First, you need to decide if you need to apologize for missing the meeting. Why were you invited? You may have been invited informationally, so that you were aware that a meeting to discuss a particular issue was happening and so you would know a resolution may be coming soon. Alternatively, you may have been invited because you either need the information provided to effectively work or have information that someone else needs to work. If you were invited informationally, then it may not be necessary to apologize at all - your attendance was optional. However, if you were invited as a contributor, you should touch base with the meeting organizer.
If it is the case that you were invited as a participant, you should apologize and either obtain the information that you need or provide the information that you need. You shouldn't make a big deal out of it, though. A very quick apology, followed by getting or giving the information that you need to. In the future, make every attempt to either make the meeting on-time or inform the organizer of your inability to be present and provide your contributions as soon as possible (before or after the meeting).
Again - don't make a big deal about it (a brief "I'm sorry for missing the meeting, here's my contribution" and move on), don't do it in public (talk to the meeting organizer in private), and learn from your mistakes.