The Collaborative International Dictionary of English v.0.48:

Antalkali \Ant*al"ka*li\ (?; 277), Antalkaline \Ant*al"ka*line\,
   n. [Pref. anti- + alkali.]
   Anything that neutralizes, or that counteracts an alkaline
   tendency in the system. --Hooper.
   [1913 Webster]