Poster H8 - Investigating the Stability of Ethyl-Cellulose Ethanol Under Long Term Room Temperature Storage

Friday, October 25, 2024

10:00 AM – 11:00 AM EST

Location: Exhibit Hall E, F & G

Presenting Author(s)

Matthew Somerville

Undergraduate Student
University of Maryland
Owings Mills, Maryland, United States

Primary Investigator(s)

Jenna Mueller, PhD (she/her/hers)

Assistant Professor
University of Maryland
College Park, Maryland, United States

Co-Author(s)

MW

Melodi J. Whitley

Assistant Professor of Dermatology
Duke University School of Medicine, United States

Introduction: Ethyl-cellulose ethanol (EC-ethanol) has shown promise as a low-cost ablative therapy in various applications, including treating liver cancer, breast cancer, and cervical dysplasia (2-4). However, the stability of EC-ethanol when stored at room temperature remains largely unexplored, which is critical for developing a manufacturing plan for future clinical trials. Previous experiments have established that EC-ethanol maintains its properties when stored at room temperature for 24 hours; however, the true length of its long-term stability and efficacy remains unknown. This research seeks to fill this knowledge gap by conducting a comprehensive analysis of EC-ethanol's gel front formation properties and its ability to maintain ablative efficacy over 190 days of room-temperature storage.

Materials and

Methods: EC-Ethanol was prepared at varying concentrations (6, 9, and 12% EC-ethanol, w:v) and stored at room temperature in 1 mL Luer lock syringes (8 syringes per concentration) sealed with a Luer lock syringe cap. Each syringe was vortexed twice at 2000 rpm for 30 seconds. First, immediately prior to storage, and again immediately prior to testing. Two syringes at each concentration were tested within 24 hours of EC-ethanol preparation to establish a baseline control. One remaining syringe of each concentration was selected ~every 30 days for the remainder of the experiment. Each syringe was injected into a 1% agarose gel phantom to model a soft tissue injection (1). Specifically, a 27G 0.75-inch needle was inserted into the agarose phantom to a depth of 0.75 inches and 0.25 mL of EC-ethanol was injected into the phantom at a rate of 10 mL/hr with a syringe pump. Once the total volume had been injected, the gel front was given 5 minutes to develop prior to analysis. The phantom was then sectioned to expose the EC gel front, which was subsequently imaged with a digital camera. The gel front is directly related to the stability and potency of therapy as the amount of gel formation governs the drug distribution in tissue4. The EC gel front was then quantified using ImageJ, and the total area and average thickness (width) of each timepoint was compared to the baseline to determine if gel formation was altered by storage time at room temperature.

Results, Conclusions, and Discussions: A comparison of the average area and width of the EC gel front for each concentration of EC-ethanol over time is displayed in Figure 2. The findings were comparable to previous literature on EC-ethanol agarose gel phantom injections with the average gel front area and width increasing with higher concentrations (1). Notably, the differences between the average gel front area and width for each concentration were deemed not statistically significant across all time points of the 190-day experiment (Figure 2, statistical significance determined using a Kruskal-Wallis test, p>0.05).

In conclusion, room temperature EC-ethanol storage in syringes maintains its gel formation properties over 190 days, and a 24-month study is currently underway. This shelf life provides an excellent opportunity for clinical usage as preloaded EC-ethanol syringes can be shipped and stored at room temperature preventing the need for complex storage requirements or for EC-ethanol production to occur on-site. Additionally, the findings from this study provide valuable insights into the practicality of using EC-ethanol in clinical settings and inform strategies for its storage and handling, which will guide future clinical trial design.

Acknowledgements (Optional): 1. Adhikari, G., Sarojasamhita, V. P., Powell, V. R., Farooqui, A., Budzinski, M., Garvey, D. T., Yang, J., Katz, D., Crouch, B., Ramanujam, N., & Mueller, J. L. (2024). Impact of Injection-Based Delivery Parameters on Local Distribution Volume of Ethyl-Cellulose Ethanol Gel in Tissue and Tissue Mimicking Phantoms. IEEE transactions on bio-medical engineering, 71(5), 1488–1498. https://doi.org/10.1109/TBME.2023.3340613

2. Morhard, R., Mueller, J. L., Tang, Q., Nief, C., Chelales, E., Lam, C. T., Alvarez, D. A., Rubinstein, M., Katz, D. F., & Ramanujam, N. (2020). Understanding Factors Governing Distribution Volume of Ethyl Cellulose-Ethanol to Optimize Ablative Therapy in the Liver. IEEE transactions on bio-medical engineering, 67(8), 2337–2348. https://doi.org/10.1109/TBME.2019.2960049

3. Nief, C., Morhard, R., Chelales, E., Adrianzen Alvarez, D., Bourla Bs, I., Lam, C. T., Sag, A. A., Crouch, B. T., Mueller, J. L., Katz, D., Dewhirst, M. W., Everitt, J. I., & Ramanujam, N. (2021). Polymer-assisted intratumoral delivery of ethanol: Preclinical investigation of safety and efficacy in a murine breast cancer model. PloS one, 16(1), e0234535. https://doi.org/10.1371/journal.pone.0234535

4. Quang, T. T., Yang, J., Kaluzienski, M. L., Parrish, A., Farooqui, A., Katz, D., Crouch, B., Ramanujam, N., & Mueller, J. L. (2023). In Vivo Evaluation of Safety and Efficacy of Ethyl Cellulose-Ethanol Tissue Ablation in a Swine Cervix Model. Bioengineering (Basel, Switzerland), 10(11), 1246. https://doi.org/10.3390/bioengineering10111246