Pellets, preparation spheronization

Lovgren K, Lundberg PJ. Determination of sphericity of pellets prepared by extrusion-spheronization and the impact of some process parameters. Drug Dev Ind Pharm 1989 15 2375-2392. 

Fig. 22 Pellets prepared by different methods. Cross-sectional view of a pellet prepared by powder layering (A), cross-sectional view of a pellet prepared by extrusion/spher-onization (B), and size and shape of pellets prepared by extrusion/spheronization (C).

Pellets prepared by extrusion/spheronization have uniform cross-sectional area (Fig. 22B) but differ slightly in shape and size, which is based on the spheronization process following extrusion (Fig. 22C). 

An immediate release product would require some special feature to warrant the increased cost of production when compared to a conventional capsule or tablet. Therefore, the major commercial use of pellets prepared by extrusion/spheronization is in the preparation of controlled release products and there are several highly successful products available. In particular the ability to produce pellets with a high drug loading offers advantages over alternative methods of forming pellets. 

Perez JP, Rabiskova M. Influence of the drying technique on theophylline pellets prepared by extrusion-spheronization. Int J Riarm 2002 242 349-51. 

Sriamomsak P, Nunthanid J, Luangtana-anan M, et al. Alginate-based pellets prepared by extrusion/spheronization A preliminary study on the effect of additive in granulating liquid. Eur J Pharm Biopharm 2007 67 227-35. 

Souto C, Rodriguez A, Parajes S, et al. A comparative study of the utility of two super-disintegrants in microcrystalline cellulose pellets prepared by extrusion/spheronization. Eur J Pharm Biopharm 2005 61 94-9. 

Young et al. in 2002 successfully prepared controlled release spherical pellets of theophylline by HME and spheronization process. A Randcastle extruder was used to extrude the mixture of anhydrous theophylline, Eudragit 4135F, microcrystalline cellulose, and PEG 8000. Hot-melt extruded rods were cut into symmetrical pellets and then these pellets were spheronized at an elevated temperature. The dissolution profile of the spherical pellets was dependent on the matrix polymer solubility in the media. 

Varshosaz J, Kennedy RA, Gipps EM. Effect of binder level and granulating liquid on phenylbutazone pellets prepared by extrusion-spheronization. Drug Dev Ind Pharm 1997 23(6) 611-618. 

A reported application of canonical analysis involved a novel combination of the canonical form of the regression equation with a computer-aided grid search technique to optimize controlled drug release from a pellet system prepared by extrusion and spheronization [28,29]. Formulation factors were used as independent variables, and in vitro dissolution was the main response, or dependent variable. Both a minimum and a maximum drug release rate was predicted and verified by preparation and testing of the predicted formulations. Excellent agreement between the predicted values and the actual values was evident for the four-component pellet system in this study. 

Spherical pellets containing 5% triamcinolone acetonide were prepared by Villar-Lopez and co-workers [59] by extrusion/spheronization following formulation with microcrystalline cellulose and/or a hydrophilic excipient like lactose, sodium earbox-ymethylcellulose, or P-cyclodextrin. Their suitability for coating, with a view toward colonic drug deliveiy, was assessed in terms of their size, sphericity, and dissolution test response. The best results were afforded by a 5 90 5 composition of microcrystalline cellulose, P-cyclodextrin, and triamcinolone acetonide, prepared by complex-ation of triamcinolone acetonide with P-cyclodextrin prior to the addition of microcrystalline cellulose. 

Pellets. Pellets are mainly prepared by four different methods powder layering, rotating fluidized bed, extrusion/spheronization, and the agglomeration method. The oldest one is the so-called. 

Tomer G, Podczeck F, Newton JM. The influence of model drugs on the preparation of pellets by extrusion/spheronization 11 sphcronization parameters. Int J Pharm 2002 231 107-19. 

Chatchawalsaisin J. Podczcck F, Newton JM. The preparation by extrusion/spheronization and the properties of pellets containing drugs, microcrystallinc cellulose and glyceryl monostearate. Eur J Pharm Sci 2005 24 35-48. 

Newton JM. Pinto MR. Podczeck F. The preparation of pellets containing a surfactant or a mixture of mono and diglycerides by extrusion/spheronization. Eur J Pharm Sci 2007 66 83-94. 

These can be prepared by techniques like wet granulation, extrusion—spheronization, and hot melt extmsion, as illustrated in Figure 4.8. Solid self-nanoemulsifying pellets are documented to possess several advantages, such as flexibility of manufacturing, reduced intra- and/or intersubject variation in plasma profiles, and minimal G1 irritation (Serratoni et al., 2007). 

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