PHP Regular expression for star '*'

Question

I have a string ending with '*' or '^'.
For example:

$variable = 'abcdef**^^';

I used preg_split() function to split the string.

$variable = 'abcdef*^^^^';
$words = preg_split("/(?<=\w)\b[!?.]*/", $variable, -1, PREG_SPLIT_NO_EMPTY);

And I got the output as

Array
(
    [0] => abcdef
    [1] => *^^^^
)

But the problem begins, when my variable is replaced with '@','' and some other special characters.
For Example:

$variable = 'abc@d ef*^^^';  

Output become like this

Array
(
    [0] => abcd
    [1] => @ ef
    [2] => *^^^^
)

I need the output like this

Array
(
    [0] => abcd@ ef
    [1] => *^^^^
)

I was trying to replace my current RegEx with RegEx for '*' and '^', But I can't find one.

Answer 1

Thank you for all your answers.
I have figured my solution by the references you all given.
I am posting it,May help anyone in future..

<?php

$variable = 'Chloride TDS';
if (preg_match('/[\*^]/', $variable))
{
if ( strpos( $variable, '*' ) < strpos( $variable, '^' )   || strpos( $variable, '^' ) === false ) 
{
    $first = strstr($variable, '*', true);

    $last = strstr($variable, '*');
}

if ( strpos( $variable, '^' ) < strpos( $variable, '*' ) && strpos($variable,'^') != '' || strpos( $variable, '*' ) === false ) 
{
    $first = strstr($variable, '^', true);
    $last = strstr($variable, '^');
}
echo $first;
echo '<br/>';
echo $last;
}else{
    echo $variable;
}



?>