The World Health Organisation recommends adsorption of 80% or more of tetanus and diphtheria toxoid antigens by aluminium containing adjuvants. The protein adsorption capacities from aluminium and calcium adjuvants are well documented. Modified Allergen Tyrosine Adsorbed-Monophosphoryl Lipid A (MATA-MPL) formulations have been shown to be effective therapeutics in allergy immunotherapy. The micro crystalline tyrosine (MCT) in these formulations has been shown to consistently adsorb both allergoid and MPL on manufacture. However MCT adsorption capacity factors for proteins and MPL have not been measured for direct comparison to aluminium and calcium adjuvants.
Adsorption capacities of MCT for MPL and protein were calculated from quantitative determinations of both in the formulations. A gas chromatography method was used to determine MPL contents and a Bradford method was used to determine protein contents. Adsorption capacities of aluminium and calcium adjuvants were calculated in a similar way for direct comparison to MCT.
MCT demonstrated greater adsorption capacities for MPL than both aluminium and calcium adjuvants
The ability of MCT to readily adsorb MPL compared to aluminium and calcium adjuvants supports a characteristic association based on both tyrosine’s structure and MCT’s physical properties. MCT is an effective depot candidate for allergy immunotherapy formulations and vaccines.