Evaluation of a hapten conjugate vaccine against the "zombie drug" xylazine.

Xylazine has emerged as a primary adulterant in fentanyl, exacerbating the complexity of the opioid crisis. Yet, there is no approved drug that can reverse xylazine's pathophysiology. As a prelude to monoclonal antibodies being assessed as a viable therapeutic, a vaccine inquiry was conducted evaluating the immune response in reversing xylazine induced behavior effects.

Highly Sensitive Voltammetric Sensor Using Carbon Nanotube and an Ionic Liquid Composite Electrode for Xylazine Hydrochloride.

Electrochemical techniques were used for estimating xylazine HCl (XLZ) in bulk powder, medicinal manufacturing and human serum. Electro-oxidation of XLZ at carbon multiwalled nanotube (MWCNT), 1-n-butyl-3-methylpyridinium hexafluorophosphate ion crystal (BMH) and sodium dodecyl sulfate (SDS) MWCNT-BMH-SDS electrode in 0.04 M Britton-Robinson buffer (BR) with pH 7.0, was studied in numerous buffer structures and at different pH values. The experimentation and instrumental parameters to assessable commitment of XLZ had been optimized, and a detection limit was observed as 4.80 nM. The precision and accuracy for the recognized method was tested by retrieval studies with good repeatability and reproducibility of the estimated method. The projected method was practiced successfully to the dosage form and spiked serum.

Toward Higher Sensitivity in Quantitative MALDI Imaging Mass Spectrometry of CNS Drugs Using a Nonpolar Matrix.

Tissue-specific ion suppression is an unavoidable matrix effect in MALDI mass spectrometry imaging (MALDI-MSI), the negative impact of which on precision and accuracy in quantitative MALDI-MSI can be reduced to some extent by applying isotope internal standards for normalization and matrix-matched calibration routines. The detection sensitivity still suffers, however, often resulting in significant loss of signal for the investigated analytes. An MSI application considerably affected by this phenomenon is the quantitative spatial analysis of central nervous system (CNS) drugs. Most of these drugs are low molecular weight, lipophilic compounds, which exhibit inefficient desorption and ionization during MALDI using conventional polar acidic matrices (CHCA, DHB). Here, we present the application of the (2-[(2 E)-3-(4- tert-butylphenyl)-2-methylprop-2-enylidene]malononitrile) matrix for high sensitivity imaging of CNS drugs in mouse brain sections. Since DCTB is usually described as an electron-transfer matrix, we provide a rationale (i.e., computational calculations of gas-phase proton affinity and ionization energy) for an additional proton-transfer ionization mechanism with this matrix. Furthermore, we compare the extent of signal suppression for five different CNS drugs when employing DCTB versus CHCA matrices. The results showed that the signal suppression was not only several times lower with DCTB than with CHCA but also depended on the specific tissue investigated. Finally, we present the application of DCTB and ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry to quantitative MALDI imaging of the anesthetic drug xylazine in mouse brain sections based on a linear matrix-matched calibration curve. DCTB afforded up to 100-fold signal intensity improvement over CHCA when comparing representative single MSI pixels and >440-fold improvement for the averaged mass spectrum of the adjacent tissue sections.

Analysis of ketamine and xylazine in complex matrices using two-dimensional liquid chromatography/tandem mass spectrometry.

RATIONALE: Analyzing tissue samples is routinely performed when liquid biological samples are not available for replicate analysis. Preparing complex matrices, such as tissue, for analysis can be time-consuming. Traditional sample preparation methods typically begin with homogenization followed by a sample clean-up step such as liquid-liquid or solid-phase extraction. Samples are typically eluted, evaporated and reconstituted prior to instrumental analysis. The aim of this project was to evaluate the utility of multi-dimensional chromatography in reducing the amount of time from sample acquisition to analysis. METHODS: Tissue specimens were homogenized using a ceramic beads shaker. Homogenates were then diluted and loaded onto a mixed mode solid-phase sorbent. The sorbent was washed, and the final eluate was transferred directly to vials without evaporation or reconstitution steps. Analysis was performed using a two-dimensional (2D) ultra-performance liquid chromatography (UPLC) configuration with an At-column dilution option coupled to a triple quadrupole mass spectrometer. The target analytes (xylazine and ketamine) were quantified under multiple reaction monitoring (MRM) using electrospray ionization (ESI) in positive mode. RESULTS: The lowest limit of detection evaluated in this study was 0.01 ng/mL. The linear dynamic range utilized was 0.1 to 10 ng/mL. The concentrations for xylazine in their respective tissues ranged from 0 to 0.316 ng/mL. Ketamine concentrations ranged from 0 to 0.905 ng/mL. The overall time for sample preparation was reduced to 30 min. The total run time was 10 min. CONCLUSIONS: The use of multidimensional chromatography with At-column-dilution allows for significant reduction in sample preparation time. The concentrations determined in these samples highlight the need for sensitive analytical techniques with the ability to detect analyte concentrations at sub ng/mL.

