Spray granulation for drug formulation

Abstract

Fluidized bed granulation is a popular technique for pharmaceutical production, as it is a highly economical and efficient one-pot process. The research and development of process analytical technologies (PAT) has allowed greater process understanding and control to be achieved, even for the lesser known fluidized bed techniques, such as bottom spray and fluidized hot melt granulation. In view of its consistent mixing, as well as continuous and concurrent wetting and drying occurring throughout processing, fluidized bed granulation shows great potential for continuous production although more research is required to fully implement, validate and integrate the PAT tools in a production line.

Three-dimensional computational fluid dynamics (CFD) study of the gas–particle circulation pattern within a fluidized bed granulator: By full factorial design of fluidization velocity and particle size

“…Recently, binder spraying parameters such as spray rate, atomization pressure and pulsed spray frequency, have been extensively studied [9][10][11]. In particular, adjusting the pulsed frequency of binder spray was shown to be an effective way of controlling the granule size during spray fluidized bed granulation, in which the liquid feed is interrupted in regular sequences that allows drying and rewetting of granules [11][12][13].…”

Investigation on Side-Spray Fluidized Bed Granulation with Swirling Airflow

“…Chlorpheniramine maleate (BP grade, China) was used as a model drug. (18) Granules are irregular in shape (18) "One-pot" system for contained production (19) More spray drying of binder solution Bottom spray Smaller granules (20) Denser granules (20,21) Spherical granules with better flow (21) Slower granule growth (20) Smoother surface granules (22) Higher risk of overwetting Less spray drying of binder solution (23) Need reasonably well flowing feed powders Robust process at low spray rate (21). Tangential spray Supports higher spray rate (24,25) Denser granules (25,26) Less dependent on flow properties of powder feed (26) Material loss due to adhesion to friction plate (26) Powder elutriation only at higher airflow (24) Scale-up designs are expensive and impractical Granule growth is relatively uniform (25) Risk of bed overwetting is high Granules have good flow properties (25,26) Granules have low friability (25) Homogeneous drug distribution (26) …”

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“…Unsuitable for moisture sensitive and thermolabile materials. 68 : It was a continuous process where a dry granular product was obtained by feeding a solution or a suspension of active agent with or without excipients to the drying system where the feed was atomised and dried with a heated gas stream followed by subsequent separation of granular product from the gas stream. Alternately particle agglomeration was brought about by spraying the binder solution onto bed of powder particles in fluidized state achieved with the passage of air followed by drying using hot air.…”