$re = '/^([a-zA-Z][\s\S]*?)\<br\>/im';
$str = 'Лорем ипсум<br>привет мир<br>голактеко опасносте<br>Лорем ипсум<br>
Lorem ipsum dolor <a href="">sit</a> amet, consectetur adipisicing elit.<br>
<br>
<img src="img.jpg" alt="">
<br>
Lorem ipsum dolor sit amet, consectetur <a href="">adipisicing</a> elit.<br>
<br>
<div class="inner">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Impedit, voluptas.</div>
<br>
Lorem ipsum <span>dolor</span> sit amet, consectetur adipisicing elit.<br>
<br>
<div>
<img src="img.jpg" alt="">
</div>
<br>
Lorem <b>ipsum</b> dolor sit amet, consectetur adipisicing elit.<br>
<br>
<div>Lorem...</div>
<br>
Lorem ipsum dolor sit amet, consectetur adipisicing elit.<br>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php