Spheroniser

Hellen L, Yliruusi J, Merkku P, Kristoffersson E. Process variables of instant granulator and spheroniser I. Physical properties of granules, extrudate and pellets. Int J Pharm 1993 96 197-204. 

Hellen L, Yliruusi J. Process variables of instant granulator and spheroniser III. Shape and shape distributions of pellets. Int J Pharm 1993 96 217-223. Chapman SR, Rowe RC, Newton JM. Characterization of the sphericity of particles by the one plane critical stability. J Pharm Pharmacol 1988 40 503-505. Rowe RC, Sadeghnejad GR. The rheology of mcc powder/water mixes-measurement using a mixer torque rheometer. Int J Pharm 1987 38 227-229. O Connor RE, Schwartz JB. Spheronization II Drug release from drug-diluent mixtures. Drug Dev Ind Pharm 1985 11 (9-10) 1837-1857. 

Fine powders formed into plastic mass with aid of liquids and binders, extruded into pellets which are rolled into spheres. Pill making, spheronisation Automatic pill machines, Marumerizer ... 

Advantages Simplicity, cost efficiency Wide application range Spheronisation... 

Figure 16.11. Schematic of a spheroniser. The bottom plate rotates and the strands from the extruder are broken of and become spherically shaped due to the motion of the particles.

Battaille, B. Rahman, L. Jacob, M. Etude Des Parametres de Eormulation Sur Les Characteristiques Physico-Techniques de Granules de Theophylline Obtenus Par Extrusion-Spheronisation. Pharma. Acta Helv. 1991, 66 (8), 223-236. 

Edimo A, Leterme P, Denis J, et al. Capacity of lipophilic auxiliary substances to give spheres by extrusion-spheronisation. Drug Dev Ind Pharm 1993 19 827-842. 

Neau SH, Chow MY, Durrani MJ. Fabrication and characterization of extruded and spheronised beads containing Carbapol 974, NF resin. Int J Pharm 1996 131 47-55. Goskonda SR. Hillman GA, Upadrashta SM. Development of matrix controlled release beads by extrusion-spheronization technology using statistical design. Drug Dev Ind Phaim 1994 20 279-92. 

Povidone can be used in all the current wet granulation techniques, including fluidized bed granulation [82,156, 425] and extrusion-spheronisation [157,... 

A second approach is to spheronise the micronised particles, which gives a free-flowing powder which should break down easily on aerosolisation. The advantage is that there is no risk of poor homogeneity or segregation, but this is balanced by the difficulty of metering minute quantities of powders (spheres are typically 100-250 p,g). 

For the formulation, there is a significant problem of increasing the mass of powder during blending and especially for spheronisation, since a large mass can break down fragile spheres. Powder processing is usually carried out at controlled relative humidity (RH), usually <50 percent RH. 

One specialised method of particle agglomeration is extrusion and spheronisation, to produce spherical or near-spherical particles. Such particles are suitable for coating with release modifying coats to produce controlled release formulations. The particles are usually filled into hard gelatin capsules for administration to patients. The process of extrusion/spheronisation is depicted in Figure 11.22. 

There are many types of extruders available, with very different shear forces. The different shear forces will have an effect on the water distribution in the extrudates. As the water level is critical for optimising the spheronisation process, it is clear that the formulation development and process development need to be considered as one for this type of process. 

Sieving and di ting. 1 Pass tlu ough extmder RoUedinto spheroniser T ... 

Vervaet C, Remon JP. Bioavailability of hydrochlorothiazide from pellets, made by extrusion/spheronisation, containing polyethylene glycol 400 as a dissolution enhancer. Pharm Res 1997 14(11) 1644-1646. 

Tho I, Sande SA, Kleinebudde P. Gross-linking of amidated low-methoxylated pectin with calcium during extrusion/spheronisation effect on particle size and shape. Chem Eng Sci. 60 (14) 3899-3907, 2005. 

Bornhoft M, Thommes M, Kleinebudde P. Prehminary assessment of carrageenan as excipient for extrusion/spheronisation. Eur J Pharm Biopharm. 59 (1) 127-131, 2005. 

Thommes M, Kleinebudde P. Use of kappa-carrageenan as alternative pelletisation aid to microcrystalline cellulose in extrusion/spheronisation. 1. Influence of type and fraction of filler. Eur J Pharm Biopharm. 63 (1) 59-67,2006. 

Santos H, Veiga F, Pina M, Podczeck F, Sousa J. Physical properties of chitosan pellets produced by extrusion-spheronisation Influence of formulation variables. Int J Pharm. 246 (1-2) 153-169, 2002. 

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