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Manufacture Dosage Forms, Technology and Equipment, Formulation, Facilities

The Power of Productivity

sponsored by Colorcon

Why is coating important? Aesthetically, a coated tablet looks more appealing, which can impact how a patient feels about their medicine. A well-presented coated tablet, free from defects, gives patients confidence that it’s high quality and a trusted product from a reputable company. A coated tablet also provides many important advantages directly to the consumer. Consider patient compliance as one example. An uncoated tablet will often be chalky and, for some patients, unpalatable, since there is nothing to mask the texture or taste. There is also a high chance that the tablet will stick during the swallowing process. If a patient finds taking their medicine difficult or unpleasant then they are less likely to adhere to the prescribed regimen. Coatings can help overcome this issue. For example, we have developed Opadry EZ, easy swallow coating, which provides exceptional slip when the coating becomes wet, making the tablet easier to swallow. This can be particularly important where a large tablet size is unavoidable. 

A coating also provides the opportunity for differentiation and prevention of medication mix ups. Some companies choose a simple white coating, but when all tablets look the same there is a higher risk of errors, particularly where patients must take multiple medications. The FDA encourages companies to consider differentiation – especially amongst various dosage levels.  Application of a pigmented coating can help to avoid dispensing and administration of the wrong dosage or other look-alike errors. Going back to aesthetics, including color can also make a tablet look more attractive and impart stronger brand recognition. 

In addition, coating can convey specific functional properties to a tablet, such as moisture barrier protection or light protection; and modified release coatings allow the drug release to be delayed or targeted to a specific site. 

Reaching for higher productivity

Over the years, film coatings have evolved significantly. The standard coating system traditionally used HPMC (hypromellose) as the main polymer, which is still widely used. HMPC-based coatings provide adequate performance, but there is room for improvement. HPMC coatings may not adhere well to the tablet and are typically slow to apply, resulting in low production speeds. The subsequent introduction of PVA-based coatings gives greater flexibility with improved functionality, providing an opportunity  for faster production, which in turn means less potential for defects. Most recently, Opadry QX, a quick and flexible coating system, has been developed. Based on a PVA-PEG copolymer system, this coating formulation allows for the highest solids dispersion level, resulting in the greatest process efficiency – some of our customers have reported a 40 to 50 percent boost in productivity by switching to Opadry QX. Buying back machine time can make a huge difference in reducing bottlenecks in production and providing an opportunity to increase coating operations. 

We have also evolved from art to science in the area of sugar film coating. Sugar-coated products are very aesthetically pleasing because they have a smooth, glossy surface, with a sweet taste that can mask bitter-tasting ingredients. But the biggest challenge with a sugar coat is productivity and reproducibility. Sugar-coating is a very labor intensive and time-consuming manual process – and the finish, from batch-to-batch, can vary depending on the person performing the coating operation. 

Bringing in science to bridge the gap, Opadry SGR has been developed. This product is designed to deliver a high gloss, aqueous sugar film coating system that can be used in automated processes (fully perforated or conventional coating pans retrofitted with spray capability), allowing for significant time savings; down from days to a couple of hours. 

Ultimately, the coating you choose for your tablet will depend on your requirements. For some companies, high productivity is not possible or necessary, particularly if they are using older equipment, or labor cost is not a factor. But for others who are running at full capacity, a move to a higher solids and higher productivity coating may allow them to achieve a greater throughput with their existing assets and delay the need to invest in additional coating equipment.

Coating equipment and geographic location can also dictate choice of coating. It is not uncommon for companies to develop a drug in one region, where equipment and conditions are spot-on, before moving commercial production to another region, where coating equipment may not be as reliable, or where there are issues with airflow, temperature or humidity that present production problems. Choosing a coating that is flexible enough to be used across a range of different conditions while still giving consistent defect-free, flawless coating is a must.

Clean label appeal

A more recent trend that may affect coating decisions is the increasing consumer interest in cleaner labels. Most of this activity is coming from the nutraceuticals industry; in France, for instance, the use of titanium dioxide has recently been suspended for use in food and nutritional supplements, and companies are wary of similar moves in pharmaceuticals and want to get ahead of the curve. In response, we are now actively promoting titanium-free coatings and are getting interest from customers wanting to move to alternative coatings. 

Dangers of “DIY”

Some pharmaceutical manufacturers design and manufacture their own coating, but the majority will buy a ready formulated coating system because it is a simpler, more efficient process than a DIY (do it yourself) approach. Using an in-house coating necessitates the sourcing and associated quality testing of various raw materials from several vendors who may need to be audited and approved.  Additionally, inventory will be required for all of these materials, along with dispensing and dispersion preparation operations. Dispensing your own coating materials introduces cleaning considerations and risk for cross-contamination. Creating a stable, consistent coating is not always the easiest process either, especially if you’re not a coating expert. Color consistency and uniformity can be significant challenges, as color is contingent on the particle size distribution of pigments and, therefore, any batch-to-batch inconsistency will result in color variation. 

If you purchase a ready formulated coating system then you are buying one material from one vendor, which makes for a much simpler supply chain! Plus, the vendor will perform the quality audits of its own suppliers, have second sources of supply and provide regulatory support. It is, however, important to choose a trusted and reputable company. Looking at a company’s business continuity plans (BCP) is crucial to ensure reliable supply. Regional manufacturing is becoming an important trend in the pharma industry. At Colorcon, we have seven manufacturing plants located strategically across the globe, which means they can meet the needs of the local market. Importantly, all of our plants are operating with the same raw materials, same equipment and the same processes – and we have done a lot of work to validate the interchangeability of products from all the sites. If there is an issue getting material from one plant then we can simply supply it from another. We also have technical support laboratories worldwide to help customers through the coating process; enabling them to run trials in our coating labs (they may not have the equipment spare in their own company to run trials), seeking advice from us in terms of troubleshooting, or participating in our “Coating School” training sessions, which cover how best to manage and optimize the coating system. 

By partnering with a reputable and trusted company with plans in place to ensure supply then you reap the rewards of a consistent finish developed by coating experts that can also aid productivity! 

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About the Author
Kelly Boyer

Film Coating General Manager at Colorcon.

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