Chemical stability of morphine and methadone, and of methadone in combination with acepromazine, medetomidine or xylazine, during prolonged storage in syringes.

OBJECTIVE: To assess the chemical and physical stability of morphine and methadone stored in syringes for 12 months and of methadone when mixed with acepromazine, medetomidine or xylazine. METHODS: A high-performance liquid chromatography (HPLC) technique was developed and validated for the analysis of morphine and methadone. Morphine and methadone were dispensed into syringes and stored at 25°C/60% relative humidity (RH) and 40°C/75% RH. Solutions containing mixtures of methadone combined with acepromazine, medetomidine or xylazine were stored in syringes at 25°C/60%RH. At initiation, after 1 week and then 1, 3, 6, 9 and 12 months, samples were analysed by HPLC for the quantification of the morphine or methadone. Measured concentrations were assessed as a function of storage time and temperature using linear regression statistics to calculate stability. RESULTS: When stored at 40°C/75%RH as pre-dispensed syringes, severe physical and chemical changes were observed after the third month for both morphine and methadone. In contrast, at 25°C/60%RH both drugs remained chemically stable for 12 months, with concentration variations not exceeding a 5% change from initiation as stipulated in VICH stability guidelines. When in combination with acepromazine or xylazine, methadone also remained chemically stable, but the combination with medetomidine failed stability criteria prior to 6 months. Precipitation compromised the physical stability of methadone in all unsealed syringes prior to 9 months' storage. CONCLUSION: Pre-dispensing morphine or methadone into unsealed syringes compromises the drugs' physical stability. Mixing of methadone with other drugs can degrade its chemical stability.

Assessment of stability of ketamine-xylazine preparations with or without acepromazine using high performance liquid chromatography-mass spectrometry.

The objective of this study was to evaluate the stability of 3 distinct preparations of ketamine and xylazine, with or without acepromazine, stored at room temperature or at 4°C for 1, 2, and 3 mo. Drug concentrations were compared to fresh solutions, using a high performance liquid chromatography-mass spectrometry/selected-ion monitoring (HPLC-MS/SIM) assay. The concentrations of ketamine and xylazine, diluted in physiological saline, did not change over time at room temperature or at 4°C. However, acepromazine concentrations decreased over time when stored at room temperature. In contrast, undiluted ketamine-xylazine preparations gradually decreased in concentration when stored at room temperature. All of the drug concentrations remained above 90% of their original concentration when stored at 4°C. In conclusion, when diluted in physiological saline, ketamine-xylazine cocktails can be stored for 3 mo, whereas undiluted cocktails can lose efficacy over 3 mo at room temperature. Storage at 4°C could preserve drug stability.

Cette étude vise à évaluer la stabilité de trois préparations de kétamine et xylazine avec ou sans acépromazine gardées à température pièce, ou à 4°C, pour 1, 2 et 3 mois. Les concentrations des drogues ont été comparées à des solutions fraiches, toutes analysées par HPLC-MS/SIM. Les concentrations de kétamine et xylazine, des solutions diluées dans la saline physiologique, sont restées constantes indépendamment du temps et de la température de conservation, par contre la concentration d'acépromazine a diminué dans les préparations gardées à température pièce. En contraste, les concentrations des préparations pures de kétamine et xylazine conservées à température pièce ont diminué avec le temps. En conclusion, la kétamine et la xylazine en cocktail avec du salin peuvent être utilisés pour une période de 3 mois, par contre, conservées à température pièce, les concentrations diminuent progressivement en préparation pure. La conservation des préparations à 4°C favorise la stabilité des drogues.(Traduit par les auteurs).

The effect of excipients on the stability and phase transition rate of xylazine hydrochloride and zopiclone.

