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A Soft Tooling Process Chain for Injection Molding of a 3D Component with Micro Pillars
Published on: August 4, 2018
Tablet coating by injection molding technology - Optimization of coating formulation attributes and coating process
Parind M Desai1, Vibha Puri2, David Brancazio3
1Novartis-MIT Center of Continuous Manufacturing, Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge 02139, MA, USA; Product & Process Engineering Department, GlaxoSmithKline, King of Prussia 19406, PA, USA.
Abstract:
We developed and evaluated a solvent-free injection molding (IM) coating technology that could be suitable for continuous manufacturing via incorporation with IM tableting. Coating formulations (coating polymers and plasticizers) were prepared using hot-melt extrusion and screened via stress-strain analysis employing a universal testing machine. Selected coating formulations were studied for their melt flow characteristics. Tablets were coated using a vertical injection molding unit. Process parameters like softening temperature, injection pressure, and cooling temperature played a very important role in IM coating processing. IM coating employing polyethylene oxide (PEO) based formulations required sufficient room humidity (>30% RH) to avoid immediate cracks, whereas other formulations were insensitive to the room humidity. Tested formulations based on Eudrajit E PO and Kollicoat IR had unsuitable mechanical properties. Three coating formulations based on hydroxypropyl pea starch, PEO 1,000,000 and Opadry had favorable mechanical (<700MPa Young's modulus, >35% elongation, >95×104J/m3 toughness) and melt flow (>0.4g/min) characteristics, that rendered acceptable IM coats. These three formulations increased the dissolution time by 10, 15 and 35min, respectively (75% drug release), compared to the uncoated tablets (15min). Coated tablets stored in several environmental conditions remained stable to cracking for the evaluated 8-week time period.
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