$re = '/:\s*([^,]+)/';
$str = 'It sent a notice of delivery of goods: UserName1 (00215478),UserName2 (00258747)
Sent a notice of delivery of the goods: User is not found, UserName2 (00258747)
It sent a notice of receipt of the goods: UserName1 (00215478),UserName2 (00258747)
It sent a notice of receipt of the goods: User is not found, UserName2 (00258747)';
preg_match_all($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