$re = '/(?<=>Expires at:<\/label>\n<div class=\"col-md-9\">\n<p class=\"form-control-static\">\n)([ \w,]*?)\s*</m';
$str = '<div class="col-md-6">
<div class="form-group">
<label class="control-label col-md-3">Expires at:</label>
<div class="col-md-9">
<p class="form-control-static">
March 3rd, 2019 </p>
</div>';
preg_match_all($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