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Atomizing air. The pressure of the air used to atomize the coating solution can also induce defects if not set cor- rectly. Typically, as atomization air pressure increases, surface roughness decreases and the film becomes thin- ner. If the air pressure is excessively high, however, the nozzle forms smaller droplets that can dry prematurely, which tends to cause surface roughness because they don't have enough time to coalesce and spread. Severe cases are called spray drying. Conversely, if atomization air pressure is too low, the spray droplets become larger and that could cause film roughness. Inlet air. The temperature of the air coming into the coating pan affects how the coating dries. If the tempera- ture is too high, coating efficiencies decrease as the droplets spray-dry and are exhausted from the pan. The flow rate of incoming air is also important. If it's too high, the droplets could dry too quickly and film roughness could result, along with poor adhesion. As a result, the film loses tensile strength. The coating defects that result from elevated or deficient air temperatures are over-drying, over-wetting, poor film appearance, and overall poor quality. Pan speed. How fast the coating pan rotates can affect the number of times tablets pass through the spray zone. The greater the number of passes, the more likely you are to achieve coating uniformity, color uniformity, and batch-to-batch consistency. When the pan rotates too fast, however, tablet-to-tablet attrition is more likely, meaning more tablets will crack and/or break. Conclusion Every tablet formulation is unique and not every coat- ing solution is suitable for every core. Thus, you must test each coating to optimize its composition and determine the settings that will ensure reliable delivery and uniform film deposition. But the first step is to establish the CQAs of the coated tablet, including the release profile of the API. Make sure your coating supplier understands those CQAs so its staff can identify optimized coating solutions that mesh with your equipment's operational parameters to ensure a high-quality final film. T&C References 1. Han, S., Kim, C., Kwon, D. Thermal/oxidative degradation and stabilization of polyethylene glycol. Polymer 1997, 38 (2), 317-323. 2. Waterman, K. C., Arikpo, W. B., Fergione, M. B., Graul, T. W., Johnson, B. A., MacDonald, B. C., Roy, M. C., and Timpano, R. J. N-methylation and N-formylation of a secondary amine drug (varenicline) in an osmotic tablet. J. Pharm. Sci. 2008, 97(4), 1499- 1507. 3. Rossiter, W. J., Godette, M., Brown, P. W., Galuk, K. G. An investigation of the degradation of aqueous ethylene glycol and propylene glycol solutions using ion chromatography," Solar Energy Materials 11 (1985) 455-467. http://fire.nist.gov /bfrlpubs/ build85/PDF/ b85010.pdf Beverly Schad, M.S., is technical support manager at Sensient Pharmaceutical, 2515 North Jefferson Avenue, St. Louis, MO 63106. Tel. 314 286 7120. Website: www.sensientpharma. com. 18 April 2014 Tablets & Capsules 9_MVYWOHYTHOHUKSPUN The material matters in material handling 4-.=0(3;9(@ Won't bend, dent or deflect under heavy loads Smooth surface is easily cleaned Easy integration with process equipment More economical than metal; more durable than plastic 4-..,3*(7;9(@ 6HHXVLQ1<& -XQH %RRWK l a i r e t a m e h Th i t t m g n i l d n h l i t H T Y H O W Y V M _ 9 d n u t c e fl e d r o t n e d , d n e b t ' n o W e n a e l c y l i s a e s i e c a fa r u s h t o o m S h t i i t t i E N U P S K U H O H s d a o l y v a e h r e d d e t i e s s e c o r p h t i w n o i t a r g e t n i y s a E m ; l a t e m n a h t l a c i m o n o c e e r o M a g n i r b s e t i s o p m o c d e c r o fo n i e R u e c ma r ha p e h t o t e c n ma r o fo r e p . G F M s i P R F n i e m na g n i d a e l 0 5 0 6 - 8 5 4 ) 0 0 8 ( ee r fr - l l o t l l a C . m o c . y. a r t g fg m . w w w t i s i v r o t n e m p i u q e c i t s a l p n a h t e l b a r u d e r o m f o l e v e l w e n e l o h w e h t d n A . y. r t s u d n i l a c i t u www.techceuticals.com Solid Dosage Training, Troubleshooting, and Problem Solving Since 1989 Operator & Supervisor Training Your facility or ours • Formulating • Granulating • Tabletting • Blending • Coating • Packaging Get RESULTS! c-Schadart_12-19_Masters 4/3/14 2:35 PM Page 18