Chemistry:Nicotine salt

From HandWiki
Nicotine salt
Identifiers
3D model (JSmol)
ChEMBL
EC Number
  • sulfate: 200-606-7
RTECS number
  • sulfate: QS9625000
UNII
UN number 1658
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Nicotine salts are salts formed from nicotine and an acid.[1] They are found naturally in tobacco leaves.[2] Various acids can be used, leading to different conjugate bases paired with the ammonium form of nicotine.

Research

Research on nicotine salts is limited.[3] Possible health risks of persistent inhalation of high levels of nicotine salts are not known.[3] "Juul products use nicotine salts, which can lead to much more available nicotine," Principal Deputy Director Dr. Anne Schuchat of the Centers for Disease Control and Prevention (CDC) stated in September 2019.[4] She also stated that the nicotine salts "cross the blood brain barrier and lead to potentially more effect on the developing brain in adolescents."[4]

Types

A nicotine base and a weak acid such as benzoic acid or levulinic acid is used to form a nicotine salt.[1] Across a sample of 23 nicotine salts available for public purchase, the three most common acids used in the formation of nicotine salts were lactic acid, benzoic acid and levulinic acid.[5] Benzoic acid is the most used acid to create a nicotine salt.[6] Nicotine pyruvate is another form of nicotine salt.[7] A chemical reaction with a pyruvic acid is used to aerosolize nicotine.[8]

Level and rate of delivery

A free-base nicotine solution with an acid reduces the pH, which makes it possible to provide higher levels of nicotine without irritating the throat.[9] Nicotine salts are thought to amplify the level and rate of nicotine delivery to the user. The speed of nicotine salts uptake into the body with the use of electronic cigarettes is close to the speed of nicotine uptake from traditional cigarettes.[10] Traditional cigarettes provide high levels of nicotine, but with the taste of tobacco and paper smoke which many may find undesirable. Pod mods, however, can provide high levels of nicotine without the negative smoking experience.

Nicotine salts are less harsh and less bitter and as a consequence e-liquids that contain nicotine salts are more tolerable even with high nicotine concentrations. Nicotine salts in aerosol form do not generally generate the sensation of irritation in the chest and lungs that regular cigarettes do.[10] Protonated nicotine salt is easier for less experienced users to inhale. This smoother experience of nicotine delivery into the body makes nicotine salts popular amongst those new to vaping e-liquids and those seeking a nicotine replacement therapy that is more commensurate to smoking traditional cigarettes.

As of 2023, many manufacturers in the United Kingdom have been observed to have shifted to nicotine salt-only disposable pods, after previously offering a majority of products in conventional liquids containing freebase nicotine. This is widely seen as being due to nicotine salt's more addictive nature.[11] Nictone salts' more addictive nature has also seen an increase in the uptake of vaping by children.[12]

Brands

The latest generation of e-cigarettes, "pod products," such as Juul, have the highest nicotine content (50 mg/mL), in protonated salt, rather than the free-base nicotine form found in earlier generations.[13] In June 2015, Juul introduced a pod mod device containing nicotine salt.[14] British American Tobacco stated that they have been using nicotine salts in their US Vuse e-liquid brand since 2012.[15]

There has been a proliferation of pod-based products with high nicotine concentration, triggered by Juul's financial success.[6] As of September 2018, there were no less than 39 similar Juul devices as well as 15 Juul-compatible pods being offered.[6] Tested show that the pod mods Juul, Bo, Phix, and Suorin contain nicotine salts in a solution with propylene glycol and glycerin.[3]

Nicotine Salt vaping devices are also available in disposable form, multiple brands exist and since their popularity is rising, many new brands of disposable nicotine salt devices are coming to the market. In the United Kingdom, the maximum nicotine concentration allowed by law is 20mg/ml.[16]

Marketing

Advertisements state nicotine salt liquids contain 2 to 10 times more nicotine than those found in the majority of regular e-cigarette products.[17]

