Powder Characteristics of Proteins Spray-Dried from Different Spray-Dryers

Abstract

The powder characteristics of bovine somatotropin and casein spray-dried from laboratory, pilot and production spray-dryers were investigated. The powder characteristics examined included particle size distribution and morphology; bulk density; and flowability as measured by angle of repose, compressibility index and shear cell indices. Morphology classification showed internal voidage, blowholes, expanded, smooth and folding for somatotropin and casein spray-dried from the various spray-dryers. Particle size distributions of the bovine somatotropin and casein were unimodal and skewed. As the drying-chamber size of the spray-dryer increased, the particle sizes of both somatotropin and casein increased from mean volume diameters of 6-8 p using the laboratory and pilot spray-dryers to 13-24 p when using the production size spray-dryers. Spray-dried bovine somatotropin and casein had bulk densities of 0.090 to 0.195 g/cm3. Three flowability tests showed casein and somatotropin spray-dried from the different spray-dryers exhibited poor flow which could result in pharmaceutical manufacture challenges. The morphology and flowability of the two spray-dried proteins remained the same when comparing material produced from all four spray-dryers. However, the mean volume diameter, particle size distribution and bulk density did vary which might change critical product characteristics during scale-up. In general, similar morphology, particle size distributions, flowability and bulk densities were observed when comparing spray-dried casein and bovine somatotropin produced from the same model spray-dryer. Casein is recommended as a model protein for powder characterization during spray-drying and early formulation manufacture process development when adequate quantities of the recombinant protein are not available. 1705

Scaling Up the Spray Drying Process from Pilot to Production Scale Using an Atomized Droplet Size Criterion

“…The experimental setup suggested in Table II gives a total of 2 5 =32 experiments, 16 performed in open-cycle and 16 in closed-cycle. All the experiments performed in closedcycle were carried in duplicate in order to evaluate the repeatability of the spray drying process.…”

“…Most of the research published describes scale-up within the same equipment (14) or covers scale-up from laboratory to pilot plant (15). Only a few papers deal with spray drying in production scale (16,17), and none of these studies aimed at matching certain product characteristics such as particle size distribution. According to Zlokarnik (18), it is not surprising that scale-up of spray dryers has not been studied in detail.…”

Combined effects of spray-drying conditions and postdrying storage time and temperature on Salmonella choleraesuis and Salmonella typhimurium survival when inoculated in liquid porcine plasma

“…Laboratory spray‐dryers are useful for establishing guidelines to scale‐up the industrial production of SDP. The main differences between laboratory and pilot plant dryers compared with industrial dryers are design, size and volume processed, all of which affect the retention or dwell time of the product within the chamber (Foster and Leatherman ). Laboratory spray‐dryers have reduced retention or dwell time of the product within the chamber (<1 s) compared with commercial dryers (between 20 and 90 s, depending upon scale and design of the dryer).…”

Commercially produced spray-dried porcine plasma contains increased concentrations of porcine circovirus type 2 DNA but does not transmit porcine circovirus type 2 when fed to naïve pigs

“…The outlet temperature and rapid changes in temperature and pressure exert significant effects on microbial survival (To and Etzel, 1997a,b;Lian et al, 2002;Ananta et al, 2005). The design of the drying chamber affects the air flow and retention time of the particle within the drying chamber (Foster and Leatherman, 1995). The total time exposed to increased temperatures has been shown to affect microbial survival (APC Inc., Ankeny, IA, unpublished data) and is affected by the design of the system separating the dried particle from the heated air and transporting the dry powder to final packaging.…”