Stability of aluminium-containing adjuvants to autoclaving.
Aluminium phosphate adjuvant remained amorphous when autoclaved for 30 or 60 min at 121 degrees C. However, deprotonation and dehydration reactions occurred as evidenced by a decrease in the pH. The protein adsorption capacity, rate of acid neutralization at pH 2.5 and point of zero charge also decreased indicating that the deprotonation/dehydration reactions resulted in a decreased surface area. Autoclaving aluminium hydroxide adjuvant increased the degree of crystallinity as measured by the width at half height of the major band in the X-ray diffractogram. The pH decreased during autoclaving suggesting that the same deprotonation/dehydration reactions which reduced the surface area of aluminium phosphate adjuvant were responsible for the increased degree of crystallinity. These reactions also resulted in a reduced surface area as both the protein adsorption capacity and viscosity decreased following autoclaving.
Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907, USA.
L S
LS
Burrell
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EB
Lindblad
J L
JL
White
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Hem
D000276:Adjuvants, Immunologic / Q000737:chemistry*; D017607:Aluminum Compounds / Q000737:chemistry*; D000536:Aluminum Hydroxide / Q000737:chemistry*; D004355:Drug Stability; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D010710:Phosphates / Q000737:chemistry*; D014961:X-Ray Diffraction
D000276:Adjuvants, Immunologic; D017607:Aluminum Compounds; D010710:Phosphates; D000536:Aluminum Hydroxide; C012714:aluminum phosphate