Mineral-based adjuvants

A number of mineral-based substances display an adjuvant effect. Although calcium phosphate, calcium chloride and salts of various metals (e.g. zinc sulfate and cerium nitrate) display some effect, aluminium-based substances are by far the most potent. Most commonly employed are aluminium hydroxide and aluminium phosphate (Table 13.13). Their adjuvanticity, coupled to their proven safety, render them particularly valuable in the preparation of vaccines for young children. They have been incorporated into millions of doses of such vaccine products so far. 

Various additional oil-based adjuvants have subsequently been developed. Adjuvant 65, for example, consists of 86% peanut oil, 10% Arlacel A and 4% aluminium monostearate (as a stabilizer). Unlike mineral oil, peanut oil is composed largely of triglycerides, which are readily metabolized by the body. Although adjuvant 65 was initially proved safe and effective in humans, it displayed less adjuventicity than FIA. Its use was largely discontinued, mainly due to the presence in its formulation of Arlacel A. 

Montanides Montanides are a group of oil/surfactant based adjuvants in which different surfactants are combined with a non-metaboKsable mineral oil, a metabolisable oil, or a mixture of the two. They are prepared for use as an emulsion with aqueous antigen solution. The surfactant for e.g. Montanide ISA 50 (ISA = Incomplete Seppic Adjuvant) is mannide oleate, a major component of the surfactant in Freund s adjuvants. The various Montanide ISA group of adjuvants are used as water-in-oil emulsions, oil-in-water emulsions, or water-in-oil-in-water emulsions. 

The stability of vaccines was enhanced in several ways against destabilizing solvents and polymers. By careful selection of the PLGA copolymer composition and molecular weight, an oil (mineral oil)-based cores of tetanus toxoid surrounded by outer polymer shells (PLGA) potentially protecting the bioactive material against water-mediated inactivation processes. However, adjuvants such as trehalose, threonyl muramyl dipeptide, " BSA, - and PEG 400 can also be used for this purpose. 

Hilgers LA, Platenburg PL, Luitjens A, Groenveld B, Dazelle T, Ferrari-Laloux M, Weststrate MW. 1994a. A novel non-mineral oil-based adjuvant. I. Efficacy of a synthetic snlfohpopolysaccharide in a squalane-in-water emukion in laboratory animak. Vaccine 12(7) 653-660. 

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