problem when cleaning a query

[eluser]ahmedi[/eluser]
I have a blocking problem with an sql query , here is my code
$term = $this->db->escape($tag);
$request = "SELECT * from tags WHERE tag REGEXP '[[:<:]]".$term."(s|es)*$'";

When this query is executed i obtain form example for $tag='test' ;

$request = "SELECT * from tags WHERE tag REGEXP '[[:<:]]'test'(s|es)*$'";
which is not good because i have quotes around test word, how can i avoid this probelme
thanks