Analysis of Veterinary Hemp-Based Oils for Product Integrity by LC/MS

June 13, 2019
Abstract / Synopsis: 

Pet owners continue to seek alternative therapies for pain relief in their favorite companion animals. Instead of routine nonsteroidal anti-inflammatory drug (NSAID) treatment, there is a trend toward trying hemp-based products rich in cannabinoids. There are increasing numbers of companies producing hemp-based oils enriched with various mixtures of cannabinoids for pain and other maladies including seizures, cancer and anxiety. These products post labels attesting to the composition in the product, usually labeling for cannabidiol (CBD) concentrations in their products. But in the absence of regulatory control we questioned how accurate the information is on the label. The chemical composition of 13 commercially available oils intended for veterinary or a crossover of human and veterinary use was determined by selected ion monitoring liquid chromatography/mass spectrometry (SIM LC/MS). It was found that many of the labels were inaccurate regarding the cannabidiol concentrations and/or the presence of other cannabinoids. In general, the labels on most of the medicinal veterinary samples indicated higher levels of CBD than found in these studies by 20% or more. The precision and accuracy of SIM LC/MS analysis of the samples fell within the acceptable limits of regulated bioanalysis guidelines of +/- 15%.

Many pet owners consider their animals beloved members of the family. When their ‘companion’ is not behaving normally or suffering from pain, they will seek professional help from their favorite veterinarian, and if that is not successful they will sometimes take it upon themselves to treat their ‘best friend’ with other remedies. Although tempting anecdotal reports on the benefits of cannabis- and hemp-based products continue to appear, most veterinarians remain reluctant to recommend cannabis to their clients for several reasons (1). Unfortunately, without proper research, the effects of medications containing CBD on animals remain unknown (2). Foremost is the fact that marijuana and hemp are still considered controlled substances by the U. S. Drug Enforcement Administration (DEA). The American Veterinary Medical Association considers them illegal depending on the state laws, and discourages veterinarians from prescribing them for pets.

Although not currently considered pharmaceutical agents per se, there is clearly a lot of interest in the role that marijuana and hemp and their derived products may have in veterinary healthcare. Increasingly, pet owners have already experimented with advertised medicinal cannabis products. These include oils reportedly containing therapeutic levels of CBD, in addition to other ingredients with product claims of beneficial effects. In states where recreational cannabis is legal, veterinarians are seeing increasing incidences of toxic cannabis cases in dogs. These popular companion animals have indiscriminate eating habits and often eat discarded cannabis products. In addition, veterinarians have had to respond to the pet owners’ queries regarding the pros and cons associated with the proper use of medicinal cannabis. Since there is very little research to-date on these topics, veterinarians are often limited on their ability to wisely respond to these queries.

Medicinal marijuana, or medicinal cannabis, is a treatment regimen that has attracted considerable national attention recently (3). Controversy continues surrounding the legal, ethical, and societal implications associated with its use. Issues include safe administration, adverse health consequences and reported deaths attributed to marijuana intoxication. Therapeutic indications are based on limited clinical data and represent some of the complexities associated with this treatment. Cannabis indica or Cannabis sativa are considered marijuana or hemp. Regardless of what it is called, cannabis is currently considered by the DEA Comprehensive Drug Abuse Prevention and Control Act (Controlled Substances Act) of 1970 as a Schedule I controlled substance. This definition suggests cannabis has a high potential for abuse, no currently accepted medicinal use in treatment in the United States, and a lack of accepted safety data for use of the treatment under medical supervision (4). There is a dearth of research in support of its safety or therapeutic value in clinical settings.

Marijuana and hemp have been used medicinally worldwide for thousands of years (5). In the early 1990s, the discovery of cannabinoid receptors in the central and peripheral nervous systems created interest in other potential therapeutic values of marijuana (6). Since then, marijuana has been used by patients experiencing chemotherapy-induced anorexia, nausea and vomiting, pain, and forms of spasticity. Use among patients with glaucoma and human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) has also been widely reported (7). It should not be surprising that veterinarians may be interested in the potential for medicinal cannabis to relieve pain and other clinical issues associated with their animal patients (8,9).

