Safe data from database

[eluser]Jagar[/eluser]
The site is on intranet, and not many people will be using it, but there are stupid people who will mess with it and will do anything to crash it.

I have a form(not used form helper), it adds certain data, so I was inserting the weirdest strings I could think of such as

Code:

[removed]

something like that, using the mysql_real_escape_string function it will only escape the double code. So I asking for a way to insert the data safely into the database which does it, and then retrieve it for display, I found htmlspecialchar function and htmlentities function which does the job, is there better way than using those functions in CI?

Thanks!