$re = '/(\d+)(?!.*\1)/s';
$str = '"/manufacturers/244/rz-xvxcv/images/swed"
"/manufacturers/23/rz-gf/images/sltn"
"/manufacturers/34/rz-dffdf/images/five"
"/manufacturers/23/rz-gfgf/images/lead"
"/manufacturers/322/rz-dfg/images/carr"
"/manufacturers/3789/rz-fgdfgfg/images/zing"';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php