Issue link: https://www.e-digitaleditions.com/i/1233462
14 April 2020 Tablets & Capsules the minitablets, a 10 percent weight gain was required as a process target. Table 1 shows the coating formulation parameters for both the pilot and production batches. Coating application Pilot coating tests were performed to investigate the coating formulation and determine the right parameters for a 20-kilogram batch. The pilot tests were conducted using an IMA Perfima Edge Lab coater with a 30-liter drum. This side-vented pan coater is specifically designed for coating small substrates such as pellets. The coater maintains the same drum shape, geometry, and spray system as a stan- dard tablet coater, but the drums are constructed using a slotted, wedge-wire screen (Photo 1) that allows air to pass through the drum during coating. Specially designed mix- ing baffles welded to the drum's center and sidewalls, as shown in Photo 2, allow the coater to handle a variety of substrates with different shapes and sizes. The pilot tests were done in triplicate to confirm process repeatability before scaling up. The process parameters were harmonized to maintain a stable tablet temperature of 42° to 45°C, and the process time for a 10 percent weight increase was less than 3 hours for each trial. Because the process parameters were optimized, the final yield for each trial was in the region of 99 percent. Once the parameters were fixed, the coating process was scaled up and performed using a production-scale IMA Perfima Edge coater with a 200-liter wedge-wire screen drum. Table 2 shows the coating parameters for both the pilot-scale and production-scale coaters. Scaling up from lab to production scale was easy because of the similar geometry between the pilot and production drums. Conclusions The coated minitablets produced in this study showed no visual defects or surface roughness. The combination of Surelease and Opadry resulted in an easy-to-apply coating that can be quickly and easily modified by adjusting the percentage of pore former and the coating weight gain to drug in the mouth. Also, as a non-ionic polymer, ethyl cellulose provides very low potential for drug interactions. Opadry is HPMC based and acts as a pore former in the coating, allowing immediate release of the drug once the tablets reach the stomach. An 80:20 Surelease-to-Opadry ratio was suggested by the supplier. The coating formulation was prepared by dispersing the Opadry in deionized water and then add- ing it to the Surelease to achieve a total solids content of 12 percent w/w. Due to the high total surface area of Table 2 Coating process parameters for both pilot- and production-scale coaters Parameter Pilot Production Batch size (kilograms) 23 82.50 Pan speed (rpm) 10-12 8-9 Peripheral speed (m/s) 0.45-0.54 0.50-0.57 Inlet air volume (m 3 /h) 700 2,600 Inlet air temperature (°C) 56-68 60-70 Tablet core temperature (°C) 42-45 42-45 Negative pressure (pascal) -30 -30 Spray rate (g/min) 120 400 Atomization air pressure (bar) 1.5 1.8 Pattern air pressure (bar) 1.4 1.6 Spray gun distance (centimeters) 20 22 Number or spray guns (Schlick ABC) 1 4 Nozzle diameter (millimeters) 1.2 1.2 Process time (minutes) 160 170 Photo 1: The coating drum is constructed using a slotted, wedge-wire screen that allows air to pass through the drum during coating. Photo 2: Specially designed mixing baffles welded to the drum's center and sidewalls allow the coater to handle a variety of substrates with different shapes and sizes.