$re = '/(\B(".+?")\B|\B(\'.+?\')\B|\B(`.+?`)\B)/m';
$str = '"Lorem ipsum dolor sit amet", consectetur adipisicing elit, "\'sed do eiusmod tempor,\'" incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, `quis nostrud` exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. `Duis aute irure dolor` in "reprehenderit in voluptate" velit esse cillum \'dolore eu fugiat nulla\' pariatur. ';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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