The Importance of Synthetic Nicotine Testing for ENDS, Vape and Smokeless Tobacco Products

Two sources of nicotine, natural nicotine, obtained from a plant source (by and large from tobacco plants), and synthetic nicotine, which is produced via chemical synthesis, are being incorporated into vape and smokeless tobacco products.

Synthetic nicotine, also known as tobacco-free nicotine (TFN), is synthesized using an assortment of chemicals including sulfuric acid, niacin and ethanol. The distinction between natural and synthetic nicotine is critically important within the vaping industry, as the definition of nicotine, which includes its source, has a direct correlation to the oversight, or lack thereof, of the US Food and Drug Administration (FDA) for e-liquids and electronic nicotine delivery systems (ENDS).

Although synthetic nicotine has the same molecular formula as natural nicotine, there is much debate and some uncertainty about whether synthetic nicotine will ultimately be regulated under FDA’s vaping policies and the premarket tobacco product application (PMTA) guidance. At present, products containing synthetic nicotine products appear to fall into a regulatory gap, as they seemingly do not fit within the definition of a tobacco product as detailed within the Federal Food, Drug, and Cosmetic Act (FDCA). Moreover, the FDA has defined nicotine as any nicotine “made or derived from tobacco,” which ostensibly presents a regulatory loophole for nicotine which has not been obtained from the tobacco plant, keeping synthetic nicotine outside the reach of current regulations.

It is worth noting there is speculation that the FDA may potentially regulate synthetic nicotine as a drug under the FDCA, but to do so, the Agency must be able to demonstrate that the product is “intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease” or “intended to affect the structure or any function of the body…” In the event that the FDA were able to regulate synthetic nicotine products as drugs, the Agency would be able to regulate products containing synthetic nicotine products similarly to the way in which the FDA currently handles natural, tobacco-derived nicotine products. Currently, when nicotine serves a therapeutic use, it is considered to be a pharmaceutical, and therefore is regulated by the FDA accordingly. An example of this is the use of nicotine in smoking cessation products (e.g., nicotine patches).

The benefits and disadvantages of synthetic nicotine

While the current regulatory loophole is viewed as the principal advantage for incorporating synthetic nicotine into e-juice products by many manufacturers of ENDS, vape and smokeless tobacco products, synthetic nicotine also offers a wide range of additional benefits, with the absence of taste and odor being one of the most significant. Many users of vape products believe the taste-free attribute of synthetic nicotine results in a better, more pleasurable overall vaping experience, as a cleaner flavor is produced when synthetic nicotine is incorporated into vape products. Furthermore, when synthetic nicotine is used in ENDS and nicotine-containing products, the impurities associated with natural tobacco can be completely removed, along with the risks these impurities present to those who vape and consume nicotine-containing products. These harmful impurities can include pesticides, tobacco specific nitrosamines (TSNAs), and microbial toxins, such as mycotoxins. The applications for synthetic nicotine extend beyond vape and ENDS products, and synthetic nicotine can be incorporated into smokeless nicotine-containing products, including pouches, lozenges, gums, and novel reduced-risk product platforms.

Manufacturers of ENDS, e-liquid and smokeless nicotine-containing products considering swapping out natural nicotine for tobacco-free nicotine will need to contemplate the increased costs associated with synthetic nicotine, in addition to a lack of available safety data. When compared to the costs associated with natural nicotine derived from tobacco plants, the price of synthetic nicotine is considerably higher, and as a result, consumers may be paying more for vape products which contain synthetic nicotine. Moreover, there are several unknowns regarding the safety of synthetic nicotine and its long-term effects on those who vape and consume products formulated with tobacco-free nicotine, as scientific studies regarding health effects and product safety, including toxicological assessments, have been performed on natural nicotine, rather than lab-derived, synthetic nicotine.

