m!(\d+).+to.+(\d+)!i

##</code><code>##

  123to456

##</code><code>##

  (12)3to45(6)
   $1       $2

##</code><code>##

  m!(\d+)\D+to\D+(\d+)!i;

##</code><code>##

  m!(\d+)\D*?to\D*?(\d+)!i;