Evaluation of the stability and stratification of propofol and ketamine mixtures for pediatric anesthesia.

BACKGROUND: The combination of propofol and ketamine is commonly used for total intravenous anesthesia. These drugs can be delivered in different syringes or in the same syringe. We hypothesized that the drugs might separate and different concentrations of each drug could be found in different parts of the syringe during the procedure period when they were mixed in 1 syringe. METHODS: Twelve 60-mL polypropylene syringes were prepared by mixing propofol and ketamine as 4 groups on the basis of propofol/ketamine mixture ratios (5:1 and 6.7:1) and propofol solution concentrations. Syringes were placed upright in the vertical position into a rack and kept at room temperature (21.5-22.5°C), in daylight conditions and were not moved for 360 minutes. Samples of the mixture were taken from both the top and the bottom of the syringe. The first 1 mL of the samples was discarded, the following second 1 mL of the samples was filtered using 0.2-µm polytetrafluoroethylene filters and measured twice (n = 6). Samples were taken at the following time intervals: T0, T10, T30, T60, T90, T120, T180, T240, T300, and T360 min. Syringes were checked visually for any color change and separation lines between the drugs. RESULTS: There were no significant differences between the propofol and ketamine concentrations of the top and bottom samples in all 4 groups. In addition, there were no statistically significant changes of propofol and ketamine concentrations of samples over 360 minutes in any of the 4 groups. No visual changes were observed during 6 hours' observation. CONCLUSION: The results of our measurements demonstrated that mixtures of propofol (1% and 2%) and ketamine at 5:1 and 6.7:1 ratios could be used in terms of mixture homogeneity and stability in a polypropylene syringe during a 6-hour period at room temperature.

Long-term stability of ketamine hydrochloride 50mg/ml injection in 3ml syringes.

INTRODUCTION: Ketamine hydrochloride (Ketalar(®)) injection is often used as a general anesthetic agent. It is particularly suited to short-term interventions. It can also be used as an inducer of anesthesia before the administration of other anesthetic agents. The aim of this study was to evaluate the stability of ketamine hydrochloride in 3ml polypropylene syringes after storage for up to 180days at room temperature. METHOD: Syringes containing ketamine hydrochloride (50mg/ml) were prepared and stored at room temperature (25°C) for 180days. The concentrations were measured by validated ultra-performance liquid chromatography-diode array detection at 0, 7, 14, 28, 60, 84, 112, 140 and 180days. A degradation test was performed to evaluate the specificity of the analysis. At each time point, the pH, color and visible particles of each solution were also assessed. RESULTS: Degradation tests proved no interfering peaks with ketamine. All solutions were physically stable during the storage. The lower confidence limit of the concentration for these solutions remains superior to 90% of the initial concentration at this date as recommended by the Food and Drug Administration (FDA) until 180days (100%±2%). CONCLUSION: Solutions of ketamine (50mg/ml) were chemically stable for 180days in polypropylene syringes with storage at room temperature and could be prepared in advance by a centralized intravenous admixture service.

Rapid detection of ketamine and norketamine in rat hair using micropulverized extraction and ultra-performance liquid chromatography-electrospray ionization mass spectrometry.

A new method for the rapid and simultaneous detection of ketamine and its major metabolite, norketamine, in rat hair has been developed by combining micropulverized extraction and ultraperformance liquid chromatography-electrospray ionization mass spectrometry. By using reversed-phase UPLC, ketamine and norketamine were well separated within 2 min. Using ketamine-dosed rat hair, the conditions for micropulverized extraction were optimized, and the limits of detection and quantification of the developed method were found to be 1.7 and 5.7 pg/mg hair for ketamine, respectively. The precisions achieved with this method were slightly better than that obtained with conventional acidic methanol extraction method. Using this proposed method, analysis of the washed rat hair could be completed within 16-17 min. This method is expected to be applied for the analysis of the hair samples of not only rats but also ketamine abusers.

A validated GC-MS method for ketamine and norketamine in hair and its use in authentic cases.