The compatibility of thermodynamically unstable polymorph of two active pharmaceutical compounds (xylazine hydrochloride form X and zopiclone form C) with different excipients was investigated. The effects of the excipient and its amount in the sample on the thermal properties and possible chemical interactions were studied. The most commonly used excipients in the pharmaceutical industry - calcium carbonate, lactose hydrate, cellulose, magnesium stearate hydrate and calcium stearate hydrate were selected for this study. The dependence of the phase transition rate from an unstable to a more stable polymorph on the excipients and their amounts in the initial sample was analysed at 80°C, and the corresponding phase transition rate constants were calculated.

Xylazine intoxication in humans and its importance as an emerging adulterant in abused drugs: A comprehensive review of the literature.

Xylazine is not a controlled substance; it is marketed as a veterinary drug and used as a sedative, analgesic and muscle relaxant. In humans, it could cause central nervous system depression, respiratory depression, bradycardia, hypotension, and even death. There have been publications of 43 cases of xylazine intoxication in humans, in which 21 (49%) were non-fatal scenarios and 22 (51%) resulted in fatalities. Most of the non-fatal cases required medical intervention. Over recent years xylazine has emerged as an adulterant in recreational drugs, such as heroin or speedball (a cocaine and heroin mixture). From the 43 reported cases, 17 (40%) were associated with the use of xylazine as an adulterant of drugs of abuse. Its chronic use is reported to be associated with physical deterioration and skin ulceration. Literature shows some similar pharmacologic effects between xylazine and heroin in humans. These similar pharmacologic effects may create synergistic toxic effects in humans. Therefore, fatalities among drug users may increase due to the use of xylazine as an adulterant. Xylazine alone has proven harmful to humans and even more when it is combined with drugs of abuse. A comprehensive review of the literature of non-fatal and fatal xylazine intoxication cases including those in which the substance was used as adulterant is presented, in order to increase the awareness in the forensic community, law enforcement, and public health agencies.

Investigation of the phase transitions occurring during and after the dehydration of xylazine hydrochloride monohydrate.

This paper reports an investigation of a complex solid state phase transition where two inter-converting polymorphs (X and A) of the pharmaceutical molecule xylazine hydrochloride formed and transformed during and after the dehydration of its monohydrate (H). The crystal structures of all three forms were compared. During the investigation of this solid state phase transition it was determined that the dehydration of H produced either a pure X form, or a mixture of the X and A forms. The phase composition depended on the sample preparation procedure and the experimental conditions. It was found that grinding of the hydrate enhanced the formation of polymorph X as a product of dehydration, whereas higher humidity, temperature, or mechanical compression enhanced the formation of polymorph A. The transition mechanism of this complex process was analysed and explained by taking into account the crystal structures of these three forms.

Liquid chromatography-tandem mass spectrometry detection of the quaternary ammonium compound mebezonium as an active ingredient in t61.

Quaternary ammonium compounds pose an analytical challenge. Mebezonium, a muscle-relaxing agent contained in veterinary euthanasia solution T61, was analyzed in body fluids, organs, and injection sites of a veterinarian by liquid chromatography-tandem mass spectrometry (LC-MS-MS) method. Additionally, embutramide and tetracaine, which are two other active ingredients contained in T61, methadone, xylazine, and analgesics were detected by LC-MS-MS and high-performance liquid chromatography-ultraviolet detection methods. For detection of mebezonium a solid-phase extraction (SPE) combined with ionpairing reagent heptafluorobutyric acid was developed. Separation was achieved on Phenomenex Synergi Hydro RP C(18) column combined with ammonium formate buffer and acetonitrile (pH 3.5). To enrich other drugs, liquid-liquid extraction procedures were used. Most of these drugs were separated on a Restek Allure PFP Propyl column using the mentioned mobile phase. Mebezonium and embutramide were detected in femoral vein serum in concentrations of 10.9 and 2.0 mg/L, respectively. The concentration of xylazine and methadone in serum was 2.0 and 0.4 mg/L, respectively. The LC-MS-MS method with SPE combined with an ion-pairing reagent allowed the quantitation of mebezonium. Methadone was detected in toxic concentrations and was, in combination with xylazine and T61, considered to be the cause of death.

The relative stability of xylazine hydrochloride polymorphous forms.

All four known xylazine hydrochloride polymorphous forms were obtained and their relative stabilities were compared directly at three different temperatures. At higher temperatures, it is possible to determine the relative stability of all forms directly by measuring the changes in the composition of the mixtures of two polymorphous forms using powder x-ray diffraction methods. At lower temperatures, a solvent was added to the mixture and the changes in composition were determined. Polymorph transition temperatures were determined directly. To predict the transition temperature which was not found using the direct method, the polymorph melting data and determined transition temperatures were used. A phase stability diagram was constructed from the acquired data. The stability of all anhydrous polymorphous forms was compared in the presence of water vapor pressure that was higher than the equilibrium pressure.

