How to clean enteric polymers

Why Common Approaches Are Not Effective

The mechanism of action for cleaning enteric polymers is straightforward. Because enteric polymers are chemically acidic, their solubility and therefore their release is pH dependent. As a result, one would assume that they can be easily cleaned with alkaline chemistry or detergents.

The wrinkle to this simplistic view is that the polymers are rarely used on their own. They are formulated with other excipients to improve their processing efficiency, to improve film or matrix properties, or to extend their shelf life. Furthermore, coloring pigments such as titanium or iron oxide are frequently added into the enteric coating formulation.The result is often a tough and sticky residue bonded to the stainless steel.

Similar to how a hammer will put a screw into the wall, traditional approaches to cleaning enteric polymers will get the job done, but it won’t be pretty and there will be repercussions down the road.

Common Approach 1: A two detergent process of alternating highly alkaline detergents for the polymer and highly a highly acidic detergent for the insolubles. Challenges with this approach include:

Time consuming procedure
Re-cleaning is often required when residues contain high pigment quantities.
Decreased productivity as a result of increased equipment downtime
Manual scrubbing may be necessary to remove pigment haze
Due to the use of highly alkaline and acidic detergents, safety is of concern, especially when manual cleaning is required
Excessive water consumption due to multiple detergent and multi-step process

Common Approach 2: Use of commodity products like sodium bicarbonate, sodium hydroxide and solvents. Challenges with this approach include:

Chemical strips away the polymer but doesn’t address the talc or pigment residue
Time consuming: Removal of this haze once it is separated from the formulation residue is extremely tough and needs extensive action such as scrubbing
Manual scrubbing may be necessary to remove pigment haze
Due to hazards of sodium hydroxide and solvents safety is of concern, especially when manual cleaning is required

Efficient Cleaning of Enteric Polymers

Although I’m not a handy [wo]man by any stretch of the imagination, I want to revisit the hammer and the screw analogy. There are thousands of different shapes and sizes of screws, and depending on if you are screwing into drywall, plaster, or concrete, you will need to make sure you match the right tool with the unique project at hand. The case at hand is a great example of requiring a detergent and process that target not only the enteric polymer, but the other ingredients too. If you want your equipment to look like this without manual scrubbing, then read on!