A naive Bayesian classifier (NBC) combined with principal component analysis (PCA) effectively differentiates the dose-dependent effects of certain groups of psychoactive drugs based on their impact on the amplitude-spectral characteristics of electrocorticograms (ECoG) in rats. This approach has been shown to be useful for pharmacological screening of agents with unknown or poorly understood activity. Despite previously obtained optimistic results, classification determination for some drugs was inaccurate, necessitating the search for possible ways to improve the predictive effectiveness of the proposed algorithm. One possible approach would be to use as input quantitative data not only the impact of the psychoactive drugs studied on the amplitude-spectral characteristics of ECoG but also connectivity changes, including the average coherence power of different pairs of leads. The aim of this study was to compare the accuracy of NBC in classifying the pharmacological mechanism of action of agents with well-known mechanisms (test set) using pharmaco-EEG data on changes in the amplitude-spectral characteristics of ECoG, coherence, and the combined use of two data sets. Materials and methods. Experiments were performed on Wistar rats with chronically implanted ECoG electrodes. The training set, relative to which the effects of the pharmacological agents from the test set were classified, were the matrices of effects of 12 pharmacological agents: the NMDA antagonist dizocilpine, the D2/D3 antagonists haloperidol and sulpiride, the M-anticholinergic tropicamide, the H1/5HT2A receptor blocker hydroxyzine, the acetylcholinesterase inhibitor galantamine, the alpha-2 adrenergic agonist dexmedetomidine, the alpha-2 adrenergic antagonist atipamezole, the adenosine receptor blocker caffeine and the GABA-mimetics aminophenylbutyric acid (phenibut), bromdihydrochlorophenylbenzodiazepine (phenazepam) and 5-ethyl-5-phenyl-2,4,6(1H,3H,5H)-pyrimidinetrione. The test set included various drugs with tropism for the targets of the training set drugs: dopamine receptor antagonists chlorpromazine, droperidol, tiapride and raclopride, H1-histamine blockers diphenhydramine and promethazine, 5-HT2-receptor blockers ritanserin and glemenserin, acetylcholinesterase inhibitor ipidacrine, alpha2-adrenergic receptor antagonist yohimbine, alpha2-adrenergic agonists medetomidine and xylazine, GABA-mimetics 5-ethyl-5-(1-methylbutyl)-2,4,6(1H,3H,5H)-pyrimidinetrione and chloral hydrate. The analysis of the ECoG signal included the calculation of 132 amplitude-spectral characteristics and 75 coherence indicators, which, using the PCA, led to new integrative indicators used for further classification of the NBC. Results and discussion. For each drug in the test set, the median similarity probability with a particular group from the training set was calculated, which was used to assess the classification quality. It was found that, when using the amplitude-spectral characteristics of ECoG, the proposed methodological approach allows for the identification of the ECoG effects of several groups of psychoactive drugs, including D2/D3-dopamine, M-cholinergic, H1-histamine, and 5-HT2-serotonin receptor blockers, AChE inhibitors, GABA-mimetics, and alpha-2-adrenergic receptor agonists and antagonists. This approach enabled the correct classification of 18 of 24 groups in the test set. When using changes in coherence indices as the initial data, the classification accuracy also amounted to 18 of 24 groups. When combining the two data sets, the number of correctly identified NBC groups was 20 of 24 groups. When comparing the classification during training (confusion matrix), it was found that coherence data or adding coherence data to the data based on changes in amplitude-spectral characteristics leads to a statistically significant (p < 0.01 in both cases) increase in accuracy. Conclusions. The obtained data demonstrated high accuracy in classifying the pharmacological activity of the test sample drugs using any of the three compared approaches. Despite the lack of statistically significant differences between them, classification based on the combined dataset demonstrated a higher number of "correct" similarities. This allows us to recommend the approach based on combined data of drug effects on amplitude-spectral characteristics and coherence as the most promising for further studies using pharmaco-EEG screening.

