$re = '/^(U)(AA|AB|BA|BB|CC|CD|EA|FA|GA|HA|IA|JA|AE|CE|GE|FB|JB|GB|HL|IL|JL)(E|U|W)(E)(DN|AZ)(\d{2,2})(\d)(\d{8,8})$/i';
$str = 'UCCUEDN15000003676';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($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