E-Cigarettes: A Review of New Trends in Cannabis Use

Abstract

The emergence of electronic cigarettes (e-cigs) has given cannabis smokers a new method of inhaling cannabinoids. E-cigs differ from traditional marijuana cigarettes in several respects. First, it is assumed that vaporizing cannabinoids at lower temperatures is safer because it produces smaller amounts of toxic substances than the hot combustion of a marijuana cigarette. Recreational cannabis users can discretely "vape" deodorized cannabis extracts with minimal annoyance to the people around them and less chance of detection. There are nevertheless several drawbacks worth mentioning: although manufacturing commercial (or homemade) cannabinoid-enriched electronic liquids (e-liquids) requires lengthy, complex processing, some are readily on the Internet despite their lack of quality control, expiry date, and conditions of preservation and, above all, any toxicological and clinical assessment. Besides these safety problems, the regulatory situation surrounding e-liquids is often unclear. More simply ground cannabis flowering heads or concentrated, oily THC extracts (such as butane honey oil or BHO) can be vaped in specially designed, pen-sized marijuana vaporizers. Analysis of a commercial e-liquid rich in cannabidiol showed that it contained a smaller dose of active ingredient than advertised; testing our laboratory-made, purified BHO, however, confirmed that it could be vaped in an e-cig to deliver a psychoactive dose of THC. The health consequences specific to vaping these cannabis preparations remain largely unknown and speculative due to the absence of comprehensive, robust scientific studies. The most significant health concerns involve the vaping of cannabinoids by children and teenagers. E-cigs could provide an alternative gateway to cannabis use for young people. Furthermore, vaping cannabinoids could lead to environmental and passive contamination.

Keywords: adolescence; cannabis; electronic cigarette; vaping.

Figure 1

Microprocessor-controlled, variable-voltage/wattage, personal electronic-cigarette with LED digital display (volts or watts, puff count, ohmic resistance), equipped with a transparent clearomizer and changeable dual-coil head. Vaping cannabis requires an e-cigarette model of this type, offering a wide range of settings (power, voltage adjustments) and the option of using different resistance coils. The presence, number, and positioning of wicks are also important.

Figure 2

Some models of e-cigs for vaping (a) ground marijuana head tops; (b) cannabis wax (butane honey oil concentrate (BHO)), or (c) cannabis e-liquid. The letters a, b, or c after the numbers indicate the parts of e-cigs used for herb, BHO, or e-liquid vaping, respectively. 1. Mega electronic cigarette (e-cig) with dual-coil clearomizer, adjustable airflow control ring, changeable resistance coils and high capacity, variable voltage battery. 2–7. Dry herb and wax vaporizer: 2. Spring-loaded mouthpiece; 3. Vaporizer chamber; 4. Dry herb coil head; 5. Wax coil head; 6. Detachable base with air holes; 7. Medium capacity battery. 8–10. See-through clearomizer for e-liquids: 8. Clearomizer tip; 9. Clearomizer tube; 10. Clearomizer coil and four-wick head with base assembly. 11–14. Glass-globe atomizer wax tank: 11. Drip tip; 12. Glass globe; 13. Ceramic heating chamber and coil; 14. Metal core. 15–19. Dry herb atomizer: 15. Soft drip tip (mouthpiece); 16. Ceramic screen; 17. Metal screen and spring; 18. Screens connector; 19. Ceramic chamber and battery connector. 20. Medium size battery. 21–22. Wax coil head atomizer: 21. Metal mouthpiece and wax coil chamber connector; 22. Wax coil ceramic chamber and battery connector. 23–25. Clearomizer for e-liquids: 23. Shell (mouthpiece attached to metal tank with viewing window); 24. Bottom head changeable coil assembly; 25. Battery base connector. a. Marijuana head tops, b. Cannabis Butane Honey Oil concentrate (BHO), c. Cannabis e-liquid (mixture of cannabinoid concentrates (cannabis wax), propylene glycol and glycerol).

Figure 3

Manufacture of ground cannabis head buds, butane honey oil extract and cannabis e-liquid. 1–3. Processing cannabis heads and smoking them in a dry herb vaporizer; 4–9. Manufacture of cannabis oil concentrate and vaping with a wax vaporizer; 10–11. Making a cannabis e-liquid and vaping in a regular e-cigarette or e-mod.

Figure 4

Gas chromatography-mass spectrometry (GC-MS) chromatograms of TMS derivatives of an EJMIX extract and of a BHO/EJMIX 35:65 w/w solution. EJMIX is a commercially available mixture of propylene glycol (PG) and polyethylene glycol (PEG) molecules in unknown proportions (Bloomsdays, USA). The PEG molecules are characterized by their number, n, of “oxyethylene” units. PEG 200 usually contains 4–5 units; PEG 300, 6–7 units; and PEG 400, 8–9 units. PG is propylene glycol or 1,2-propane diol. THC = (−)-trans-delta-9-tetrahydrocannabinol; CBN = cannabinol. C16:0 and C18:0 are palmitic and stearic acids, respectively.