samin

<?php

$string = "Lorem ipsum dolor sit amet, <a href=\"#\">consectetuer adipiscing</a> elit, <strong>tincidunt</strong> ut volutpat.";

$content = "";
$words = preg_split('/\s+/', trim($string));
foreach ($words as $word) {
    $content .= '<span>'.$word.'</span>';
}