Searches: 'skin absorption, phencyclidine', 'mucous membrane, absorption, phencyclidine', 'delivery, phencyclidine', 'cutaneous absorption, phencyclidine', etc., as well as various key phrases from the few promising-looking hits I found. Tox profiles/reference articles/research papers all seem to deal with the methods of recreational PCP use, which are primarily smoking and injection. (I found a pair of papers on inhibiting skin absorption in mice, but they were such as to be unhelpful for this particular question.)
Any educated guesses (hopefully no empirical data)?