Search results that do not contain a word

[mtxpert]

I tried for an hour but couldn't find the answer. I need to search my syslogs from a specific host for entries that do not contain the word Interface my current search line is:

sourcetype="cisco_syslog" host="10.10.10.10"

I tried

sourcetype="cisco_syslog" host="10.10.10.10" | regex _raw(=|!=) [\ )?Interface(\] 

but it doesn't work.

I'm sure I'm close but I am terrible at regular expressions.

[gkanapathy]

sourcetype="cisco_syslog" host="10.10.10.10" NOT "interface"

http://www.splunk.com/base/Documentation/latest/User/StartSearching#Add_Boolean_expressions