TY - JOUR T1 - Optimised process and formulation conditions for extended release dry polymer powder-coated pellets. AU - Terebesi,Ildikó, AU - Bodmeier,Roland, Y1 - 2010/01/15/ PY - 2009/09/13/received PY - 2009/12/20/revised PY - 2010/01/12/accepted PY - 2010/1/19/entrez PY - 2010/1/19/pubmed PY - 2010/12/14/medline SP - 63 EP - 70 JF - European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V JO - Eur J Pharm Biopharm VL - 75 IS - 1 N2 - The objective of this study was to improve the film formation and permeability characteristics of extended release ethylcellulose coatings prepared by dry polymer powder coating for the release of drugs of varying solubility. Ethylcellulose (7 and 10 cp viscosity grades) and Eudragit(R) RS were used for dry powder coating of pellets in a fluidised bed ball coater. Pre-plasticised ethylcellulose powder was prepared by spray-drying aqueous ethylcellulose dispersions (Surelease(R) and Aquacoat(R)) or by hot melt extrusion/cryogenic grinding of plasticised ethylcellulose. Chlorpheniramine maleate and theophylline were used as model drugs of different solubilities. The film formation process, polymeric films and coated pellets were characterised by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM) and dissolution testing. Film formation and extended drug release was achieved with ethylcellulose, a polymer with a high glass transition temperature (T(g)) without the use of water, which is usually required in dry powder coating. DMA-measurements revealed that plasticised ethylcellulose had a modulus of elasticity (E') similar to the low T(g) Eudragit(R) RS. With increasing plasticiser concentration, the T(g) of ethylcellulose was reduced and the mechanical properties improved, thus facilitating coalescence of the polymer particles. SEM-pictures revealed the formation of a dense, homogeneous film. The lower viscosity grade ethylcellulose (7 cp) resulted in better film formation than the higher viscosity grade (10 cp) and required less stringent curing conditions. Successful extended release ethylcellulose coatings were also obtained by coating with pre-plasticised spray-dried ethylcellulose powders as an alternative to the separate application of pure ethylcellulose powder and plasticiser. The permeability of the extended release coating could be controlled by using powder blends of ethylcellulose with the hydrophilic polymer HPMC. In conclusion, dry polymer powder coating is an interesting technique to achieve extended release of drugs with varying solubility as an alternative to classical coatings obtained from organic polymer solution or aqueous polymer dispersions. SN - 1873-3441 UR - https://www.unboundmedicine.com/medline/citation/20079833/Optimised_process_and_formulation_conditions_for_extended_release_dry_polymer_powder_coated_pellets_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0939-6411(10)00008-1 DB - PRIME DP - Unbound Medicine ER -