my               $content1=''&#22 x';
                 $content1=~s/\&(\#\d*[^;\d]+)/\&$1/gs; 
print '1:'.$content1."\n"; 

my               $content2=''&#22 x';
                 $content2=~s/\&(\#\d*[^;]+)/\&$1/gs; 
print '2:'.$content2."\n"; 


##</code><code>##

1:&#39;&amp;#22 x
2:&amp;#39;&amp;#22 x


##</code><code>##

This is perl 5, version 20, subversion 1 (v5.20.1) built for MSWin32-x86-multi-thread-64int
(with 1 registered patch, see perl -V for more detail)

Copyright 1987-2014, Larry Wall

Binary build 2000 [298557] provided by ActiveState http://www.ActiveState.com
Built Oct 15 2014 22:10:49