Development, validation, and application of an LC-MS/MS method for mitragynine and 7-hydroxymitragynine analysis in hair

Development of a CZE-MS/MS method with dynamic pH junction sample pretreatment for analysis of kratom psychoactive alkaloids in urine

BACKGROUND

Kratom is a herbal substance belonging to the group of new psychoactive substances. It contains psychoactive indole alkaloids mitragynine and 7-hydroxymitragynine. At low doses, they act as psychostimulants and at higher doses they mediate an opioid-like effect. The increasing misuse of kratom requires the development of analytical methods that will accurately and reliably identify and quantify its psychoactive alkaloids in biological samples. Therefore, the development of effective, precise, and reliable green analytical methods that are easy to implement in practice is of great importance. On-line combination of capillary zone electrophoresis with tandem mass spectrometry (CZE-MS/MS) seems to be a promising solution.

RESULTS

We present a novel green approach based on capillary zone electrophoresis - tandem mass spectrometry (CZE-MS/MS) method with on-line dynamic pH junction sample pretreatment to identify and determine mitragynine and 7-hydroxymitragynine in urine samples. The separation was performed in a background electrolyte composed of 100 mM formic acid (pH 2.39). The dynamic pH junction was ensured by injection of a short plug of 12.5 % NH4OH before the sample. Under optimal conditions, the developed method was validated and parameters such as linearity (r2 > 0.99), precision (2.2-8.7 %), accuracy (89.2-102.5 %) or stability of the sample (86.6-114.7 %) met the defined FDA guideline criteria (%RSD and %RE values where within ±15 %). Introduction of a simple in-capillary preconcentration strategy based on dynamic pH junction enabled significant improvement in analytical signal intensity and also the applicability of the method. Applying the presented approach, high sensitivity was achieved as indicated by limit of detection values, which were 0.5 ng mL-1 and 2 ng mL-1 for mitragynine and 7-hydroxymitragynine, respectively. Greenness of the proposed approach was confirmed by the AGREE metrics (score 0.63). The application potential of the developed method was successfully verified using blinded urine model samples.

SIGNIFICANCE

For the first time a fully validated CZE-MS/MS method for kratom alkaloids determination was introduced. The presented novel method is a cheaper and more ecological alternative to conventionally used chromatographic techniques what was clearly confirmed by its greenness evaluation and comparison with previously published liquid chromatography (LC) approaches. In-capillary sample pretreatment (dynamic pH junction) has been demonstrated to be an effective and fast tool in bioanalysis, minimizing the number of pretreatment steps and the manipulation with the sample. Moreover, LOD values comparable to those obtained by LC methods were recorded. High potential for the implementation of this approach into the toxicology environment in the near future is expected.

LC-MS-MS method for mitragynine and 7-hydroxymitragynine in hair and its application in authentic hair samples of suspected kratom abusers

Kratom is a natural psychoactive product known primarily in Southeast Asia, including Thailand, Malaysia, etc. It is also known as krathom, kakuam, ithang, thom (Thailand), biak-biak, ketum (Malaysia) and mambog (Philippines) and is sometimes used as an opium substitute. It is stimulant at doses of 1-5 g, analgesic at doses of 5-15 g and euphoric and sedative at doses of >15 g. Mitragynine is the most abundant indole compound in kratom (Mitragyna speciosa) and is metabolized in humans to 7-hydroxymitragynine, the more active metabolite. Adverse effects include seizures, nausea, vomiting, diarrhea, tachycardia, restlessness, tremors, hallucinations and death. There are few studies on the analytical method for the detection of mitragynine and 7-hydroxymitragynine in hair. Therefore, this study proposes a liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the analysis of kratom in hair. Hair samples were first weighed to ∼10 mg and washed with methanol. Then the washed hair samples were cut into pieces and incubated in methanol with stirring and heating (16 h/38℃). Extracts were then analyzed by LC-MS-MS. This method was validated by determining the limit of detection (LOD), limit of quantification, linearity, intra- and inter-day accuracy and precision, recovery and matrix effects. The intra- and inter-day precision (CV%) and accuracy (bias%) were within ±20%, which was considered acceptable. Using this newly developed LC-MS-MS method, the simultaneous detection of mitragynine and 7-hydroxymitragynine in six authentic hair samples was achieved to provide the direct evidence of kratom use in the past. Mitragynine concentrations ranged from 16.0 to 2,067 pg/mg (mean 905.3 pg/mg), and 7-hydroxymitragynine concentrations ranged from 0.34 to 15 pg/mg (mean 7.4 pg/mg) in six authentic hair samples from kratom abusers. This may be due to the higher sensitivity of the LOD in this study, with values of 0.05 pg/mg for mitragynine and 0.2 pg/mg for 7-hydroxymitragynine in hair.

