Oxidation of amine-based pharmaceuticals with unactivated peroxymonosulfate: Kinetics, mechanisms, and elimination efficiency of NDMA formation.

Amine-based pharmaceuticals are a significant class of N-nitrosodimethylamine (NDMA) precursors. This study investigated the use of unactivated peroxymonosulfate (PMS) to control amine-based pharmaceuticals and their NDMA formation potential. Kinetic analysis and product identification revealed that sumatriptan and doxylamine primarily underwent reactions at their tertiary amine group, while ranitidine and nizatidine had both tertiary amine and thioether group as reaction sites. The NDMA formation from sumatriptan and doxylamine during post-chloramination was significantly reduced with the abatement of the parent contaminants, while the formation of NDMA remained high even if full abatement of ranitidine and nizatidine was achieved. Product formation kinetics and reference standard tests revealed the great contribution of transformation products to NDMA formation. Ranitidine could be oxidized to sulfoxide-type product ranitidine-SO and N-oxide type product ranitidine-NO. Ranitidine-SO exhibited a high NDMA yield comparable to that of ranitidine (>90%), while ranitidine-NO showed a low NDMA yield (2%). With further oxidation of ranitidine-SO at the tertiary amine group, NDMA formation was reduced by more than 90%. The underlying mechanism for the importance of the tertiary amine group in NDMA formation was demonstrated by quantum chemical calculation. These findings underscore the potential of PMS pre-oxidation on NDMA control.

Chemometric Quality Assessment of Doxylamine Succinate With Its Degradation Product: Implementation of Two Predictive Models on UV-Spectrophotometric Data of Anti-Emetic Binary Mixture.

BACKGROUND: The combination of pyridoxine hydrochloride (PYR) and doxylamine succinate (DOX) as an antiemetic binary mixture is used to treat nausea and vomiting during pregnancy. OBJECTIVE: Two validated, accurate, and selective chemometric models were developed to assay binary mixture in the presence of DOX oxidative degradation product (DOX DEG) that could be characterized using LC-MS. METHODS: Partial least squares (PLS) regression and principal component regression (PCR) were selected for the determination of our binary mixture in presence of degradation. To exhibit a training set of 25 mixtures that had various percentages of tested substances in five level 3 variables, an experimental design was chosen. A set of 18 synthetic mixtures in the concentration range 10.0-50.0 µg/mL, 12.00-20.0 µg/mL, and 6.0-30.0 µg/mL for PYR, DOX, and DOX DEG, respectively, were used in the construction of the calibration models. Then set of seven synthetic mixtures with different concentrations were used in the construction of the validation models. RESULTS: In validation samples with low root mean square error of prediction (RMSEP), the suggested models successfully predicted the concentrations of our drugs. The models developed were evaluated by RMSEP calculation, and the values obtained were 0.341, 0.196, and 0.388 for PYR, DOX, and DOX DEG, respectively, using PLS. While using PCR, RMSEP calculation and the values obtained were 0.400, 0.256, and 0.375 for PYR, DOX, and DOX DEG, respectively. The developed models were validated according to ICH strategies. CONCLUSIONS: The corresponding methods are suitable to determine PYR and DOX in pure form, pharmaceutical dosage form, and in the presence of DOX DEG product. HIGHLIGHTS: The study of drug breakdown pathways is very important nowadays, so even in the presence of degradation and extreme spectral overlapping, the suggested PLS and PCR spectrophotometric approaches were able to identify PYR and DOX.

Application of a molecular networking approach for clinical and forensic toxicology exemplified in three cases involving 3-MeO-PCP, doxylamine, and chlormequat.

Untargeted toxicological screening is an analytical challenge, given the high number of molecules and metabolites to be detected and the constant appearance of new psychoactive substances (NPS). The combination of liquid chromatography with high-resolution tandem mass spectrometry (HRMS/MS) in a data-dependent acquisition mode generates a large volume of high quality spectral data. Commercial software for processing MS data acquired during untargeted screening experiments usually compare measured features (mass, retention time, and fragmentation spectra) against a predefined list of analytes. However, there is a lack of tools for visualizing and organizing MS data of unknown compounds. Here, we applied molecular networking to untargeted toxicological screening. This bioinformatic tool allows the exploration and organization of MS/MS data without prior knowledge of the sample's chemical composition. The organization of spectral data is based on spectral similarity. Hence, important information can be obtained even before the annotation step. The link established between molecules enables the propagation of structural information. We applied this approach to three clinical and forensic cases with various matrices: (a) blood and a syringe content in a forensic case of death by self-injection, (b) hair segments in a case of drug-facilitated assault, and (c) urine and blood samples in a case of 3-methoxyphencyclidine intoxication. Data preprocessing with MZmine allows sample-to-sample comparison and generation of multisample molecular networks. Our present study shows that molecular networking can be a useful complement to conventional approaches for untargeted screening interpretation, for example for xenobiotics identification or NPS metabolism elucidation.

