Development and validation of an LC-MS/MS method for quantifying diamorphine and its major metabolites 6-monoacetylmorphine, morphine, morphine-3-glucuronide, and morphine-6-glucuronide in human plasma

Diamorphine, commonly known as heroin, is a semi-synthetic opioid analgesic. In the context of heroin-assisted treatment for opioid-dependent patients, diamorphine is mostly administered intravenously. However, recent attention has shifted towards intranasal administration as a better-tolerated alternative to the intravenous route. Here, we developed and validated a rapid bioanalytical method for the simultaneous quantification of diamorphine and its major metabolites 6-monoacetylmorphine, morphine, morphine-3-glucuronide, and morphine-6-glucuronide in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A straightforward protein precipitation extraction step was used for sample preparation. Chromatographic analyte separation was achieved using a Kinetex EVO C18 analytical column and a mobile phase gradient comprising an aqueous solution of ammonium hydrogen carbonate and methanol supplied with formic acid. Employing positive electrospray ionization and scheduled multiple reaction monitoring, we established a quantification range of 1-1,000 ng/mL for all analytes. Our validation results demonstrate a mean intra-assay accuracy of 91-106% and an intra-assay precision (CV) between 2 and 9% for all analytes and over three validation runs. The method exhibits a high extraction recovery (> 87%) and a negligible matrix effect (99-125%). Furthermore, no interferences with endogenous plasma compounds were detected. Lastly, we applied the method to assess the plasma concentrations of an opioid-dependent patient after the intranasal administration of diamorphine in a clinical study. In summary, we have successfully developed a rapid, highly reliable, and straightforward bioanalytical method for quantifying diamorphine and its metabolites in low amounts of clinical plasma samples.

Acute effects of intravenous DMT in a randomized placebo-controlled study in healthy participants

N,N-dimethyltryptamine (DMT) is distinct among classic serotonergic psychedelics because of its short-lasting effects when administered intravenously. Despite growing interest in the experimental and therapeutic use of intravenous DMT, data are lacking on its clinical pharmacology. We conducted a double-blind, randomized, placebo-controlled crossover trial in 27 healthy participants to test different intravenous DMT administration regimens: placebo, low infusion (0.6 mg/min), high infusion (1 mg/min), low bolus + low infusion (15 mg + 0.6 mg/min), and high bolus + high infusion (25 mg + 1 mg/min). Study sessions lasted for 5 h and were separated by at least 1 week. Participant's lifetime use of psychedelics was ≤20 times. Outcome measures included subjective, autonomic, and adverse effects, pharmacokinetics of DMT, and plasma levels of brain-derived neurotropic factor (BDNF) and oxytocin. Low (15 mg) and high (25 mg) DMT bolus doses rapidly induced very intense psychedelic effects that peaked within 2 min. DMT infusions (0.6 or 1 mg/min) without a bolus induced slowly increasing and dose-dependent psychedelic effects that reached plateaus after 30 min. Both bolus doses produced more negative subjective effects and anxiety than infusions. After stopping the infusion, all drug effects rapidly decreased and completely subsided within 15 min, consistent with a short early plasma elimination half-life (t_1/2α) of 5.0-5.8 min, followed by longer late elimination (t_1/2β = 14-16 min) after 15-20 min. Subjective effects of DMT were stable from 30 to 90 min, despite further increasing plasma concentrations, thus indicating acute tolerance to continuous DMT administration. Intravenous DMT, particularly when administered as an infusion, is a promising tool for the controlled induction of a psychedelic state that can be tailored to the specific needs of patients and therapeutic sessions.Trial registration: ClinicalTrials.gov identifier: NCT04353024.

Differences in clinical features associated with cannabis intoxication in presentations to European emergency departments according to patient age and sex

OBJECTIVE

To investigate if clinical features associated with acute cannabis intoxication in patients presenting to Emergency Departments for medical assistance differ according to patient age and sex.

