TREATMENT OF ALUMINUM HYDROXIDE ADJUVANT TO OPTIMIZE THE ADSORPTION OF BASIC-PROTEINS

Aluminium hydroxide adjuvant has an isoelectric point (i.e.p) of ca 11 and is a good adsorbent for acidic proteins due to the contribution o f electrostatic attractive forces. However, electrostatic repulsive fo rces reduces its ability to adsorb basic proteins. Pretreatment of alu minium hydroxide adjuvant with carefully selected concentrations of ph osphate anion reduces the positive surface charge which exists at pH 7 .4. Treatment with higher concentrations of phosphate anion produces a negative surface charge. The adsorption of lysozyme (i.e.p. = 11.1) w as found to be directly related to the concentration of phosphate anio n used to pretreat the aluminium hydroxide adjuvant. Copyright (C) 199 6 Elsevier Science Ltd.