This work has shown that it is a valid method for determining ketamine, norketamine and amphetamines derivates in hair samples of forensic cases. This method was validated meeting the criteria of sensitivity and accuracy for detecting repeated consumption of ketamine in hair samples of forensic interest, according to the proposed cut-off for ketamine of 0.5 ng/mg. The detection of norketamine allowed discriminating between active uses and external contamination. The assessed method was applied for analyzing 1189 hair samples of judicial interest received in the INTCF along 15 months, obtaining 62 positive in ketamine consumption. This means a 5.2% of positivity. Ketamine consumers present a profile of young age (21-30 years old), polydrug use with consumption of synthetic substances preferably MDMA and, then, amphetamine. As consumer is collective, prone to consume new psychoactive substances, requires special attention due to they show a consumer profile with higher prevalence in MDMA than amphetamine, indicating that ketamine consumers belong to a subgroup with a different profile within the INTCF casuistry. The results of the exercises of the proficiency tests performed satisfactorily in all cases. In conclusion, it is a suitable method also to evaluate the chronic consumption of ketamine, in addition to amphetamines in the same method of analysis.

Performance characteristics of ELISAs for monitoring ketamine exposure.

BACKGROUND: Growing misuse of ketamine necessitates the development of high throughput testing approaches. Two commercial enzyme-linked immunosorbent assays (ELISA) for ketamine have recently become available and were adapted for this development. METHOD: The newly available ketamine ELISA reagents were examined to better understand their cross-reacting, calibration and other performance characteristics. ELISA apparent analyte concentrations were also correlated against ketamine concentrations as determined by GC-MS to examine the relationship between these 2 parameters. RESULT: Both adapting ketamine as the targeted analyte, reagent from International Diagnostic Systems (IDS) also responded very significantly to the metabolites of ketamine (norketamine and dehydronorketamine), while the NEOGEN reagent responded very specifically to ketamine. CONCLUSION: NEOGEN ELISA test data exhibit better correlation with the ketamine concentration as determined by GC-MS. It can be more reliably used as the preliminary test method in the 2-step approach now routinely adapted in workplace drug testing programs. Using 100 ng/ml ketamine as the GC-MS cutoff, the corresponding ELISA cutoff value is approximately 110-120 ng/ml. With significantly higher responses to ketamine metabolites, IDS reagent can detect specimens with much lower ketamine/metabolites concentrations and can better meet other testing requirements.

Point of care with micro fluidic paper based device integrated with nano zeolite-graphene oxide nanoflakes for electrochemical sensing of ketamine.

The present study was aimed to develop an ultrasensitive technique for electroanalysis of ketamine; a date rape drug. It involved the fabrication of nano-hybrid based electrochemical micro fluidic paper-based analytical device (EµPADs) for electrochemical sensing of ketamine. A paper chip was developed using zeolites nanoflakes and graphene-oxide nanocrystals (Zeo-GO). EµPAD offers many advantages such as facile approach, economical and potential for commercialization. Nanocrystal modified EµPAD showed wide linear range 0.001-5nM/mL and a very low detection limit of 0.001nM/mL. The developed sensor was tested in real time samples like alcoholic and non-alcoholic drinks and found good correlation (99%). The hyphenation of EµPAD integrated with nanocrystalline Zeo-GO for detection of ketamine has immense prospective for field-testing platforms. An extensive development could be made for industrial translation of this fabricated device.

Hair analysis for ketamine and its metabolites.

A rapid and sensitive method was developed for the simultaneous identification and quantitation of ketamine (K) and its major metabolite, norketamine (NK) in hair. After decontamination, the hair sample was incubated and extracted, and analyzed by gas chromatography-mass spectrometry (GC-MS). Limits of quantitation were found to be 0.05 ng/mg. Hair segments in black color were collected from 15 K abusers. Based on an experiment with 15 cavies with black, white, and brown hair, the mechanism of incorporation of K into hair was investigated. After shaving hair on the back of the cavies (8 cm x 4 cm), they were separated into three groups and administered intraperitoneally once a day for 7 successive days with high, medium, and low doses of K, respectively. Two days after this, hair segments with different colors were shaved. There was a direct correlation between the concentration of K in cavy hair and the dose and DHNK was detected only in high dosage group. The concentration of K increased in the order of white, brown, and black hair. The possible factors responsible for the incorporation of K and its metabolites in hair were discussed.

Illegal use patterns, side effects, and analytical methods of ketamine.

