In this work, the stability of new agglomerated nasal powders prepared with morphine microcrystals mixed with spray–dried microspheres of mannitol-lecithin are presented. Vibration on a sieve pile induced the agglomeration of microsphere and crystal mixtures. In conclusion, spray drying of morphine solution modified the crystal form of drug to amorphous microparticles. Agglomeration and stability of these microparticles depended on the excipient used. It was innovative to find that agglomerates for nasal delivery could be obtained from mixtures of morphine crystals and spray–dried microspheres of mannitol-lecithin, with advantages for the stability of the drug.