Spray congealing
Spray congealing
Spray congealing, also known as spray cooling, is a solvent free process that transforms a melt into well-defined spherical particles.
In recent years the technology has been used for controlled release formulation and also for taste masking. In the latter application it is particularly suitable for oral disintegrating tablets since it provides perfect encapsulation at particle level.
How it works
The API is dissolved (or suspended) in a melted excipient (typically a low melting point polymer) and atomized into cold nitrogen leading to solidification of the droplets and particle formation. The particles are then separated from the gas stream in a cyclone and/or a filter bag. This is a solvent-free process that makes use of spray drying assets as a means of isolating the newly formed particles.
Applications
Solid dispersions
Amorphous materials (drug + polymer) used to overcome solubility limitations of BCS class 2 and 4 drugs.
Microencapsulated particles
Crystalline drug encapsulated with a coating polymer. For example, enteric polymers can be used to protect drug from the gastric conditions or for enhanced delivery to the site of maximum absorption. Similar approaches can be used for taste masking and for protecting the drug from physical environments (e.g., light, moisture).
Pharmaceutical cocrystals
Cocrystals are multicomponent crystals of, at least, two molecules (API+coformer) combined in a stoichiometric ratio. Cocrystals have shown efficacy on improving aqueous solubility of poorly water-soluble APIs, hygroscopicity, stability, taste, and downstream processing capacity.