Development and validation of a generic high-performance liquid chromatography for the simultaneous separation and determination of six cough ingredients: Robustness study on core-shell particles.

A generally applicable high-performance liquid chromatographic method for the qualitative and quantitative determination of pharmaceutical preparations containing phenylephrine hydrochloride, paracetamol, ephedrine hydrochloride, guaifenesin, doxylamine succinate, and dextromethorphan hydrobromide is developed. Optimization of chromatographic conditions was performed for the gradient elution using different buffer pH values, flow rates and two C18 stationary phases. The method was developed using a Kinetex® C18 column as a core-shell stationary phase with a gradient profile using buffer pH 5.0 and acetonitrile at 2.0 mL/min flow rate. Detection was carried out at 220 nm and linear calibrations were obtained for all components within the studied ranges. The method was fully validated in agreement with ICH guidelines. The proposed method is specific, accurate and precise (RSD% < 3%). Limits of detection are lower than 2.0 µg/mL. Qualitative and quantitative responses were evaluated using experimental design to assist the method robustness. The method was proved to be highly robust against 10% change in buffer pH and flow rate (RSD% < 10%), however, the flow rate may significantly influence the quantitative responses of phenylephrine, paracetamol, and doxylamine (RSD% > 10%). Satisfactory results were obtained for commercial combinations analyses. Statistical comparison between the proposed chromatographic and official methods revealed no significant difference.

Post-mortem evidence of doxylamine in toxicological analyses.

BACKGROUND: Doxylamine (DA) is widely available in pharmacies without prescription and can be used in suicidal intention because of its sedative and anticholinergic properties. Research of literature shows that only a few publications deal with post-mortem evidence of DA and its interpretation during toxicological examination. MATERIAL AND METHODS: In this study, all cases with a positive detection of DA during toxicological analyses with high-performance liquid chromatography in the time period 2000 to 2010 at the Institute of Legal Medicine and Forensic Sciences in Berlin, Germany were retrospectively analysed and interpreted, taking into account police investigations, autopsy results and toxicological analyses. RESULTS: In total, 22 cases with DA intoxications were discovered (♂=16/♀=6, age-at-death range 17 to 90years). Maximum blood concentration was measured at 77.5µg/mL. Cause of death was due to DA intoxication in eight suicide cases; seven of those were combined intoxications (DA and other substances, particularly diphenhydramine). During the evaluated time period no monointoxications with DA were discovered. CONCLUSION: Benchmarks published in past literature are meant as orientation during evaluation of post-mortem DA evidence. These should not be used as absolute values and need to be interpreted individually in each case. Post-mortem redistribution needs to be considered as a main factor in alteration of DA concentration measurement. Furthermore, proof of DA ingestion found in gastric content should only be interpreted quantitatively due to unreliable calculation of the ingested amount. In conclusion, a variety of factors, such as the time period between time of death and the time of the first toxicological analysis, the condition of the body and the findings at autopsy, must also be critically considered.

A tendency for re-offending in drug-facilitated crime.

