first coronavirus vaccine dose continues to grow, over 28 million at last count, we explain the vital role sugar plays in keeping these vaccines effective. A spoonful of sugar really does help the medicine go down.

Doctor or nurse administering covid-19 vaccine with injection needle in the arm of a man both in full PPE

The UK aims to have offered all adults a first dose of a COVID-19 vaccine by the close of July. 

Racing to develop safe and effective vaccines

When initial reports of the disease appeared in late 2019, few could have imagined the tragedy to come. Once the threat the COVID-19 virus poses to life, and livelihoods, became clear, the world raced to develop and deploy safe and effective vaccines to stop its spread.

Vaccines save an estimated 2-3 million lives every year and prevent the health impacts of bacterial and viral diseases that may not be fatal but still have harmful long-term and often debilitating impacts. Vaccines work by preparing the body’s defences to recognise and fight off viruses and bacteria.

By exposing the body to a weaker form of the virus, the immune system is trained to create the antibodies to fight it. Following vaccination, if the body is later exposed to the microorganism, the immune system is ready to destroy them with antibodies, either preventing the individual from experiencing illness or weakening the effect of the disease.

Vaccines underpin the public health response to protect the population from the COVID-19 coronavirus. The typical development cycle of a vaccine is ten to fifteen years. This means developing multiple COVID-19 vaccines in approximately 12 months is an exceptional achievement.

A spoonful of sugar does a whole lot more than help medicine go down

We’re going to explore three of the vaccines developed over the past year and approved for use in the UK – AstraZeneca, Pfizer-BioNTech and Moderna. Apart from the obvious – training your body to fight against COVID-19 – there is an ingredient they all share – sugar.

Sugar is used as an excipient in many medicines, not just vaccines. An excipient is an inactive substance that acts as the dosage vehicle for an active drug. They are a vital part of the drug delivery mechanism as they stabilise the active ingredient so the medicine can be stored and transported without going out of date or losing its efficacy. Excipients are also used to bulk up medicines so they can more easily be used or taken by patients. This could, for example, mean formulating liquids to be injected or tablets for oral delivery. Excipients may also be used to ensure the active ingredient can perform its role properly, such as slowing active ingredient release time. Finally, an excipient such as sugar adds taste and texture to orally administered medicines.

The AstraZeneca, or AZ, vaccine’s contains polysorbate 80, L-histidine, L-histidine hydrochloride monohydrate, magnesium chloride hexahydrate, polysorbate 80, ethanol, sucrose, sodium chloride, disodium edetate dihydrate and water.

The Pfizer-BioNTech vaccine includes the following ingredients: messenger ribonucleic acid (mRNA), lipids ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate), 2 [(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-Distearoyl-sn-glycero-3- phosphocholine, and cholesterol), potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodium phosphate dihydrate, and sucrose.

The Moderna vaccine contains the following ingredients: mRNA, lipids (SM-102, polyethylene glycol [PEG] 2000 dimyristoyl glycerol [DMG], cholesterol, and 1,2-distearoyl-sn-glycero-3-phosphocholine [DSPC]), tromethamine, tromethamine hydrochloride, acetic acid, sodium acetate, and sucrose.

Why sugar is an excipient in vaccines

As vaccines are biological preparations, they can be unstable once created, some more than others. This instability can reduce the safety and efficacy of the biological product. Vaccines can also be sensitive to heat, light, or changes in the environment.

Sugar acts as a stabiliser due to its natural humectant properties. Within the food and beverage industry it is used as a multifunction product for this very reason, it not only sweetens food, but also helps food stay fresh and maintain its moisture. And in the pharmaceutical industry, sugar keeps the vaccine effective by stopping the molecules from losing their shape in the manufacturing process, storage, distribution and eventually when administered to patients.

Even with stabilisers, vaccines typically require refrigeration and may have a short-shelf life. For example, the Pfizer-BioNTech requires storing in a freezer at -80 °C to -60 °C. Indeed, in the UK, vaccination centres often ‘search’ for patients to administer ‘spare vaccines’ to after patients with scheduled appointments have failed to turn up. They do this so they do not waste any vaccines after they have been distributed to the vaccine centre for that specific day, because the vaccine will not remain effective if administered beyond a specific time.

Temperature controlled covid-19 vaccines held by scientist in full PPE

Many types of vaccines must be stored and transported at freezing temperatures to remain effective.

Which sugar products can be used in vaccines?

Excipients are as tightly regulated as the active ingredients. Only specific types of sugar can be used for vaccines meeting specific regulatory requirements to be of a pharmaceutical grade. Two sugars used in vaccine production are pharma grade sucrose – a crystalline powder – and pharma grade invert sugar syrup.

The most effective humectants are pure sugars. As vaccines contain such small quantities of stabilisers, they need these stabilisers to have optimal performance – therefore invert sugar syrup is the ideal stabilising ingredient. Sugar products also come with the added benefit of being significantly better value than synthetic alternatives.

Unsurprisingly, the wider global population has become increasingly aware of the challenges of vaccine manufacture and supply chain logistics. This is particularly true in the UK, with its departure from the European Union highlighting further cross border challenges. Now more than ever, it is important to realise that high-quality, consistent and reliable pure sugar products are a key part of the solution for bulk manufacturers across a range of industries.

We need to celebrate the role pure sugars play in the pharmaceutical industry. Without high quality, natural sugar products, large-scale manufacture and deployment would not be as effective or efficient.

Ragus manufactures specialist pure sugars for the pharmaceutical industry, ensuring your pharmaceutical grade sugar benefits from our dedicated approach to quality, consistency and on-time delivery. To learn how we can help you you’re your unique industry challenges, contact a member of our customer services team on +44 (0)1753 575353 or today. For more sugar news and Ragus updates, follow Ragus on LinkedIn.