Effect of Shear Stress History on Polymer Solution Aspiration

Nova Southeastern University, Davie, Florida, USA

Objective. The study was conducted to determine behavior of methyl cellulose (MC), and carboxymethyl cellulose (CMC) in comparison with poly(ethylene oxide) (PEO) when subjected to shear stress for prolonged duration. Background. Use of gel forming agents in abuse deterrent formulations can potentially prevent drug abuse via IV route. However, these agents are susceptible to high shear conditions of multiple aspirations, which for the first time will be studied in this research. Methods. About 3 mL of 1% w/v solutions of PEO, CMC, and MC were taken into glass vials. A Brookfield CT3 texture analyzer with syringe probe was used to measure the drawing force. The syringe plunger was attached to the probe while the attached needle was immersed into the solution. The solution was drawn up into the syringe to the 3 mL mark by pulling the syringe plunger up using the probe. The probe was then pushed down to release the solution into a glass vial and was pulled up again. This procedure was repeated 15 times, and the pulling force was recorded. Results. This test shows that the syringeability of the PEO solutions is susceptible to their stress history. With increasing number of aspiration cycles, PEO solutions showed gradual decrease in drawing force, whereas the drawing force was increased for the MC solutions. Drawing force for the CMC solutions remained relatively unchanged. Conclusion. MC and CMC provide a feasible solutions to susceptibility of abuse deterrent formulations to shear stress.