<?php

function DbrecordEsist($title) {

    // hier moet een query komen die controleert of er al een db record is met deze tweet

}

function filterTitle($title) {

    $titleParts = explode(":", $title);

    unset($titleParts);

    $title = implode(":", $title);
    $title = trim($title);

    $haystacks = array();
    $replacements = array();

    $title = str_replace($haystacks, $replacements, $title);

    return $title;

}

$urls = array('https://api.twitter.com/1/statuses/user_timeline.rss?screen_name=xmeidenmode');

foreach($urls as $url) {

    $data = simplexml_load_file($url);

    foreach($data->channel->item as $key => $item) {

        $title = filterTitle($item->title);

        if(!DBrecordExist($title)) {

            // hier komt de insert query

        }
    }

}