SPME–GC determination of potential volatile organic leachables in aqueous-based pharmaceutical formulations packaged in overwrapped LDPE vials

A direct liquid immersion solid-phase microextraction–gas chromatographic (SPME–GC) method was developed and validated for the determination of 11 potential volatile organic compounds that may leach from preprinted foil laminate overwrap into aqueous pharmaceutical formulations filled in low-density polyethylene (LDPE) vials. The target compounds namely, ethanol, acetone, isopropyl alcohol, ethyl acetate, 2-butanone, n-heptane, isopropyl acetate, n-propyl acetate, toluene, diacetone alcohol and 1-propoxy-2-propanol, were suitably extracted from aqueous sample solutions by SPME using a 100-μm PDMS fiber, desorbed inside the GC inlet port, and analyzed using a J&W Scientific DB-1701 (86% polydimethylsiloxane/14% cyanopropylphenyl, 30 m × 0.53 mm i.d., 1.5-μm film thickness) capillary column with FID detection. The variables affecting the SPME absorption and desorption conditions were optimized and discussed. The average recoveries for all analytes varied from about 97.9 to 116.7% with the exception of n-heptane and toluene where the mean recoveries ranged from about 73.6 to 100.0% presumably due to their poor solubility in the aqueous sample matrix. The standard curves for all compounds were linear over the concentration range investigated with coefficient of correlations, r2 ≥ 0.98. The detection and quantitation limits ranged from approximately 0.6 ng/ml to 1.7 μg/ml and 5 ng/ml to 4.2 μg/ml, respectively, and the intra- and inter-day precision was considered adequate (R.S.D. ≤ 16%) for low-level determination of the target analytes in the sample matrix. The method was successfully applied for determination of the target compounds from preprinted foil laminate overwrap in selected aqueous-based pharmaceutical formulations.