Testing for Kratom alkaloids in fingernail clippings - not only mitragynine

Kratom (Mitragyna speciosa) is a species of large tree that grows in Southeast Asia and is part of the Rubiaceae family. Its fresh leaves are harvested for their medicinal properties and used for their psychoactive effects. Kratom contains many biologically active alkaloids, including mitragynine and 7-OH-mitragynine, which are considered the two most important psychoactive components and constitute approximately 66% and 2% of the total alkaloid content. Other alkaloids are present in the plant, such as speciogynine, speciociliatine and paynantheine, but have less psychoactive activity. Over the past decade, the sale of kratom powder has increased on the Internet. This led to a significant increase in forensic cases. Given the lack of data existing in the literature, and the total absence of data in nails, the authors report a study to determine the best target alkaloids for documenting kratom consumption in this matrix. Fingernail clippings from a supposed kratom powder user were analyzed after liquid-liquid extraction, chromatography separation using a HSS C18 column and performed on an ultra-high performance liquid chromatography coupled to a tandem mass spectrometer. In the specimen, mitragynine was quantified at 229 pg/mg, speciogynine and paynantheine were both quantified at 2 pg/mg, and speciociliatine was quantified at 19 pg/mg. 7-OH-mitragynine was not detected. The interpretation of these concentrations is complex, since there is currently no reference in the literature, as this is the first identification of mitragynine and other kratom alkaloids in nails. Nevertheless, in view of the high concentration of mitragynine, the subject seems to be a repetitive user of kratom. According to the measured concentrations, it seems that mitragynine remains the best target to document kratom consumption, but the identification of the other alkaloids would enhance the specificity of the test.

[Kratom (Mitragyna Speciosa): a Psychoactive Plant with Opportunities and Risks]

Kratom is an evergreen tree that is native to Southeast Asia. Its leafs are traditionally used as a stimulant, a remedy for various health problems and for religious purposes. Especially in the US (in a lesser extent also in Europe) kratom use is significantly prevalent. In Western countries, kratom is used predominantly as an analgesic and stimulant, for the treatment of opioid use disorders, and for improving mental health (e. g., in depression, anxiety disorders). Main molecular constituents of kratom are alkaloids of which mitragynine and 7-hydroxymitragynine appear to be most important. Pharmacodynamics and -kinetics of kratom are complex and insufficiently studied. It is known that mitragynine and 7-hydroxymitragynine are partial agonist at human μ-opioid receptors and antagonists at κ- and δ-opioid receptors with additional effects at other central receptors. Tolerability of kratom is presumably better than that of classical opioids; this is probably due to missing effects of kratom on β-arrestin and discussed as a starting point for the development of opioids with improved tolerability. Some alkaloids of kratom are inhibitors of CYP26 and to a somewhat lesser degree of CYP2C19 and CYP3A4. The addictive potential of kratom appears to be lower than that of classical opioids; however, corresponding data is limited and kratom use disorders appear to occur primarily in Western countries. Several cases of severe health-related problems and deaths are known in the US; in these cases, however, polysubstance use was usually present. Kratom use is likely associated with hepatotoxicity and cardiotoxicity. Kratom-associated mortality and morbidity in Western countries are quantitatively significantly different from Southeast Asia, where kratom use is no public health problem. The reasons for this may be the combined use of substances (which is more prevalent in Western countries), higher dosages of consumed kratom, adulterations and contaminations of commercially available kratom in Western countries, pharmacokinetic interactions, and higher concentrations of 7-hydroxymitragynine in dried kratom leafs (that are typically consumed in Western countries) in comparison to fresh leafs (that are typically consumed in Southeast Asia).

