<?php

$url = 'http://e...content-available-to-author-only...e.com?param=test1\test2\test3\test4';
$cleanUrl = preg_replace('|[^-\\\\a-z0-9~+_.?\[\]^#=!&;,/:%@$\|*`\'<>"()\x80-\xff{}]|i', '', $url);
echo $cleanUrl;