(M1430-08-52) Systematic Root Cause Analysis for Investigation of Contamination Peak in an Ovicidal Topical Product

Purpose: The purpose of this study was to investigate a contamination peak observed during the method validation of an Ovicidal Topical Product and identify the root cause of the contamination.

Methods: During the Method Precision study, an unknown peak interfered with the main peak at the same retention. This interference was observed in the last three precision injections but not in the first three precision samples. A root cause or fishbone analysis was performed to determine whether any machine, method, material, man, or measurement was causing the issue. The interference was not noticed during the establishment of standard solution parameters, such as linearity and standard solution stability. To investigate, three precision samples were re-injected followed by six diluents, to confirm the hypothesis that the unknown peak was a late-eluting peak that appeared in subsequent injections. The same study was also conducted on a placebo of the same age as the active batch sample, and the injections were compared. The unknown peak was obtained only in the first 3-injections of diluents following the samples and not the next 3 injections. This confirmed the hypothesis that it is a late-eluting peak eluting in 4^th injection eluting approximately at 220 minutes with the run time of 60 minutes per method (refer Figure 1). To resolve the issue, a modified gradient program was implemented to bring the unknown peak's retention time from 220 minutes to 72 minutes in the same injection. This was obtained by introducing a 45-minute wash program with water: acetonitrile (35:65) after acquisition of all the necessary peaks in the first 50 minutes of the gradient. To ensure the consistency of the modified gradient, multiple bottles of large-scale sample and placebo were injected into the HPLC to observe the late eluting pattern and the peak was consistent at 72 minutes (refer Figure 2). Since only additional wash was added, no further validation was warranted.

Results: To understand the root cause of the peak, a different placebo and active batch of similar age were injected, and no peak was found in them. Therefore, it was noticed that the unknown peak was only found in the engineering batch sample and placebo manufactured in the manufacturing suite, but not in the lab scale batches of the sample and placebo of the same age. The unknown peak was also not observed in excipient compatibility studies. Upon historical review of the data, a similar pattern of late-eluting peak was observed in the manufacturing equipment compatibility study, where the 4^th injection after injecting transfer hose sample showed interference. Therefore, to confirm the hypothesis that the late-eluting peak was coming from the contact with the transfer hose, a lab scale batch which did not show any contamination peak was exposed to the transfer hose for about 24 hours and a sample was collected from inside the transfer hose. The analysis of this sample confirmed the theory that the transfer hose was the source of the contamination peak (refer Figure 3). The systematic investigation identified the root cause of the contamination peak as the contact with transfer hose used during the manufacturing scale-up process and since the product has high alcohol, the transfer hose material was not compatible. The modified chromatographic parameters were used to perform successful validation and be able to monitor any other contaminations with an extended wash.

Conclusion: The contamination peak in the Topical Product was caused by the transfer hose used during the manufacturing process. The study emphasizes the importance of maintaining equipment and properly identifying and mitigating potential sources of contamination in pharmaceutical manufacturing processes. The study highlights the importance of careful systematic investigation and testing to identify the root cause of unexpected results in pharmaceutical manufacturing processes.

Figure 1: Overlay for three Intermediate precision samples followed six diluent injections.

Figure 2: Overlay of six samples, three placebos, and two diluents with the modified gradient.

Figure 3: Overlay of lab scale sample control and exposed with transfer hose.