aluminium phosphate adjuvant

Aluminium phosphate adjuvant is an amorphous, non-crystalline aluminum salt used primarily as a **vaccine adjuvant** in human and veterinary vaccines to enhance immune responses, especially humoral (antibody-mediated, Th2) responses[1][2][4][5]. It consists mainly of hydrated aluminium hydroxyphosphate with variable P:Al ratios, typically forming negatively charged plate-like particles suspended in a wet gel. Its mechanism involves: - **Depot effect** (retaining antigens at the injection site for prolonged presentation) - **Phagocytosis enhancement** (improved uptake of antigen by antigen-presenting cells) - **Activation of innate immune pathways**, including NLRP3 inflammasome and pro-inflammatory signaling[2][4] - **Complement cascade activation**, promoting immune cell recruitment[4] It is commonly used in DTP (diphtheria, tetanus, pertussis), hepatitis B, polio, and Hib vaccines[1][5]. Commercially available under the brand name Adju-Phos, it is produced to pharmaceutical standards, with sterility and pyrogenicity controls[1]. Compared to aluminum hydroxide adjuvants (Alhydrogel), Adju-Phos has a lower point of zero charge, meaning it is negatively charged at physiological pH and thus optimal for positively charged antigens[1][4].

Brand names

Adju-Phos

Other names

aluminium phosphatealuminum phosphate adjuvantaluminium phosphate gelaluminium hydroxyphosphate