Extraction of o-phenylphenol from silicone tubing by a sulfobutylether cyclodextrin formulation

During a compatibility study between a formulation containing sulfobutylether cyclodextrin (SBECD) and silicone tubing, an extraneous peak was observed in the HPLC chromatograms. The extraneous material was identified by LC/MS, MS/MS and UV as a previously unreported tubing extractable, o-phenylphenol (o-PP). Several studies were conducted to assess the impact of formulation and process-related variables on the amount of the o-PP extracted, including contact time, sulfobutylether cyclodextrin concentration, formulation pH, and tubing sterilization and storage conditions. Results show that the concentration of the SBECD, tubing processing and storage conditions and the duration of the study influenced the levels of o-PP extracted. However, the largest contributor to the amount extracted was the lot of tubing tested. The extracted levels varied widely from lot to lot (0.007-3.89microg/cm(2) of tubing surface area). A dynamic study conducted to simulate a manufacturing process also resulted in the extraction of o-PP by the formulation.