Here is a paragraph on this topic from the Purdue University Online Writing Lab (http://owl.english.purdue.edu/workshops/hypertext/apa/faq.html):
How do I cite my lecture notes?
The best approach to citing information from your own personal notes from a class lecture seems to be to consider it as a “personal communication” because it includes “unrecoverable data.” For this reason, personal communications are only cited within the text and are not included in the reference list.
For example, you might say:
In a lecture on November 16, 2002, to a PSY 235 class, Professor Smith said …
… (A. B. Smith, PSY 235 lecture, November 16, 2002).