$re = '/<b>(.*?)<\/b>(.*?)(?=<b>|$)/m';
$str = '<b>Title1:</b><br/><b>Title2:</b> Value1<br/><b>Title3:</b> Value2<br/><b>Title4:</b> Value3<br/>Value4<b>Title5:</b> Value5<br/>';
preg_match_all($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