Spray-congealing congealed particles

Scott, M.W. Robinson, M.J. Pauls, J.F. Lantz, R.J. Spray congealing particle size relationships using a centrifugal wheel atomizer. J. Pharm. Sci. 1964, 53, 670-675. Cusimano, A.G. Becker, C.H. Spray-congealed formulations of sulfaethyliadiazole (SETD) and waxes for prolonged-release medication. J. Pharm. Sci. 1968, 57, 1104-1112. 

Scott, M., Robinson, M., Pauls, J., and R. Lantz. Spray congealing Particle size relationships using a centrifugal wheel atomizer. J Pharm Sci, 53 (1964) 670—675. 

Yajima T, Nogata A, Demachi M, Umeki N, Itai S (1996) Particle design for taste-masking using a spray-congealing technique. Chemical and Pharmaceutical Bulletin 44 187-191. 

For hot melt coatings, the bed temperature must be maintained below the melt point of the coating to congeal it on particle, but not so low as to cause spray congealing (droplets congealing prior to contact with a particle. 

Spray Congealing Spray dried enzyme powder can be incorporated into a molten fat or wax. This mixture is atomized through a rotary nozzle into a cooled chamber essentially equivalent to a spray drier tower. The atomized droplets cool, solidify into particles, and harden as they fall, resulting in round particles. A simplified box diagram of spray congealing process is shown in Figure 6.11. 

API (acetaminophen in this case) is heated above the wax melting point, but below that of the drug component. This process results in a suspension of the drug particles in the molten wax. When a nozzle is used to spray the atomized suspension onto cooled air, the molten droplets of suspension congeal, thus allowing the liquid components to encapsulate the solid API and resulting in packets of API particles encased in solidified wax. 

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