A Novel Method for the Determination of Propylene Glycol and Glycerine from Various Biological Matrices – Suitable Biomarkers for E-Cigarette Consumption

A novel method for the determination of propylene glycol and glycerine from various biological matrices – suitable biomarkers for e-cigarette consumption

Heinz-Werner Hagedorn, Nikola Pluym, Gerhard Scherer, Max Scherer Analytisch-Biologisches Forschungslabor (ABF) GmbH, Goethestraße 20, D-80336 Munich, Germany Abstract

E-cigarette use, also referred to as vaping, is worldwide increasing. E-cigarettes are becoming a preferred alternative for conventional cigarettes among smokers becoming a subject of a public health dispute. Despite the popularity e-cigarettes have gained worldwide, very little rigorous research has been performed in terms of product control and the effects of these devices on human health. The systematic and objective assessment of the actual dose by suitable analytical methods is a pre-requisite for the toxicological evaluation of this new product category. Particularly, the systematic evaluation of the quantitative assessment (dosimetry) of the main e-liquid components (nicotine, propylene glycol (PG) and glycerine (G)) as well as the uptake into the human body via the route of inhalation 2015_STPOST22_Hagedorn(Scherer).pdf is currently almost completely missing. We developed and validated a bioanalytical method for the quantification of PG and G in various human body fluids (plasma, urine, saliva) . The method combines the separation power of gas chromatography in conjunction with the high specificity provided by MS detection. Method validation according to FDA guidelines showed excellent results in terms of sensitivity, reproducibility and robustness . Moreover, the use of minimal sample volume along with a straightforward sample extraction procedure allows a time- and cost-efficient analysis of these compounds in large clinical studies. The method was applied to samples derived from an e-cigarette pilot study. This poster presentation will share the outcome of PG and G analysis in body fluids derived from an e-cigarette pilot study and will discuss their potential as biomarkers of exposure to e-cigarettes. Method principle Method characteristics Results of the e-cigarette pilot study Sample preparation GC-MS Parameter G PG 1. E-liquid characterization Analysis of the liquid LOQ (LOD) 0.05 µg/mL (0.02) 0.2 µg/mL (0.07) • 100 µl biofluid required • 1 µl injection volume (“USA- Mix”) (Plasma, Urine, Saliva) Linear range 0.5 – 20 µg/mL 0.5 – 10 µg/mL -Nic + Nic • Separation on a DB-Wax column Label 60:40 60:40 Stable-isotope labelled internal standards Accuracy 104 –113 % 97 –104 % Glycerine Propylene glycol PG:G • • EI, SIM mode Found 39:61 37:63 13 13 ( C3-G and C2-PG ) Precision CV 1.5 – 5.6 % CV 1.6 – 4.3 % Nicotine Label 0 18 (mg/ml) • Derivatization with acetic acid anhydride Found 0 2.6 ‹ A suitable method has been developed and validated for the analysis of 2. Nicotine uptake PG and G from various body fluids.

IS PG E-Cigarette pilot study PG Quantifier

Objectives:

IS G ‹ Quantify the uptake of nicotine from e-cigarettes by suitable biomarkers of exposure

G Quantifier ‹ Quantify the uptake of PG and G from e-cigarettes by suitable biomarkers of exposure 3. PG and G uptake Research approach: 13 13 GC-MS analysis of a representative urine sample spiked with IS ( C3-G and C2-PG) ‹ 5 subjects smoked e-cigarettes on one day without nicotine on another day with PG Qualifier nicotine. Individual puffs of e-cigarettes were recorded in a puffing protocol. ‹ 6 urine fractions were collected every 4 – 6 h (over 24 h)

IS PG ‹ 6 saliva samples were collected every 4 – 6 h (over 24 h)

PG Quantifier ‘Vaping behavior’ (average of 5 subjects) Number of vaping sessions: 6 (4 – 8) G Quantifier 4.Comparison between vaping and smoking Duration of session: 15 (10 – 20) min Comparison between vaping and smoking IS G Number of puffs per session: 12 (10 – 15) Conventional E-Cigarettes cigarettes Ratio Total puff number, EC+Nic: 78 (34 – 106) G Qualifier (EC) (CC, 25 (CC/EC) EC – Nic: 91 (66 – 133) smokers) 13 13 Cotinine in saliva (ng/ml) 22.9 240.8 10.5 GC-MS analysis of a representative plasma sample spiked with IS ( C3-G and C2-PG) OH-Cot in saliva (ng/ml) 13.1 53.2 4.1 Conclusion & Outlook Nic+10 (mg/d) 1.05 20.72 19.7 ∆ PG (mg/d) 3.36 0.35 EC with nicotine The application of Biomarkers of Exposure to e-cigarette users (‘vapers’) is possible and also reasonable in order to get reliable dose information. Apart from the exposure to 1.18

∆ PG (mg/d) nicotine, also the exposure to the excipients (PG, G) and flavors can be determined by suitable biomarkers. Background exposure is an issue, which needs to be considered in 7.07 0.17

inhaled dose by suitable biomarkers. Additionally, biomarkers of effect need to be considered in future studies. EC without nicotine the study design. It is of paramount importance to assess the SSPT2015 - Document not peer-reviewed by CORESTA