Marketed formulations of extended phenytoin sodium -- long a difficult medication to titrate because of its unique absorption and saturable elimination pharmacokinetics -- may not be bioequivalent ...

making 1% or more of the HA nonionized form (e.g., phenytoin sodium in 5% dextrose injection). The pH values of -ium or -ium and -ate salt injections are usually greater, less acidic, or more ...