In Asian countries, such as China, Taiwan, and Hong Kong, ketamine (KT) is one of the most prevalent illicit use drugs. KT is regulated by various drug-related laws in many countries, such as Korea, Taiwan, China, U.S.A, Netherlands, UK, Australia, Mexico, and Canada. This review research explored pharmacology and side effects of KT, the illicit use patterns of KT, the analytical methods of KT in biological samples, and the concentrations of KT from abusers and non-abusers. Many side effects of KT have been reported mental and physical problems. Although many studies conducted various analytical methods for KT, this research focused on the urine and hair analysis and compared some parameters of samples, instruments, columns, extraction methods, internal standards, LOD/LOQ levels, metabolites, NK/K ratio, cut off values, and m/z values. Our research also compared the concentrations of KT in biological samples from abusers and non-abusers. Many rapid and precise analytical methods for illegal KT use are needed to be developed and applied to real samples. To minimize and prevent harm from KT, the authorities and appropriate agencies require a careful assessment, evaluation, early identification, and surveillance of KT users in both clinical and social settings. In addition, there is a need to construct a stricter legislative management and provide preventive education to younger individuals because illegal KT use is relatively common among the young populations.

[Determination of ketamine and its metabolites in biological samples].

The abuse of ketamine has gained popularity in recent years. It is important to develop rapid and accurate methods to determine ketamine and its metabolites in biological samples. The metabolites of ketamine are norketamine and dehydronorketamine in vivo. At present, there are blood, urine, hair and so on as specimens for detection, while the methods include GC, GC/MS, HPLC, LC/MS, HPCE etc. In this paper, these methods used for ketamine and its metabolites were reviewed in order to provide some preference for the study in relative fields.

Cut-off proposal for the detection of ketamine in hair.

Ketamine is a powerful anesthetic drug used in both human and veterinary surgery, but it is also commonly misused because of its psychotropic properties. Since the abuse of this drug has been reported in many countries worldwide, its determination in hair samples is offered as a specialist test by hundreds of laboratories. However, unlike other common drugs of abuse, a cut-off level for ketamine in hair has not been fixed yet. Therefore, aim of this study is to propose a concentration value for ketamine in hair analysis, in order to discriminate between chronic and occasional use, and between active use and external contamination. After considering the chemical properties of this molecule, and the experimental data collected in our laboratory or reported in several other published studies, we propose a cut-off level of 0.5ng/mg, as indicative of repeated exposure to ketamine. Additionally, we suggest that the detection of the metabolite norketamine should be mandatory to prove active intake and exclude false positive result from external contamination. Thus, a reasonable cut-off value for norketamine could be fixed at 0.1ng/mg, while the minimal concentration ratio norketamine/ketamine may be positively established at 0.05.

Pharmacokinetics and tissue residues of Telazol in free-ranging polar bears.

A pharmacokinetic and tissue residue study was conducted to assess the risks associated with human consumption of polar bears in arctic Canada that have been exposed to the immobilizing drug Telazol, a mixture of tiletamine hydrochloride and zolazepam hydrochloride. Twenty-two bears were remotely injected with about 10 mg/kg of Telazol. Following immobilization, serum samples were collected serially at regular intervals until the bears awakened. Sixteen of the bears were relocated and killed under permit by local hunters at various times from 0.5 to 11 days after dosing. Serum, kidney, muscle and adipose tissue samples were collected immediately after death. All samples were stored at -70 C until analysis by HPLC. The concentration-time data of tiletamine and zolazepam in serum during the immobilization period were fitted to curves by computer and the pharmacokinetic parameters assessed. In addition, the serum and tissue samples collected at the time of death were analyzed for both parent drugs, for one metabolite of tiletamine (CI-398), and for three metabolites of zolazepam (metabolites 1, 2 and 4). A one-compartment model with first-order absorption and elimination best fit the time-series data for the drugs in serum during the immobilization period. This model gave half-lives (mean +/- SE) for tiletamine and zolazepam of 1.8+/-0.2 h and 1.2+/-0.08 h, respectively, clearance values of 2.1+/-0.3 l x h(-1) x kg(-1) and 1.1+/-0.1 l x h(-1) x kg(-1), and volumes of distribution of 5.2+/-0.6 l/kg and 1.8+/-0.2 l/kg. The concentrations of both drugs and their metabolites declined rapidly to trace levels by 24 h post-dosing, although extremely low concentrations of some metabolites were encountered sporadically over the entire sampling period. In particular, zolazepam metabolite 2, remained detectable in fat and muscle tissue at the end of the study, 11 days after dosing. It was concluded that during immobilization, both tiletamine and zolazepam levels decline rapidly in a monoexponential fashion, and their pharmacokinetic parameters in polar bears are similar to those observed in other species. Tissue levels of the drugs and their metabolites declined sufficiently rapidly that individuals eating meat from exposed bears would be unlikely to experience pharmacological effects from the drugs. Nevertheless, slight exposure to the drugs and/or their metabolites might be possible for an indeterminate time after dosing.