The authors present 3 cases that demonstrate a return to DFC following periods of inactivity. The offences occurred in Paris and its suburbs and in each of the cases there were two distinct periods of activity by the offenders with 2, 8 and 22 victims attributed to each of the perpetrators. To 20mg of decontaminated and cut hair, 100 pg/mg of clonazepam-d4 was added as internal standard. Hair specimens were extracted with CH(2)Cl(2)/ether after incubation overnight at 56 degrees C in pH 7.6 buffer. Extractions were performed on blood and urine using Toxi-tube A with 5 ng/mL of clonazepam-d4. The residues were analyzed by LC-ESI-MS/MS. Calibration curves in blood and urine (0.5-500 ng/mL) were prepared by spiking aliquots of blank fluids (r(2)>0.9816 for all drugs). LOD in body fluids ranged 0.5-10 ng/mL. Calibration curves in hair (0.5-100 pg/mg) were prepared by spiking aliquots of blank hair (r(2)>0.9877 for all drugs). LOD in hair ranged 0.5-5 pg/mg. Case #1: Two young women were raped with an interval of approximately 1 year between the incidents. Lorazepam (present, <2 pg/mg) was detected in hair obtained from the first victim, and zolpidem (19 pg/mg) in hair of the second one. The offender was in jail between the two offences. Case #2: The offender approached a total of 8 men and women who were aged over 50 years. The offender was in jail between the two series of respectively 3 and 5 victims. Zopiclone was detected in victims' hair (n=7) at concentrations 13-42 pg/mg. Case #3: The offender stole thousands of Euros using credit cards obtained from 22 different wealthy victims. He employed a cocktail of up to 6 drugs made up of: flunitrazepam, clonazepam, doxylamine, cyamemazine, zolpidem and lorazepam. Drugs were detected in all victims' hair (n=18) at concentrations in the range 1-81 pg/mg for all drugs. Between the two series (of respectively 4 and 16 victims) the offender spent 6 months in jail, and then police spent 6 months looking for him while he was under judiciary control prior to his judgment. Segmental hair analysis permits retrospective information on drug exposure and should be considered in the investigation of drug-facilitated crimes not only to prove single exposure but also when there has been any appreciable delay in samples being obtained for analysis. Indeed, in 56% cases reported in this paper, due to the long time that elapsed between offences and the opportunity to obtain samples for analysis hair analysis was considered the only viable matrix to investigate the possibility of drug involvement in the crimes. Our experience demonstrates that the incidence of re-offending in DFC after a period of inactivity (often due to imprisonment) may be of concern, notably in big cities.

The identification of ingested dandelion juice in gastric contents of a deceased person by direct sequencing and GC-MS methods.

DNA and chemical analysis of gastric contents of a deceased person were handled in this work. The body of the victim was discovered in his car, submerged in a lake. We were asked to determine whether or not the gastric contents of the victim harbored drugs and dandelion material. It was suspected that the victim had been murdered by poisoning with an excess amount of sleeping medication (doxylamine), which had been homogenized with dandelion. The concentrations of 11.4 and 27.5 mg/kg of doxylamine detected from spleen and liver of the victim were far higher than the assumed therapeutic concentration. Via gas chromatography-mass spectrometry (GC-MS) analysis and direct sequencing analysis of plant genetic markers such as intergenic transcribed spacer, 18S ribosomal RNA (rRNA), rbcL and trnLF, it was confirmed that the gastric contents of the victim contained taraxasterol, which is one of the marker compounds for dandelion and contained dandelion species-specific rbcL and trnL-trnF IGS (trnLF) sequences. The initial PCR of the genomic DNA isolated from the gastric contents showed insufficient quantity, and the second PCR, of which the template was a portion of the initial PCR products, exhibited a sufficient quantity for direct sequencing. rbcL and trnLF located in the cpDNA resulted in the successful determination of dandelion DNA in a decedent's stomach contents. GC-MS identifies the actual presence of a taraxasterol at 28.4 min. Raw dandelion was assumed to be used as a masking vehicle for excess sleeping drug (doxylamine).

Simultaneous determination of a ternary mixture of doxylamine succinate, pyridoxine hydrochloride, and folic acid by the ratio spectra-zero-crossing, double divisor-ratio spectra derivative, and column high-performance liquid chromatographic methods.

Three simple, rapid, and accurate methods, i.e., the derivative ratio spectra-zero-crossing method (method I), double divisor-ratio spectra derivative method (method II), and column reversed-phase high-performance liquid chromatographic (RP-HPLC) method (method III) were developed for the simultaneous determination of doxylamine succinate (DOX), pyridoxine hydrochloride (PYR), and folic acid (FA) in their ternary mixtures and in tablets. In methods I and II, the calibration graphs were linear in the range of 2.5-80, 1.0-40, and 1.0-30 microg/mL for DOX, PYR, and FA, respectively. In the HPLC method, the separation of these compounds was performed using mobile phase consisting of 0.05 M phosphate buffer (pH 6.3)-methanol-acetonitrile (50 + 20 + 30, v/v/v), and UV detection was performed at 263 nm. Linearity was observed between the concentrations of the analytes and peak areas [correlation coefficient (r) > or =0.9998] in the concentration range of 1.0-200, 4.0-600, and 4.0-600 microg/mL for DOX, PYR, and FA, respectively. The standard deviation of retention time in method III was 0.011, 0.015, and 0.016 for DOX, PYR, and FA, respectively. The precision studies for all of the methods gave relative standard deviation values of <2%. The results obtained from the methods were statistically compared by means of Student's t-test and the variance ratio F-test. It was concluded that all of the developed methods were equally accurate, sensitive, and precise. These methods could be applied to determine DOX, PYR, and FA in their combined dosage forms.