The historically restrictive legal guidelines for cannabis have significantly limited research on its safety and efficacy in both humans and animals (10). However, a recent study by researchers at the Cornell University College of Veterinary Medicine reported on the potential beneficial effects of CBD oils administered orally to osteoarthritic (OA) dogs (11). A representative commercial veterinary medicinal CBD oil was purchased and administered orally in the food of known OA canine patients. The publication described the pharmacokinetics, safety and clinical efficacy of cannabidiol treatment in osteoarthritic dogs, which suggested that a 2 mg/kg of CBD twice daily can help increase comfort and activity in dogs with this condition.

These findings spurred us to examine whether the selected 13 commercial oils were similar in chemical composition. In this report, we describe the chemical analysis of some representative commercial veterinary oils by SIM LC/MS to determine the concentration of the constituents reported on the labels of those products.

This analytical approach is one of several available for such an application as described in a recent review (12). We also monitored common other cannabinoid constituents which were not listed on some of the product labels. There are an ever-increasing number of suppliers of such oils and related products which are sold in the absence of any regulatory control.

The goal of this study was to compare our analysis results on the cannabinoid composition with the indicated concentrations of selected compounds on the product label. A recent report on phytocannabinoids common to the cannabis cultivars present in medicinal oils for human use was reported, where high-performance liquid chromatography/ultraviolet detection (HPLC/UV) analyses were described (13). The report described herein expands upon hemp oil analysis with a focus on commercially available oils intended for pet consumption using the more sensitive and selective analytical capabilities of SIM LC/MS.


  1. D. Vaughan, Am. Vet. 2(2) (2017).
  2. A. Carrozza, “Medical Marijuana Research Remains Top Priority for Veterinarians American Veterinarian” (2018)
  3. B. Halford, Chemical & Engineering News, 96(30), 28-33 (2018).
  4. M.B. Bridgeman, and D.T. Abazia, P&T 42 (3),180-188 (2017).
  5. S. Faraq, and O. Kayser, Chapter 1 The Cannabis Plant: Botanical Aspects (Elsevier, 2017).
  6. A. Hazekamp, and J.T. Fischedick, Drug Test Anal 4(11), 660-667 (2011).
  7. R.G. Pertwee, Handbook of Cannabis (Oxford University Press, New York, 2014).
  8. L. Parshley, and D. Mensching, Washington Veterinarian May/June 10(6), 14-18 (2014).
  9. C. Gyles, The Canadian Veterinary Journal  57(12), 1215 (2016).
  10. C.M. Andres, J. F. Hausman, and G. Guerriero, Front. Plant Sci. 7 (19), 1-17 (2016).
  11. L.J. Gamble, J.M. Boesch, C.W. Freye, W.S. Schwark, S. Mann, L. Brown, E.S. Berthelsen, and J.J. Wakshlag, Frontiers in Veterinary Science 5(165), 1-9 (2018).
  12. A. Leghissa, Z.L. Hildenbrand, and K.A. Schug, J. Sep. Sci. 41(1), 398-415 (2018).
  13. C. Young, and B. Clifford, Cannabis Sci Tech. 1(2), 38-43 (2018).
  14. Q. Meng, B. Buchanan, J. Zuccolo, M.M. Poulin, J. Gabriele, and D.C. Baranowski, PLoS One 13 (5), 1-16 (2018).
  15. M.A. Elsohly, and D. Slade, Life Sci, 78(5), 539-48 (2005).
  16. C. Giroud, Chemia, 56 (3), 80-83 (2002).
  17. U.S. Food and Drug Administration (FDA) “FDA approves first drug comprised of an active ingredient derived from marijuana to treat rare, severe forms of epilepsy.


Ben Nie is a Scientist and Jack Henion, PhD, is Cofounder and Chief Science Officer at Advion Inc. Joe Wakshlag, PhD, is with the College of Veterinary Medicine, University of Florida. Direct correspondence to: [email protected]; [email protected].


How to Cite This Article:

Nie B et al., Cannabis Science and Technology 2(3), 36-45 (2019)