Elastomeric polymers and compounded elastomers have reduced amounts of leachables. The compound comprises a polymer and 50 to 100 phr of filler. The polymer is prepared by reacting a mixture of i) a C4 to C7 isoolefin monomer, ii) a styrene based monomer, and optionally iii) a C4 to C14 multiolefin monomer wherein the polymer contains 5 to 15 wt % of styrene derived units. At least 5% of the filler is precipitated silica.