Found 3 alternatives for APT1231 by Panasonic Electric Works. Optoisolators Triac Scr Output — 4-DIP (0.300", 7.62mm).
OPTOISOLATOR 2.5KV TRIAC 4DIP
OPTOCOUPLER PHOTOTRIAC 800V DIP4
OPTOISOLATOR 5KV TRIAC 4DIP