[Preparation of ketamine tablets for treatment of patients with neuropathic pain].

Ketamine is known to have distinguished analgesic effects without anesthetic when administered in a low dose. Since ketamine is not commercially available except injection forms, we prepared ketamine tablets for the home-care medication of patients with neuropathic pain. The direct compression or wet granulation method was employed to form 150 mg of tablets containing 50 mg of ketamine. The latter method was superior to the former one in terms of content uniformity, weight variation and disintegration tests of the tablets. Ketamine contents in the tablet prepared by the wet granulation method were unchanged for 12 weeks under the conditions of 25 degrees C and 75% relative humidity (RH). The Cmax and AUC0-3 h values for ketamine after administration of the tablet were slightly smaller than those of the syrup in a healthy volunteer. However, analgesic effects of the tablet was similar to that of the syrup in a patient with neuropathic pain. And the tablet was also effective for another four patients with neuropathic pain. These results indicate that ketamine tablets are useful for the home-care medication of patients with neuropathic pain.

Determination of ketamine and norketamine in hair by micropulverized extraction and liquid chromatography-high resolution mass spectrometry.

Ketamine (KT), primarily used as a general anaesthetic agent in clinical practice, has become very popular in recent years as a recreational drug, due to its dissociative and hallucinogenic effects. A liquid chromatography-high resolution mass spectrometry (LC-HRMS) method has been developed and validated for the quantification of KT and its main metabolite norketamine (NK) in 2.0mg of hair. Sample preparation consisted of a rapid, simultaneous pulverization and extraction step in acidic solution, followed by centrifugation and filtration. Gradient elution was performed by an Atlantis T3 analytical column, and deuterated KT was used as the internal standard. Positive ion electrospray ionization and HRMS determination in full-scan mode were achieved with an Orbitrap mass spectrometer. The method has a linear range of 0.05-50 ng/mg, a limit of quantisation of 0.05 ng/mg and a limit of detection of 0.02 ng/mg for both KT and NK. The validated method was applied for the determination of KT and NK in two authentic hair samples from subjects suspected of taking psychoactive substances. The detection of the metabolite at low concentration gave proof for systemic drug origin and an investigation into the possible presence of further metabolites was performed by means of retrospective screening.

The first international proficiency test on ketamine and norketamine in hair.

This paper discusses the organization of the first international proficiency test (PT) programme on ketamine (K) and norketamine (NK) in hair samples. The primary objective of the programme was to evaluate the analytical capability of participating laboratories on hair analysis for K and NK via comparison of results. Authentic samples, instead of spiked samples were used in the programme to mimic the analysis of incorporated illicit drugs in real-life situations. Eight of the ten participating medical or forensic laboratories from Australia, France, Hong Kong, Italy, Singapore and the USA returned results to the organizer. Quantification methods from these laboratories were confined to GC-MS and LC-MS/MS. Performance assessment based on z-score indicated that only three laboratories achieved satisfactory results for both the analysis of K and NK. It was concluded that the overall performance of the participating laboratories was fair and there is still room for further improvement. Additional similarly designed PT programmes are recommended to be organized in order to encourage reliable measurements of illicit drugs in hair samples. Taking into account the substantial effect on the consensus values within limited number of data points, a recommendation on the provision of reference values assigned by accurate methods will be of benefit to small size PT programmes in the forensic field.

Micro-solid phase extraction coupled with high-performance liquid chromatography-tandem mass spectrometry for the determination of stimulants, hallucinogens, ketamine and phencyclidine in oral fluids.

