preg_replace specific Text to small latter strtolower [closed]

function emailleftappend($content){


    $content = preg_replace_callback('/(?<=get\/)(.*?)-(.*?)(?=\/">)/', function ($m) {
  return sanitize_title($m[1]). '-'. sanitize_title($m[2]); }, $content);

    return $content;
}
add_filter('the_content', 'emailleftappend');

the above fixed the issue for me. another way is below.

function emailleftappend($content){

        $content = preg_replace_callback('/(?<=get\/)(.*?)-(.*?)(?=\/">)/', function ($m) {
      return slug($m[1]). '-'. slug($m[2]); }, $content);

        return $content;
    }
    add_filter('the_content', 'emailleftappend');

function slug($z){
    $z = strtolower($z);
    $z = preg_replace('/[^a-z0-9 -]+/', '', $z);
    $z = str_replace(' ', '-', $z);
    return trim($z, '-');
}

FINALLY FIXED