Cleaning and Care of Dissolution Components, or How to Save $$$ in the Lab
Many of the common problems that I see in dissolution laboratories come down to cleaning issues in the lab. Frequent breakdowns of autosampling equipment, bent and rusty baskets, flaking PTFE paddle shafts, and some run failures can all be avoided or minimized by implementing proper cleaning in the dissolution laboratory.
When it comes to cleaning dissolution components, there are a few main points to keep in mind:
1) Clean as soon as possible after a run is complete. Cleaning as soon as possible helps with a couple major issues. First, it prevents drying or precipitation of your drug, excipients, and media components in tubing, valves, etc. Secondly, it reduces the attack of acids on stainless steel and other components.
2) When you do clean, don't use any abrasives or anything that could damage the components. Avoid the use of rough sponges or abrasive cleaning agents. If cleaning water baths, avoid alcohols and bleaches - or anything not safe with acrylics.
3) The cleaning being performed should be based on the samples you've run. Different samples and media will often require different cleaning approaches. Media with surfactants and salts is often cleaned best with DI Water. Samples that contain polymers may require use of alchols to help clean the system. Runs with both surfactants/salts, and polymers may require several rinses of Water/Alcohol/Water.
Some cleaning recommendations that I offer based on the item are as follows.
Paddles and Basket Shafts - Clean with soap and water. A paper towel with soapy water can be used to clean the shafts, and then followed with a squirt bottle of DI Water. If the product or media is viscous in any way, you may need to use alcohol or other products as well. If polymer is left on the shafts, it will also have acid/salt/etc. of the media with it which will concentrate and lead to rapid rusting. I prefer to clean shafts on the dissolution unit. If you're removing them, make sure to store them properly so they don't hit each other. Original containers, wrapping in bubble wrap or felt, or other options are all good.
Baskets - Only handle baskets by the top ring when putting them on or taking them off of shafts. When cleaning, rinse them gently in the sink. Next, put them in a beaker with ethanol or methanol and sonicate them for about 5 minutes. Remove them and allow them to air dry. Place them into a protective container when done. Baskets should appear shiny, if they appear dull/flat in color (like the basket pictured on the right of the header picture) it is time to replace them.
Vessels - Clean with soap and water, and a non-abrasive washcloth or other item. When removing from the dissolution bath, remove back vessels first to reduce the chance of accidentally spilling your media into your water bath. Dishwashers are acceptable for glass-lipped vessels, but may not be for plastic-lipped ones - check with your manufacturer. Don't use brushes if possible.
Cannulas - Treat these the same as shafts. Cannulas are often overlooked when cleaning.
Autosamplers - Cleaning solutions must be based on what you're testing. DI Water works best for salts, sugars, and surfactants. With many autosamplers, you can heat DI Water to 50-60C to improve solubilization of residues in lines. Alcohols work well for polymers and difficult to clean products. I always recommend the final rinse be with DI Water. Some autosamplers, such as the Agilent 850-DS, can have an integrated autoclean which will occur immediately after the final timepoint to prevent drying.
If you want more cleaning information, or just want to hear me talk, check out the cleaning webinar at: https://tinyurl.com/hs4zym9