A confirmatory method for the determination of illicit drugs based on micro-solid phase extraction with modified tips, made of a functionalized fiberglass with apolar chains of octadecylsilane into monolithic structure, has been developed in this study. Drugs belonging to different chemical classes, such as amphetamine, methamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethylamphetamine, cocaine, benzoylecgonine, ketamine, mescaline, phencyclidine and psilocybine were analyzed. The quantitation was performed by liquid chromatography-tandem mass spectrometry and the analytes were detected in positive ionization by means of an electrospray source. The limits of quantification ranged between 0.3 ng mL(-1) for cocaine and 4.9 ng mL(-1) for psilocybine, with coefficients of determination (r(2)) >0.99 for all the analytes as recommended in the guidelines of Society of Forensic Toxicologists-American Association Forensic Sciences.

Roadside detection of impairment under the influence of ketamine--evaluation of ketamine impairment symptoms with reference to its concentration in oral fluid and urine.

Although there are many roadside testing devices available for the screening of abused drugs, none of them can be used for the detection of ketamine, a popular abused drug in Hong Kong. In connection to local drug driving legislation, effective roadside detection of ketamine in suspected drug-impaired drivers has to be established. According to the drug evaluation and classification program (DEC), ketamine is classified in the phencyclidine (PCP) category. However, no study has been performed regarding the signs and symptoms exhibited by users under the influence of ketamine. In a study to develop a protocol for effective roadside detection of drug-impaired drivers, 62 volunteers exiting from discos were assessed using field impairment tests (FIT) that included measurements of three vital signs (i.e. body temperature, pulse rate and blood pressure), three eye examinations [pupil size, lack of convergence (LOC) and horizontal gaze nystagmus (HGN)] and four divided attention tests (Romberg, one-leg stand, finger-to-nose and walk-and-turn tests). Subsequent laboratory analysis of oral fluid and urine samples from the participants revealed the presence of common abused drugs in both the urine and oral fluid samples of 55 subjects. The remaining 7 subjects with no drug in their oral fluid samples were used as drug-free subjects. In addition, 10 volunteers from the laboratory who were regarded as drug-free subjects were also assessed using the same FIT. Among the 62 volunteers, 39 of them were detected with ketamine in their oral fluid. Of these ketamine users, 21 of them (54%) with only ketamine found in their oral fluid samples while the rest (18 subjects) of them had other drugs (i.e. MA, MDMA, benzodiazepines and/or THC) in addition to ketamine. Of the 21 ketamine-only users, 15 of them (71%) were successfully identified by FIT. It was found that when salivary ketamine concentrations were greater than 300 ng/mL, signs of impairment became evident, with over 90% detection rate using the FIT. By comparing the FIT observations on the 21 ketamine-only users with the drug-free subjects, the typical signs and symptoms observable for subjects under the influence of ketamine included LOC, HGN, elevated pulse rate and in general, failing the divided attention tests, especially the walk-and-turn and one-leg stand.

Clorhidrato de ketamina: técnicas analíticas necesarias para el desarrollo tecnológico / Ketamine hydrochloride: analytical techniques needed for technological development

El desarrollo tecnológico requiere de métodos analíticos confiables que permitan la cuantificación del fármaco en diferentes etapas de la investigación. El objetivo de este trabajo fue las validaciones prospectivas de 2 métodos analíticos, uno por UV-VIS y otro por cromatografía líquida de alta eficiencia, desarrolladas para el control del proceso de fabricación, de la calidad y para el estudio de estabilidad de ketamina. A las técnicas se le determinaron los parámetros de desempeño, especificidad, linealidad, exactitud, rango y precisión. Los resultados alcanzados permiten concluir que ambos métodos cumplen con los requisitos establecidos como aceptables para cada uno de los casos en el rango de concentraciones establecido. El método espectrofotométrico puede utilizarse en el control del proceso de producción y el control de calidad del producto terminado al igual que el método cromatográfico; el primero, es de elección para el control de proceso de fabricación por su sencillez y rapidez, y el segundo, para el estudio de estabilidad del producto por su elevada especificidad.

Technological development requires of reliable and analytical methods to quantify drugs in different stages of research. Aim of present paper was the prospective validations of two analytical methods, one by UV-VIS, and the other by high performance liquid chromatography, developed to control of manufacture process, quality, and to study of Ketamine stability. Techniques included the following parameters: performance, specificity, linearity, accuracy, rank, and precision. Results achieved allow concluding that both methods fulfill the criteria established as fair to each of the cases in rank of concentrations stetted. Spectrophotometry method may be used in control of production process and in control of quality of end product just like the chromatography method, the first one, is the choice to control of manufacture process due to its simplicity and speed, and the second one, to study of product stability due to its high specificity.