Q: Can you describe the start-up/shut-down sequences in more detail?
A: JVM- During start up and shut down the coater is in batch mode, the recipe calculates a spray nozzle sequencing that delivers an appropriate amount of weight gain to the tablets based on their position in the length of the drum
Q: How high of a solids load in solution can be handled by these coaters?
A: JVM- So far, with success we have tested this continuous process up to 35% solids, but it must be noted that these are special formulations designed by Ashland, Colorcon and others to run at these concentrations, whilst still maintaining a reasonably low viscosity
Q: What is highest weight gain that can be achieved with continuous coating?
A: JVM- we have run processes up to 8-10% weight gain in True-continuous mode, but with this higher residence time and slower throughput it can have an effect on uniformity, so this would be product and formulation dependent. In Batch-continuous mode weight gain can go higher similar to any batch coater
Q: Just curious, whether continuous process only for film coating or we can use for conventional sugar coating also?
A: JVM- we have not tried for sugar, but likely could be done, but not at high weight gains, due to uniformity issues
Q: What’s the temperature profile of the tablets/capsules as they move through the coater?
A: JVM- temperature should be constant along the length of drum based on even airflow and spray rate, small zone at beginning and end for preheat and drying of tablets
Q: What is the Engineering Design Features that make this Coater easy to design and easily execute a validated cleaning protocol?
A: JVM- the cleaning process is fully automatic except for some minor manual intervention, so it is easy to repeat validated cleaning process. There are several cleaning variables such as time, temperature, number of stages, etc. that can be adjusted within recipe to optimize cleaning recipe
Q: How about with a clogged nozzle midrun
A: JVM- only reason nozzle usually clogs is because it was not cleaned or set up properly and this usually happens in the first 10-15 minutes. Anytime during the coating run it is easy to pause process, pull out spray boom and clean and or exchange nozzle, and then push resume just like batch coater
Q: Even with anti-bearing spray nozzles sometimes you still get clogged nozzles or buildu
A: JVM- Perhaps eventually, but not usually, we have one client that runs 24 hours continuous before they intervene and clean nozzles
Q: What is the direction of inlet process air and exhaust air?
A: JVM- process air comes from above, through pan and they back up through the roof of the coater to exhaust system
Q: Switching to FCC, do we need to set process parameters in conventional methods?
A: JVM- most of the coating process parameters can be determined in a batch coating mode same as standard batch tablet coater. Only tablet feed rate, tilt and weir position need to be adjusted in continuous mode
Q: Could heating not have negative impacts on the tablets during the coating process?
A: JVM- In continuous mode, no more heat than traditional side vented batch coater, in start-up and shut-down mode there is option for air to be diverted when tablets are not being sprayed to avoid overheating. IE as with Ibuprofen
Q: What are big challenges for continuous coating of peptide as API since they need to be coated at Low temperature, typically 31-35 C? Would it be beneficial compared to batch coating? How do you control nozzle blockage in continuous coating?
A: JVM- have not had experience with this, but much larger volume of air can be passed through product bed in continuous coater, allowing drying at lower temperatures, and better temperature control. Desiccant drying also recommended for this.
JVM- only reason nozzle usually clogs is because it was not cleaned or set up properly and this usually happens in the first 10-15 minutes. Anytime during the coating run it is easy to pause process, pull out spray boom and clean and or exchange nozzle, and then push resume just like batch coater
Q: This question was in relation to “no manual intervention”
A: JVM- coater can be automatically loaded, coat batch to competition and fully emptied, feasibly without operator even being in coating room
Q: How are you using PAT concept?
A: JVM- right now with on-line weight checking devices, but there are also NIR technologies that allow for coating progress and quality analysis
Q: How high does the operating temperature get? Is thermolability of API ever a concern?
A: JVM- If it can be processed in batch coater, can be processed in continuous coater
Q: How many commercial pharma products are manufactured using continuous coating process?
A: JVM- 50-100+ perhaps, many generic and OTC formulas around the world in more than 20-25+ different companies
Q: Do you have example case studies applying QBD in continuous process development?
A: JVM- Have not closed loop on PAT monitoring, something we plan to do in future
Q: Spraying at 35 % of solids the Surface of the Tablet is still smooth?
A: JVM- definitely not as smooth as at 20% but still within allowable quality limits for most products
Q: Is it possible to get coated tablets with the same smooth Surface and gloss at 35 % of solids?
A: JVM- Similar to 20%, but perhaps not quite as, but again within quality limits from what we have seen