Vaccine Adjuvants

26 Haziran 2020

Croda has been a specialised and leading supplier of vaccine adjuvants since 1939 dedicated to consistent high quality and outstanding manufacturing capabilities. Croda is the only adjuvant supplier in the world with an aseptic and GMP certified manufacturing site for vaccine adjuvants.

For more than 80 years our vaccine adjuvant business has been dedicated to safe and effective adjuvants suitable for use in both human and veterinary vaccines. To this day, our focus has been to successfully develop, manufacture and market high-quality adjuvants for our pharmaceutical customers. Our industry-leading, Alhydrogel®, Adju-Phos®, Quil-A®, and QS-21® are widely recognised in the vaccine industry for their unmatched track record when it comes to a proven history of safe and effective use.

An adjuvant is a substance which is added to a vaccine with the aim of increasing the efficiency of that vaccine. From a chemical point of view, adjuvants are a highly heterogeneous group of compounds that share only one functional characteristic: That of being able to enhance immune responses. The most commonly used adjuvants are: Aluminium hydroxide, aluminium phosphate, oil emulsions and purified quillaja saponin.

Adjuvants are used in vaccine production to stimulate the immune system and raise an early, long-lasting and efficient immune response to the vaccine. This increases efficacy and provides a high degree of protection from the disease against which you are vaccinating. By using adjuvants you will reach the same level of immune protection using fewer injections than when vaccinating with the non-adjuvanted antigen.

Adjuvant Categories Our range of adjuvants is most easily categorised by chemically grouping the components used in the final product.


Mineral-Based Adjuvants

Aluminium adjuvants have been used in vaccines for more than half a century to induce early, high-titre, long-lasting protective immunity. Billions of doses of aluminium-adjuvanted vaccines have been administered over these years and they are, at present, the most widely used adjuvants in both veterinary and human vaccines.

• Alhydrogel – Aluminium Hydroxide Gel Alhydrogel is a range of aluminium hydroxide gel products which have been specifically developed for use as an adjuvant in human and veterinary vaccines. The gel is a suspension of boehmite-like (aluminium oxyhydroxide) hydrated nano/micron size crystals in loose aggregates. The products have a very low conductivity as a result of the proprietary production process.

Alhydrogel products have a positive charge at neutral pH and effectively adsorb negatively charged antigens. The primary purpose of the adjuvant in vaccines is to boost the antibody-mediated (Th2) immune response to the antigens. Alhydrogel products can be combined with other adjuvants types (such as MPL – Monophosphoryl Lipid) to achieve a balanced Th1/Th2 immune response.


Alhydrogel is supplied in concentrations of either 6.5 mg/ml or 10 mg/ ml aluminium. A premium version (Alhydrogel “85”) with approximately 20% higher protein adsorption capacity is also available.

• Adju-Phos – Aluminium Phosphate Gel Adju-Phos is a range of aluminium phosphate gel products which have been specifically developed for use as adjuvants in vaccines. The gel is a suspension of hydrated amorphous aluminium hydroxyphosphate nano/micron size particles.

Adju-Phos products have a net negative charge at neutral pH and effectively adsorb positively charged antigens. The primary purpose of the adjuvant in vaccines is to boost the antibody-mediated (Th2) immune response to the antigens. Adju-Phos products can be combined with other adjuvant types (such as MPL) to achieve a balanced Th1/Th2 immune response.

Adju-Phos is supplied in two variants with pH-values at ~6.5 and at ~5.0. Both variants contain 0.9% NaCl (saline) to reduce injection site discomfort.

Saponins Purified Quillaja saponin is a widely-used adjuvant for veterinary applications. Our product, Quil-A®, can be used alone or combined with cholesterol, phosphatidylcholine and amphipathic antigens to forms ISCOMs. To complete our product offering in this area, our newest adjuvant QS-21 is a purified triterpenoid saponin for use in human vaccines. QS-21 has been shown to enhance antibody- and cell-mediated immune response and has been investigated and found appropriate for use in human vaccines.

• Quil-A – Quillaja Saponin Vaccine Adjuvant

Quil-A is a highly purified quillaja saponin product which has been specifically developed for use as an adjuvant in vaccines. Quil-A saponin was originally purified and characterised by Dr. Pharm. Kristian Dalsgaard in 1974 and adapted for commercial scale production in cooperation with Croda.

Quil-A consists of a complex mixture of ca. 25 different saponin molecules which have the triterpenoid backbone in common. It is a very versatile adjuvant due to its ability to induce a balanced immune response to protect against both intracellular (Th1) and extracellular (Th2) pathogens.

Quil-A saponin has the ability to form cage-like immunostimulating complex (ISCOM) particles together with cholesterol and phospholipids which can further increase the potency of the adjuvant and reduce local reactogenicity. Furthermore, novel nanoparticle adjuvants containing quillaja saponin as the active component are currently being developed.

Quil-A is supplied as a water-soluble lyophilised powder with minimum 95% dry matter. The product has been sterile-filtered prior to lyophilisation to ensure a low bioburden in the final product and has a long shelf life.

• QS-21 – Saponin Fraction from the Bark of Quillaja Saponaria Molina

QS-21 is a defined molecule of the triterpenoid saponin fraction extracted from the bark of the South American tree, Quillaja saponaria Molina. QS-21 is a water-soluble triterpenoid glycoside with amphiphilic character and the QS-21 fraction largely comprises a mixture of two isomeric components. “QS” denotes the source, Quillaja saponaria, and “21” denotes the identity of the RP-HPLC peak.

QS-21, has been shown to enhance antibody- and cell-mediated immune response and has been developed for human vaccine applications. It was originally isolated by Dr. Charlotte Kensil in 1991 and among the components of triterpenoid quillaja saponins, QS-21 possesses an optimal balance of low toxicity and high immunostimulatory efficacy. QS-21 is one of the most potent immunological adjuvants that has been widely used. Vaccines containing QS-21 are now commercially available and used to prevent diseases such as malaria, which it was previously not possible to develop effective vaccines against. Because of its broad activation of the adaptive immune system, QS-21 is considered a candidate adjuvant for many current trial vaccines (such as phase 2 and phase 3 studies of hepatitis B, HIV-1 and cancer), in which other vaccine adjuvants have shown less promising results.


Selce Küçükbayrak

Sales Representative – Black Sea, Israel & Greece
Croda Kimya Tic. Ltd. Şti.