Lab testing can determine whether synthetic nicotine is present in ENDS and e-liquid products

Finished nicotine, smokeless tobacco, vape and ENDS products on the market, as well as the raw materials used in the creation of those products, can be analyzed to determine whether the nicotine contained within the product has been derived from a synthetic source. There appears to be a consensus as to which analytical tests are needed to confirm whether nicotine is synthetic or naturally derived, including:

Nicotine isomer optical rotation testing

The ratio of R- and S-stereo isomers are at the core of the primary chemical differences between synthetic and natural nicotine, as well as laboratory testing. Though only the S-stereo isomer is fully metabolized and absorbed by the consumer, tobacco-free, synthetic nicotine is a mixture of both R- and S-stereo isomers of nicotine. On the other hand, natural nicotine consists only of S-stereo isomer. Typically, in synthetic, tobacco-free nicotine, there is a 1:1 ratio of R- and S-stereo isomers. R-stereo isomers have a positive optical rotation, whereas S-stereo isomers have a negative optical rotation. In the 1:1 ratio indicative of synthetic nicotine, the result is no observable optical rotation, as the positive and negative optical rotation of the isomers cancel one another out. If optical rotation is observed, scientists may conclude that the nicotine is either a mix of synthetic and natural nicotine, or the nicotine present in the e-liquid product has been derived from a natural source. Even if the product tested contains a blend of natural and synthetic nicotine, due to the presence of natural nicotine in either of the previously described scenarios, the product would be subject to FDA oversight, and consequently, must comply with the PMTA regulatory pathway.

Additional confirmatory analyses may be pursued by scientists, including the use of chiral HPLC to separate the R- and S-stereo isomers within the nicotine with a chiral column. Once separated, the relative amounts of each isomer can be detected, and a determination can be made as to whether the nicotine being analyzed is naturally derived or synthetic.

Testing of nicotine for the presence of tobacco specific nitrosamines (TSNAs)

Synthetic nicotine is inherently free from tobacco-specific impurities, including tobacco specific nitrosamines (TSNAs), as it is created by means of chemical synthesis. Tobacco specific nitrosamines are some of the most potent carcinogens found in tobacco products. TSNAs are generated during the curing and processing of naturally derived tobacco as a result of a nitrosation reaction, which converts organic compounds into nitroso derivatives. Two of the eight identified TSNAs have been classified as Group 1 cancer-causing carcinogens, N-nitrosonornicotine (NNN) and 4-methyl-N-nitrosamino-1-(3-pyridyl)-1-butanone (NNK). Liquid chromatography mass spectrometry (LC-MS) instrumentation and analytical methodology can be employed to quantify tobacco specific nitrosamines in nicotine and nicotine-containing products. An LC-MS method has been developed and validated by Element’s team of expert scientists to quantitate four tobacco specific nitrosamines, specifically NAB, NAT, NNN, and NNK, in nicotine-containing products.

When nicotine-containing products and/or the nicotine itself is analyzed by a validated method for TSNAs, the confirmed absence or presence of TSNAs, in combination with the results of optical rotation testing, can verify whether nicotine has been derived from a natural source or chemical synthesis.

Purity testing of synthetic nicotine

Even though purity testing is not a requirement when determining whether nicotine is synthetic or natural, an understanding of the purity of nicotine can provide important insight as to the composition and quality of a product. The American e-Liquid Manufacturing Standards Association (AEMSA) calls for the incorporation of US Pharmacopeia (USP) grade nicotine in their e-liquid products. USP specifications of nicotine purity allow for a maximum of 0.5% (5 mg/g) of a single impurity and 1.0% (10 mg/g) total impurities. Although these standards are widely accepted within the industry, it is important to note that the AEMSA possesses no regulatory authority.

Nicotine compounds are extracted from tobacco plants by means of a rigorous process that relies upon several chemicals, solvents, and extractions. Alternatively, a multi-step synthetic manufacturing protocol is followed to create synthetic nicotine, building upon ethyl nicotinate which serves as a backbone that different compounds of low or moderate toxicity are added to as a result of various chemical reactions. Due to the way in which it is synthesized and manufactured, synthetic nicotine has limited impurities and can be scaled without the needs of farms, crops, or extraction processes.

Choosing the right laboratory for synthetic (TFN) and natural nicotine testing

Multiple factors must be considered when choosing the right lab to partner with for nicotine product testing, including whether that lab is FDA-registered. While not all labs that perform nicotine testing are registered with the FDA, all tobacco products are regulated by the FDA, including products which contain naturally derived nicotine. Element’s consultative team of scientists is standing by ready to support your nicotine testing needs in our purpose-built, FDA-registered lab. Our scientists will act as a true extension of your team, providing industry-leading insight and perspective, as well as access to a wealth of scientific and legal knowledge. Our approach is customized to each individual customer and their needs, providing fit-for-purpose solutions.