An estimate of the proportion of drug-facilitation of sexual assault in four U.S. localities.

In recent years, drugs including flunitrazepam, gamma-hydroxybutyrate, ketamine, and ethanol, have become popularly associated with drug-facilitated sexual assault. Other drugs are also candidates as factors in "drug facilitated sexual assault" (DFSA). The true extent of DFSA is not known, and is difficult to estimate. We recruited sexual assault complainants at four clinics in different parts of the U.S. to anonymously provide urine and hair specimens, and to answer questions about suspected drugging, drug use, and the sexual assault incident. Urine and hair specimens were tested for 45 drugs, including ethanol, and those pharmacologically capable of inducing sedation, amnesia, or impairment of judgment. Analytical test results were used to estimate the proportion of subjects, and the proportion of all complainants to the clinic in the same time period, who were victims of DFSA. Overall, cases of 43% of 144 subjects, and 7% of 859 complainants, were characterized as DFSA. Subjects underreported their use of drugs. The role of toxicological results and history in characterizing DFSA cases is discussed.

[Chemicotoxicological evaluation of doxylamine].

The conditions of doxilamine isolation from biological fluids are studied. The method of its extraction with a mixture of organic solvents in pH 9 is proposed. Identification of doxilamine with techniques of thin layer chromatography, UV-, IR-spectroscopy, chromato-mass-spectrometry, densitometry, gas-liquid chromatography is described. UV-spectrometry, gas chromatography and densitometry can be used for quantitation of doxilamine.

Possible role of pseudoephedrine and other over-the-counter cold medications in the deaths of very young children.

The Philadelphia Medical Examiners Office has reported a series of 15 deaths between February 1999 and June 2005 of infants and toddlers 16 months and younger in which drugs commonly found in over-the-counter (OTC) cold medications were present. A total of 10 different drugs were detected: pseudoephedrine, dextromethorphan, acetaminophen, brompheniramine, carbinoxamine, chlorpheniramine, ethanol, doxylamine and the anticonvulsants, phenobarbital, and phenytoin. The drugs were confirmed and quantified by gas chromatography (GC)-mass spectrometry, with the exception of ethanol, which was analyzed by headspace GC and of phenobarbital and phenytoin that were quantified by GC with a nitrogen phosphorus detector. The most predominant drug was pseudoephedrine, which was found in all of the cases (blood concentration, n=14, range=0.10-17.0 mg/L, mean=3.34 mg/L) and was the sole drug detected in three cases. Acetaminophen was detected in blood from each of the five cases with sufficient sample. Other drugs (with frequency of detection) were dextromethorphan (five cases), carbinoxamine (four cases), chlorpheniramine (two cases) and brompheniramine, doxylamine, and ethanol (one case each). In the majority of the cases, toxicity from drugs found in easily available OTC medications was listed either as the direct cause of death or as a contributory factor. The manner of death was determined to be natural in only two of the cases. This postmortem study supports previous evidence that the administration of OTC cold medications to infants may, under some circumstances, be an unsafe practice and in some cases may even be fatal. The treating physicians and the general public need to be made more aware of the dangers of using OTC cold medications to treat very young children so that these types of tragedies might be avoided.

[Detection of reladorm and donormil in forensic-medical examination of cadavers].

A method was suggested for identifying reladorm and donormil in pharmaceutical drugs and biological objects. The above substances are isolated by 96% ethanol or by mixture of chloroform and isopropanol. 7 color reactions, 3 microcrystalloscopic reactions and chromatography in thin sorbent layer are suggested for identification.

Differential protonation and dynamic structure of doxylamine succinate in solution using 1H and 13C NMR.

