Stability of Sufentanil in a Syringe Pump under Simulated Epidural Infusion.

Sufentanil is a potent micro-opioid and centrally acting analgesic. In the management of acute postoperative pain, sufentanil is often administered epidurally using a standard syringe pump. For epidural administration, sufentanil is diluted to a concentration of 1 to 2 micrograms/mL with 0.9% sodium chloride injection. The stability of sufentanil in a syringe pump under simulated epidural infusion was studied using a stability-indicating high-performance liquid chromatography method. The concentration of sufentanil was determined in polypropylene syringes connected with a polyethlyene or polyvinyl chloride (PVC) tubing, filter and epidural catheter. Sufentanil concentrations remained constant in polypropylene syringes connected to epidural catheters and in the whole epidural infusion system using polyethylene tubing. Sufentanil concentrations decreased 7% to 15% in syringes connected to PVC tubing, polyethylene tubing and the whole epidural infusion system using PVC tubing. Adsorption of 17% of the sufentanil onto an epidural filter occurred during the first hour of the infusion; thereafter, sufentanil concentration remained stable at levels that were 5% to 15% below the theoretical concentration. In conclusion, adsorption of sufentanil should be considered when a new filter and tubing of different materials are used.