In Antigone, what are Creon's principles?

Interesting question. By "principles," I assume you are
referring to his values or morales which dictate how he acts and what he says and does.
One of Creon's first speeches directly refers to his "principles," which also explains
why he has refused to allow the body of Polynices to receive proper burial. Note what he
says:

These
are my principles. Never at my hands

will the traitor be
honoured above the patriot.

But whoever proves his loyalty
to the state--

I'll prize that man in death as well as
life.

Of course, herein lies
the conflict of the play, as he ignores the "unwritten laws" that Antigone insists must
be upheld by giving her brother proper burial. We can therefore infer that Creon's
"principles" involve clinging on to power, whatever the cost, and harshly punishing any
form of rebellion, even if that brings him into contact with his own family or the Gods.
Creon, by clinging firmly to his principles throughout the play, therefore sows the
seeds of his own destruction and in the end loses everything. He remains an important
lesson for any would be despot about the dangers of authoritarian
power.