When good labels go bad.
A well-known label manufacturer became concerned about their product. Was the paper label safe? Was the glue on each label toxic? Could it leach through the plastic bottle…and contaminate the tablets? Overseas process quality is a constant threat. Click here to see how this story ends.
The Problem
A well-known label manufacturer had a big problem. Their process had changed – managed by an overseas vendor. And now they feared the label or perhaps the label adhesive might contain chemicals in levels that were unacceptable for pharmaceutical applications. Could the solvents used in the label glue present a risk to patients who take the tablets from those containers?
The Assignment
Recommended as a consultative problem solver with deep experience in leachables and extractables, Quantum Analytics Group was asked to meet with the manufacturer and suggest a plan. Complete testing of all known and unknown solvents used in the manufacturing process was the most immediate hurdle.
The Challenge
Typically, standard methods can be employed when looking for residual solvents in a product (lab receives glue samples) but for reasons unknown…the manufacturer refused to release samples of the actual glue to be tested. By order of the manufacturer, only the finished product (plastic labels) could be tested.
The Issues
The glue was almost impossible to collect from the labels that were submitted to the lab. The adhesive in question was sandwiched between two plastic sheets. Generating adequate samples for testing became extremely difficult.
The Timing
The label manufacturer was desperate to respond to their customer…quickly. The timeline associated with the labelling process back in the States could not be changed. Quantum was given just three weeks to test and record the glue samples.
The Approach
“Our job was to test the label glue for solvent levels…and since the timing was tight, we approached the job pragmatically”. “First and foremost, control what’s there… don’t stray too far from the original goal”.
The Solution
Headspace GC testing was our first choice for our situation. We would get the glue into solution, test and record. A straightforward solution. “We had used Headspace GC dozens of times as a fast and efficient way to test for residual solvents in packaging and pharmaceuticals.”
The Work
But the physicality of the sheet became a real problem. The glued sheets couldn’t be partitioned into the headspace gas volume with any accuracy. The samples would curl…and stick to the vial. “We crafted tiny metal frames to hold the samples and utilized 30-cell trays to accommodate larger samples – which resulted in an over-dilution scenario. Time was now becoming an issue”.
More Work
“We had to come up with a new procedure. We sliced the sample sheets into small, uniform rectangles of known weight and known dimensions. Then manually released the samples into the headspace solution”. “We prepared approximately 30 vials to validate the method and then run another 2 or 3 for the actual test”.
The Insight
“We were confident the GC headspace method would work…. But it was creative thinking within our pragmatic approach that prevented the clients’ restrictive sample issues from becoming a barrier.”
The Result
Ultimately, Quantum’s test revealed class II and class III residual solvents within the membrane glue but NOT at levels of significant concern.
The manufacturer was given a copy of the method validation. And a report of the analytical results from the testing. Labelling process. The entire process took just 13 days.
The Value
Additionally, the label-maker now had a reliable resource on call to test each and every new batch from their overseas vendor.
Quantum Analytics Group has been their analytical laboratory of choice for 5 years.