how's the corect expression of preg_split, to split a string that starts with class and i want to end when word client is found? -  preg_split("/class+{*}+client&/","class some data here lala client cucu yes 123"); is not working

$pattern = "@^class.*client@s";
$string = "class some data here lall client wtf";
$array = preg_split($pattern,$string);