METHODS

We analysed presentations in the Euro-DEN Plus dataset from 2014 to 2019 in which cannabis was the only drug involved (except for alcohol), and age, sex and alcohol co-ingestion had been recorded. Age was considered as categorical (five groups; <20, 20-29, 30-39, 40-49 and ≥50 years), and sex as binary variable (male/female). We evaluated 12 key clinical features recorded during emergency department (ED) care. Risks of presenting with each of these clinical features according to patient age and sex were calculated by logistic regression models, and adjusted for sex, age and alcohol co-ingestion.

RESULTS

4,268 of 43,633 Euro-DEN presentations (9.8%) fulfilled the inclusion criteria (median age: 26 years (IQR = 20-34), 70% male, 52% co-ingested alcohol). The frequency of clinical features was: anxiety 28%, vomiting 24%, agitation 23%, palpitations 14%, reduced consciousness 13%, acute psychosis 9%, hallucinations 9%, chest pain 7%, headache 6%, hypotension 4%, hypertension 3% and seizures 2%. Patients younger than 20 years more frequently had vomiting (34.7% of cases), reduced consciousness (21.5%), and headache (10.8%); and less frequently acute psychosis (5.5%). Patients older than 49 years more often had hypotension (6.5%) and less frequently vomiting (20%), anxiety (14%), agitation (14%) and reduced consciousness (10%). Males more frequently presented with hypertension (3.7 vs. 1.5%; OR = 2.311, 95%CI = 1.299-3.816), psychosis (10.4 vs 6.3%; 1.948, 1.432-2.430), chest pain (8.1 vs 4.5%; 1.838, 1.390-2.430) and seizures (2.5 vs 1.4%; 1.805, 1.065-3.060), and less frequently with vomiting (21.8 vs 28.2%; 0.793, 0.677-0.930), anxiety (25.4 vs 32.3%; 0.655, 0.561-0.766) and hypotension (2.9 vs 5.8%; 0.485, 0.350-0.671).

CONCLUSIONS

The prevalence of some clinical features typically associated with acute cannabis intoxication differed according to age and sex. The causes for these differences should be further investigated in order to better understand the pathophysiology of cannabis-related acute toxicity, and they may be relevant particularly for developing prevention campaigns and for treatment in specific sex and/or age groups.

Epitope-Specific Anti-C1q Autoantibodies in Systemic Lupus Erythematosus

Objective

In patients with systemic lupus erythematosus (SLE) complement C1q is frequently targeted by autoantibodies (anti-C1q), that correlate best with active renal disease. Anti-C1q bind to largely unknown epitopes on the collagen-like region (CLR) of this highly functional molecule. Here we aimed at exploring the role of epitope-specific anti-C1q in SLE patients.

Methods

First, 22 sera of SLE patients, healthy controls and anti-C1q positive patients without SLE were screened for anti-C1q epitopes by a PEPperMAP^® microarray, expressing CLR of C1q derived peptides with one amino acid (AA) shift in different lengths and conformations. Afterwards, samples of 378 SLE patients and 100 healthy blood donors were analyzed for antibodies against the identified epitopes by peptide-based ELISA. Relationships between peptide-specific autoantibodies and SLE disease manifestations were explored by logistic regression models.

Results

The epitope mapping showed increased IgG binding to three peptides of the C1q A- and three of the C1q B-chain. In subsequent peptide-based ELISAs, SLE sera showed significantly higher binding to two N-terminally located C1q A-chain peptides than controls (p < 0.0001), but not to the other peptides. While anti-C1q were associated with a broad spectrum of disease manifestations, some of the peptide-antibodies were associated with selected disease manifestations, and antibodies against the N-terminal C1q A-chain showed a stronger discrimination between SLE and controls than conventional anti-C1q.

Conclusion

In this large explorative study anti-C1q correlate with SLE overall disease activity. In contrast, peptide-antibodies are associated with specific aspects of the disease suggesting epitope-specific effects of anti-C1q in patients with SLE.