A simple, rapid, sensitive, and stability-indicating reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the quantitative determination of promethazine hydrochloride (HCl) in pharmaceutical formulations. Chromatographic separation was achieved using a SunFire® C18 column (4.6 × 250 mm, 5 µm) with a mobile phase consisting of acetonitrile and 0.1% orthophosphoric acid in water (80:20, v/v) at a flow rate of 1.0 mL/min. Detection was performed at 249 nm using a photodiode array detector. The developed method was validated according to the International Council for Harmonisation Q2 guidelines with respect to specificity, linearity, precision, accuracy, robustness, limit of detection, and limit of quantitation.The method exhibited good linearity over the concentration range of 2-64 µg/mL with a correlation coefficient (R[2]) of 0.9993. The percentage relative standard deviation for precision studies was below 2%, indicating satisfactory repeatability and reproducibility. Forced degradation studies were performed under acidic, alkaline, neutral, oxidative, and thermal stress conditions to evaluate the stability indicating capability of the method. Additional chromatographic peaks corresponding to degradation products were observed in acid, base, neutral, and oxidative stress conditions, while minimal degradation was observed under thermal stress. Furthermore, liquid chromatography-mass spectrometry (LC-MS) analysis was carried out to characterize the degradation products formed during stress studies. LC-MS results indicated that alkaline stress produced the highest degree of degradation, whereas thermal stress generated only minor residual impurities, confirming the relative stability of promethazine HCl under thermal conditions. The developed RP-HPLC method was found to be suitable for routine quality control analysis and stability assessment of promethazine HCl in pharmaceutical formulations.

Candidozyma auris (formerly Candida auris) is a global emerging fungal pathogen of significant global clinical and epidemiological concern. It is frequently associated with hospital outbreaks, largely due to its multidrug resistance, ability to persist on medical devices, and high potential for nosocomial transmission. This study investigated efflux pump inhibition as a potential strategy for controlling C. auris. The efflux pump inhibitor promethazine (PMZ) was evaluated against planktonic cells and mature biofilms of 15 clinical isolates. PMZ completely inhibited the planktonic growth of both azole-susceptible and azole-resistant C. auris strains at concentrations ranging from 32 to 64 μg/mL. Synergistic interactions between PMZ and either echinocandins or azoles were observed, resulting in effective inhibition of nearly all tested strains during planktonic phase growth. Additionally, PMZ at 4× MIC significantly disrupted mature biofilms of both azole-susceptible and azole-resistant strains. Mature biofilms were also susceptible to combinations of antifungals and PMZ. These findings indicate that efflux pump inhibition represents a promising therapeutic strategy for controlling infections caused by C. auris. PMZ may be considered a promising structural framework for the development of novel antifungal agents.

A molecularly imprinted polymer (MIP)-based quartz crystal microbalance (QCM) sensor was developed for the selective detection of promethazine (PMZ) through deliberate regulation of template-monomer interactions during the molecular imprinting process. Various functional monomer systems were systematically evaluated to optimize intermolecular recognition, among which the combination of 4-vinylpyridine (4-VP) and 2-acrylamido-2-methylpropanesulfonic acid (AAMPS) exhibited the strongest interaction toward PMZ. Furthermore, protonation of PMZ using hydrochloric acid significantly enhanced electrostatic complexation between the template and functional monomers, leading to improved pre-polymerization organization, more effective imprinting-site formation and high selectivity towards target analytes. The resulting MIP-QCM sensor exhibited a linear response toward PMZ over the concentration range of 50-2000 ppb with a correlation coefficient (R2) of 0.99148 and a detection limit of 27.4 ppb. The sensor demonstrated favorable selectivity against structurally related compounds, strong anti-interference performance under highly competitive matrix conditions, and excellent regeneration stability, retaining 97.9% of its original response after ten regeneration cycles. Recovery studies in spiked tap water and carbonated beverage samples yielded recoveries ranging from 94.7% to 112.6%. These results demonstrate that regulating template ionization and template-monomer interactions is an effective strategy for improving imprinting-site quality and molecular recognition performance. The proposed approach provides new insight into the rational design of highly selective MIPs for basic pharmaceutical compounds and offers a promising platform for environmental, pharmaceutical and forensic monitoring applications.

