$re = '/\b(?i)m[^A-Za-z0-9]*e[^A-Za-z0-9]*d[^A-Za-z0-9]*i[^A-Za-z0-9]*a[^A-Za-z0-9]*t[^A-Za-z0-9]*i[^A-Za-z0-9]*z[^A-Za-z0-9]*e\b/m';
$str = 'mediatize
m_e_d_i_a_t_i_z_e
m e d i a t i z e
m__e__d__i__a__t__i__z__e
m·e·d·i·a·t·i·z·e
MEDIATIZE
M_E_D_I_A_t_i_z_e
';
preg_match_all($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