A protonation and dynamic structural study of doxylamine succinate, a 1:1 salt of succinic acid with dimethyl-[2-(1-phenyl-1-pyridin-2-yl-ethoxy)ethyl]amine, in solution using one- and two-dimensional 1H and 13C NMR experiments at variable temperature and concentration is presented. The two acidic protons of the salt doxylamine succinate are in 'intermediate' exchange at room temperature, as evidenced by the appearance of a broad signal. This signal evolves into two distinct signals below about -30 degrees C. A two-dimensional 1H-1H double quantum filtered correlation experiment carried out at -55 degrees C shows protonation of one of the acidic protons to the dimethylamine nitrogen. A two-dimensional rotating frame 1H-1H NOE experiment at the same temperature reveals that the other proton remains with the succinate moiety. Comparison of the 1H and 13C chemical shifts and the 13C T1 relaxation times of the salt with those of the free base further substantiate the findings.

Suicide through doxylamine poisoning.

Doxylamine is an antihistamine of the ethanolamine class. It is used primarily as a sleep-inducing agent. Only a few reports can be found in the literature about lethal intoxications with doxylamine, but many with combined intoxications. Doxylamine is, aside from diphenhydramine, the only chemically defined active ingredient in some sleeping medications which is available without a prescription in the Federal Republic of Germany. Two cases of doxylamine poisoning are presented, in which high doxylamine concentrations were found in the blood and organs.

Simultaneous determination of pyridoxine hydrochloride and doxylamine succinate from tablets by ion pair reversed-phase high-performance liquid chromatography (RP-HPLC).

A new, simple, precise, and rapid ion pair reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed for the simultaneous determination of pyridoxine hydrochloride (PYR) and doxylamine succinate (DOX) in tablets. The stationary phase was a Microbondapak C18 column (10 mu, 300 mm x 3.9 mm i.d.). The mobile phase was water:methanol (60:40) containing 10 mM heptanesulfonic acid and 0.25% triethylamine and adjusted to pH 2.2 with orthophosphoric acid. Detection was carried out at 263 nm using an ultraviolet (UV) detector. The flow rate was 1.0 ml/min, and retention times were 3.65 min and 7.32 min for PYR and DOX, respectively. The linearity was obtained in the concentration range 0.5-500 micrograms/ml for PYR and DOX. Mean percentage recoveries were 100.20% and 101.20% for PYR and DOX, respectively.

Characterization of doxylamine and pyrilamine metabolites via thermospray/mass spectrometry and tandem mass spectrometry.

Analysis of doxylamine N-oxide and pyrilamine N-oxide as synthetic standards and biologically derived metabolites by thermospray mass spectrometry (TSP/MS) provided [M + H]+ ions for each metabolite. TSP/tandem mass spectrometry (TSP/MS/MS) of the [M + H]+ ions provided fragment ions characteristic of these metabolites. In addition, TSP mass spectrometry and TSP/MS/MS analysis of ring-hydroxylated N-desmethyldoxylamine, N-desmethylpyrilamine and O-dealkylated pyrilamine is also reported. A fragmentation pathway for analysis by MS/MS of pyrilamine and its metabolites is also proposed. The results demonstrate the utility of TSP/MS for biologically derived metabolites of pyrilamine and doxylamine.

Formation of artifactual metabolites of doxylamine following acid hydrolysis.

This study describes the use of gas chromatographic-mass spectrometric, high-performance liquid chromatographic and capillary column gas chromatographic separation techniques in demonstrating the production of several artifactual compounds reported in the literature as metabolites of doxylamine. Rhesus monkey urinary extracts which contained doxylamine and doxylamine metabolites were examined with and without acid hydrolysis. The production of 1-phenyl-1-(2-pyridinyl)ethanol and 1-phenyl-1-(2-pyridinyl)ethylene under acid hydrolysis conditions was demonstrated. These artifactual products were shown to originate from the acid hydrolysis of 2-[1-phenyl-1-(2-pyridinyl)ethoxy] acetic acid and not from doxylamine.

Trace level determination of doxylamine in nonhuman primate plasma and urine by GC/NPD and HPLC.

Bendectin contains doxylamine succinate and is used for the treatment of nausea and vomiting in pregnant women. Trace level analytical chemical procedures for analysis of doxylamine in primate urine and plasma were required before toxicological tests with the drug in three species of nonhuman primates could be performed. A gas chromatographic procedure using a nitrogen phosphorus detector was developed to quantitate doxylamine in primate plasma at levels as low as 100 ppb. A high-pressure liquid chromatographic procedure was also developed to assay the drug in primate urine at levels as low as 250 ppb. Data from stability studies with the drug in plasma at -5 degrees and -20 degrees C, and recovery of the drug from Bendectin tablets, plasma, and urine are also presented.