Kratom: The analytical challenge of an emerging herbal drug

Mitragyna speciosa or kratom is emerging worldwide as a "legal" herbal drug of abuse. An increasing number of papers is appearing in the scientific literature regarding its pharmacological profile and the analysis of its chemical constituents, mainly represented by alkaloids. However, its detection and identification are not straightforward as the plant material is not particularly distinctive. Hyphenated techniques are generally preferred for the identification and quantification of these compounds, especially the main purported psychoactive substances, mitragynine (MG) and 7-hydroxymitragynine (7-OH-MG), in raw and commercial products. Considering the vast popularity of this recreational drug and the growing concern about its safety, the analysis of alkaloids in biological specimens is also of great importance for forensic and toxicological laboratories. The review addresses the analytical aspects of kratom spanning the extraction techniques used to isolate the alkaloids, the qualitative and quantitative analytical methods and the strategies for the distinction of the naturally occurring isomers.

Analysis of Mitragynine and Speciociliatine in Umbilical Cord by LC-MS-MS for Detecting Prenatal Exposure to Kratom

Kratom is an herbal drug that is legal in the USA. While it is marketed as a safer alternative to opioids, it can cause opioid-like withdrawal symptoms when discontinued after regular use. Several case studies have shown that kratom exposure in utero can lead to symptoms in newborns consistent with neonatal abstinence syndrome. Here, we present a validated method for the detection of kratom in umbilical cord by liquid chromatography--tandem mass spectrometry. The umbilical cord is homogenized in solvent and kratom analytes are purified by solid phase extraction (strong cation exchange). Diastereomeric kratom alkaloids mitragynine (MG), speciociliatine (SC), speciogynine and mitraciliatine are separated by reverse phase chromatography on a phenyl-hexyl column. Applying this method to residual umbilical cords submitted to our laboratory for drug testing, 29 positive specimens exhibiting varied kratom analyte distributions were observed. MG and SC were the most abundant kratom analytes and were selected as biomarkers of kratom exposure. A cutoff concentration of 0.08 ng/g was established for both MG and SC.

Clinical Pharmacology of the Dietary Supplement, Kratom (Mitragyna speciosa)

Kratom (Mitragyna speciosa) consists of over 40 alkaloids with two of them, mitragynine (MG) and 7-OH-mitragynine (7-OH-MG) being the main psychoactive compounds. MG and 7-OH-MG each target opioid receptors and have been referred to as atypical opioids. They exert their pharmacologic effects on the μ, δ, and κ opioid receptors. In addition, they affect adrenergic, serotonergic, and dopaminergic pathways. Kratom has been touted as an inexpensive, legal alternative to standard opioid replacement therapy such as methadone and buprenorphine. Other uses for kratom include chronic pain, attaining a "legal high," and numerous CNS disorders including anxiety depression and post-traumatic stress disorder (PTSD). Kratom induces analgesia and mild euphoria with a lower risk of respiratory depression or adverse central nervous system effects compared to traditional opioid medications. Nonetheless, kratom has been associated with both physical and psychological dependence with some individuals experiencing classic opioid withdrawal symptoms upon abrupt cessation. Kratom use has been linked to serious adverse effects including liver toxicity, seizures, and death. These risks are often compounded by poly-substance abuse. Further, kratom may potentiate the toxicity of coadministered medications through modulation of cytochrome P450, P-glycoprotein, and uridine diphosphate glucuronosyltransferase enzymes (UGDT). In 2016 the U.S. Drug Enforcement Administration (DEA) took steps to classify kratom as a federal schedule 1 medication; however, due to public resistance, this plan was set aside. Until studies are conducted that define kratom's role in treating opioid withdrawal and/or other CNS conditions, kratom will likely remain available as a dietary supplement for the foreseeable future. This article is protected by copyright. All rights reserved.