Hydration and dehydration kinetics of xylazine hydrochloride.

From the experiments where mixture of xylazine hydrochloride hydrate H and anhydrous X were held at constant conditions, the stable form of xylazine hydrochloride can be found out. To determine equilibrium relative humidity, the unstable form of xylazine hydrochloride was inserted in thermostated humidity chamber and its weight was recorded by weighing the sample outside the chamber. The kinetic model and the rate constant for each condition were determined. The rate constants give information regarding the speed of the process at every experimentally used relative humidity. Thus using the data in coordinates k-p for each temperature it is possible to determine the water vapor pressure of the equilibrium. With this method the phase boundary for xylazine hydrochloride was determined and hydration enthalpy was calculated. The hydration rates of xylazine polymorphs A and X were investigated.

Solid-phase extraction and gas chromatographic- mass spectrometric determination of the veterinary drug xylazine in human blood.

This paper presents a method for the determination of xylazine in whole blood using solid-phase extraction and gas chromatography-mass spectrometry. This technique required only 0.5 mL of sample, and protriptyline was used as internal standard (IS). Limits of detection and quantitation (LOQ) were 2 and 10 ng/mL, respectively. The method was found to be linear between the LOQ and 3.50 microg/mL, with correlation coefficients higher than 0.9922. Precision (intra- and interday) and accuracy were in conformity with the criteria normally accepted in bioanalytical method validation. The analyte was stable in the matrix for at least 18 h at room temperature and for at least three freeze/thaw cycles. Mean recovery, calculated at three concentration levels, was 87%. To the best of our knowledge, this is the first time that solid-phase extraction is used as sample preparation technique for the determination of this compound in biological media. Because of its simplicity and speed when compared to other extraction techniques, the herein described method can be successfully applied in the diagnosis of intoxications by xylazine.

Refractometry for quality control of anesthetic drug mixtures.

Injectable anesthetic drugs used in rodents are often mixed and further diluted to increase the convenience and accuracy of dosing. We evaluated clinical refractometry as a simple and rapid method of quality control and mixing error detection of rodent anesthetic or analgesic mixtures. Dilutions of ketamine, xylazine, acepromazine, and buprenorphine were prepared with reagent-grade water to produce at least 4 concentration levels. The refraction of each concentration then was measured with a clinical refractometer and plotted against the percentage of stock concentration. The resulting graphs were linear and could be used to determine the concentration of single-drug dilutions or to predict the refraction of drug mixtures. We conclude that refractometry can be used to assess the concentration of dilutions of single drugs and can verify the mixing accuracy of drug combinations when the components of the mixture are known and fall within the detection range of the instrument.

A reported case involving impaired driving following self-administration of xylazine.

A case of suspected drug-impaired driving involving self-administration of xylazine (Xyla-Ject), a veterinary tranquilizing agent, and paroxetine is presented. Qualitative and quantitative analysis of xylazine and paroxetine were performed by gas chromatography with a flame-ionization detector (GC-FID) and gas chromatography/mass spectrometry (GC/MS). Whole blood xylazine and paroxetine concentrations were 0.57 and 0.02 microg/ml, respectively.

Multi-residue analysis of tranquillizers in meat: confirmatory assays using mass spectrometry.

A rapid and sensitive multi-residue method was developed to attempt to confirm the presence of the beta-blocker carazolol and the tranquillizers acepromazine, azaperone, chlorpromazine, propionylpromazine and xylazine in pig muscle tissues. The procedure involves determination by liquid chromatography coupled with tandem mass spectrometry. The liquid chromatographic separation was performed on a Symmetry C18 column with gradient elution. A mixture of aqueous buffer, containing 0.01% m/v trifluoroacetic acid (pH 3.5), and acetonitrile at a flow rate of 0.4 ml min-1 was used as the mobile phase. The abundant parent ions [M+ H+] produced by positive electrospray ionisation were selected for collisional dissociation with argon. Fragment ions were recorded with daughter ion scan and multiple reaction monitoring. The analytes were identified unambiguously by assessing retention times and diagnostic ions in meat samples spiked from 50 micrograms kg-1 [maximum residue limit (MRL) for azaperone and azaperol] to 5 micrograms kg-1 (MRL for carazolol).