<?php
$url = 'administracion.php?modAdministracion=administracio n&bajaCliente=bajaCliente';
$tokens = explode("&", $url);
$key = "bajaCliente=bajaCliente";
$text = '';
foreach($tokens as $token) {
if ($token !== $key) {
$text .= $token;
}
}
$url = $text;
echo $url;
<?php
$url = 'administracion.php?modAdministracion=administracio n&bajaCliente=bajaCliente';
$parse=parse_url($url);
echo $parse["path"];
?>