The only difference between MPQ2459GJ-AEC1P and MPQ2459GJ-AEC1Z is that “P” suffix calls out a 500-piece manufacturer tape and reel, and “Z” suffix calls out a 3000-piece manufacturer tape and reel.
Here is a link comparing the two - Integrated Circuits (ICs) | Voltage Regulators - DC DC Switching Regulators | DigiKey
Here is a link to the datasheet - MPQ2459 Datasheet | DigiKey