References

  1. 1.0 1.1 "What is the nicotine delivery profile of electronic cigarettes?". Expert Opinion on Drug Delivery 16 (11): 1193–1203. November 2019. doi:10.1080/17425247.2019.1665647. PMID 31495244. 
  2. "The Dangers of Juuling". National Center for Health Research. November 2019. http://www.center4research.org/the-dangers-of-juuling/. 
  3. 3.0 3.1 3.2 "High exposure to nicotine among adolescents who use Juul and other vape pod systems ('pods')". Tobacco Control 28 (6): 676–677. November 2019. doi:10.1136/tobaccocontrol-2018-054565. PMID 30194085. 
  4. 4.0 4.1 LaVito, Angelica; Shama, Elijah (24 September 2019). "CDC warns of dangers of nicotine salts used by vaping giant Juul in e-cigarettes". CNBC. https://www.cnbc.com/2019/09/24/cdc-warns-of-dangers-of-nicotine-salts-used-by-vaping-giant-juul-in-e-cigarettes.html. 
  5. "Characterization of Nicotine Salts in 23 Electronic Cigarette Refill Liquids". Nicotine & Tobacco Research 22 (7): 1239–1243. June 2020. doi:10.1093/ntr/ntz232. PMID 31821492. 
  6. 6.0 6.1 6.2 "Nicotine arms race: JUUL and the high-nicotine product market". Tobacco Control 28 (6): 623–628. November 2019. doi:10.1136/tobaccocontrol-2018-054796. PMID 30733312. 
  7. "New smoking cessation therapy proves promising". American Association for the Advancement of Science. 27 February 2010. https://www.eurekalert.org/pub_releases/2010-02/dumc-nsc022210.php. 
  8. "E-cigarettes: methodological and ideological issues and research priorities". BMC Medicine 13 (1): 32. February 2015. doi:10.1186/s12916-014-0264-5. PMID 25856794. 
  9. "What is new in electronic-cigarettes research?". Current Opinion in Pediatrics 31 (2): 262–266. April 2019. doi:10.1097/MOP.0000000000000741. PMID 30762705. 
  10. 10.0 10.1 "JUUL®: An Electronic Cigarette You Should Know About". American Academy of Family Physicians. 2019. https://www.aafp.org/patient-care/public-health/tobacco-nicotine/tools/e-cigs.html. 
  11. Leventhal, A.M. et al. (2021) ‘Effect of Exposure to e-Cigarettes With Salt vs Free-Base Nicotine on the Appeal and Sensory Experience of Vaping: A Randomized Clinical Trial’, JAMA network open, 4(1), pp. e2032757–e2032757. Available at: https://doi.org/10.1001/jamanetworkopen.2020.32757.
  12. Hammond, D. et al. (2019) ‘Prevalence of vaping and smoking among adolescents in Canada, England, and the United States: repeat national cross sectional surveys’, BMJ (Online), 365, pp. l2219–l2219. Available at: https://doi.org/10.1136/bmj.l2219.
  13. "Electronic Cigarettes and Youth in the United States: A Call to Action (at the Local, National and Global Levels)". Children 6 (2): 30. February 2019. doi:10.3390/children6020030. PMID 30791645.  This article incorporates text by Brian P. Jenssen and Rachel Boykan available under the CC BY 4.0 license.
  14. "Adolescents' and Young Adults' Use and Perceptions of Pod-Based Electronic Cigarettes". JAMA Network Open 1 (6): e183535. October 2018. doi:10.1001/jamanetworkopen.2018.3535. PMID 30646249. 
  15. Rachel Becker (21 November 2018). "Juul's nicotine salts are dominating the market — and other companies want in". The Verge. https://www.theverge.com/2018/11/21/18105969/juul-vaping-nicotine-salts-electronic-cigarettes-myblu-vuse-markten. 
  16. "The Tobacco and Related Products Regulations 2016". https://www.legislation.gov.uk/uksi/2016/507/regulation/36/made. 
  17. "Adolescents' Use of "Pod Mod" E-Cigarettes - Urgent Concerns". The New England Journal of Medicine 379 (12): 1099–1102. September 2018. doi:10.1056/NEJMp1805758. PMID 30134127.