The Collaborative International Dictionary of English v.0.48:

Dissolvable \Dis*solv"a*ble\, a. [From Dissolve, cf.
   Dissoluble.]
   Capable of being dissolved, or separated into component
   parts; capable of being liquefied; soluble. --
   Dis*solv"a*ble*ness, n.
   [1913 Webster]

         Though everything which is compacted be in its own
         nature dissolvable.                      --Cudworth.
   [1913 Webster]

         Such things as are not dissolvable by the moisture of
         the tongue.                              --Sir I.
                                                  Newton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dissolvable
    adj 1: capable of dissolving [syn: dissolvable, dissoluble]