Determining Syringeability by Measuring Aspiration Volume of Polymer Solutions at Different Temperatures

Nova Southeastern University, Davie, Florida, USA

Objective. The study was conducted to determine syringeability of methyl cellulose (MC), carboxymethyl cellulose (CMC), and poly(ethylene oxide) (PEO) in terms of aspiration volume when subjected to different temperatures for abuse. Background. Despite the fact that synthetic gelling agents such as PEO are frequently used in deterring drug abuse via injection, solution properties of such polymers are sensitive to high temperatures of extraction, and as such less temperature sensitive gelling agents are highly demanded. Methods. A CT3 Texture Analyzer with a syringe probe was used to draw PEO, MC and CMC solutions (0.5, 1, 2, 2.5, and 5% w/v) into the syringe. The syringe plunger was attached to the probe, and the needle was immersed into the solution. The probe was pulled up to 40 mm mark at the speed of 0.5 mm/sec. A similar study was conducted at an elevated temperature. The polymer solutions were poured into a jacketed glass beaker attached to a water bath maintained at 90oC. The aspiration volumes were measured after 5 min. Results. At room temperature, aspiration volumes suggested greater difficulty level of the CMC solutions for syringeability compared to MC and PEO solutions. However, at elevated temperatures, aspiration of MC solutions did not lead any volume. The PEO solutions had lowest resistance for aspiration in both conditions. Conclusion. Aqueous solutions of cellulose derivatives, CMC and MC show better resistance toward syringeability than PEO solutions at room temperature as well as at elevated temperatures.