slightly edited the query from msdn, hopefully will help you out:

DECLARE @IntVariable varchar(10);

DECLARE @SQLString nvarchar(500);

DECLARE @ParmDefinition nvarchar(500);

SET @IntVariable = 'somevalue';

SET @SQLString = N'SELECT *

FROM [database].dbo.

WHERE [field] = @level';

SET @ParmDefinition = N'@level varchar(10)';

EXECUTE sp_executesql @SQLString, @ParmDefinition, @level = @IntVariable;