Many drugs that block voltage-gated K+ channels encoded by the human ether-à-go-go-related gene (hERG) can cause long QT syndrome and life-threatening cardiac arrhythmias, yet the molecular mechanisms that determine this risk remain unclear. A process that may counteract arrhythmogenic hERG block, termed facilitation, is common to many clinically approved hERG blockers, including nifekalant, amiodarone, promethazine, imipramine, nortriptyline, haloperidol, verapamil, carvedilol, metoprolol, propranolol, quinidine, fluoxetine, and chlorpheniramine. Facilitation is an increase in hERG current, under certain conditions, due to these blockers. Here, we propose that an agonism-while-blocking mechanism underpins facilitation. We focus on nifekalant, a class III antiarrhythmic drug and exemplar hERG blocker that induces facilitation. We tested the hypothesis that nifekalant opens hERG channel gates while blocking, and that unblocking of these open-yet-blocked channels results in supranormal hERG current. We developed rate-theory kinetic models to identify features of agonism-while-blocking that produce facilitation. We generated atomistic models that predict that nifekalant blocks the hERG conduction path while modulating the intracellular conduction gate. Voltage-clamp measurements revealed that agonism-while-blocking can result in nifekalant block and facilitation. We speculate that this agonism-while-blocking mechanism contributes to the relative safety of hERG blockers that induce facilitation.

Verapamil-sensitive fascicular tachycardia is a type of ventricular tachycardia (VT) involving the specialised cardiac conducting tissue. Drug overdose is an important cause to consider when assessing patients with a new presentation of a broad complex tachycardia. Multiple antihistamines have been implicated as pro-arrhythmic, but these tend to precipitate Torsades de Pointes via drug-induced QT prolongation. We present an educational case of a Verapamil-sensitive fascicular VT with typical electrocardiogram (ECG) characteristics, which developed immediately following an overdose of promethazine and which was terminated successfully with verapamil, in a young person with a structurally normal heart. There have been no previous published reports of promethazine precipitating a fascicular VT and we aim to highlight this unusual link and the benefits of early recognition and management of similar presentations.

First-generation H1 antihistamines have central nervous system penetration and anticholinergic activity, with potential side effects including sedation, cognitive impairment, and anterograde amnesia. First-generation antihistamines pose risks in driving under the influence of drugs (DUID) and drug-facilitated crimes (DFC) forensic casework. A liquid chromatography-tandem mass spectrometry method was developed and validated for five first-generation H1 antihistamines: chlorpheniramine, diphenhydramine, doxylamine, hydroxyzine, and promethazine. The calibration range was 1-200 ng/mL with a 1/x linear calibration model for quantitative compounds, and the limit of detection was determined to be 0.5 ng/mL for all compounds. Bias and precision were acceptable, with minor but acceptable suppression observed at low and high concentrations. No exogenous or endogenous interferences were observed. Carryover was not detected after a 400 ng/mL sample. Processed samples were determined to be stable 24 h after initial injection when stored in the refrigerated multi-sampler. Authentic forensic specimens from DUID and DFC investigations showed a wide range of concentrations for diphenhydramine. Selected case reports are presented to demonstrate the applicability of the method. The high percentage of polysubstance cases, range of concentrations, and delayed sample collection in DFC cases underscore the importance of a sensitive and reproducible method for these first-generation antihistamines, especially in human-performance casework.

Recently, abuse and fatal overdoses of over-the-counter (OTC) medications have become serious social and health issues worldwide. However, many drug components in OTC medications that are abused have different chemical structures from those assessed by commercially available rapid drug test kits. In this research, we focused on using dried blood spot (DBS) samples to develop a simple and accurate method for forensic toxicological analysis of drugs of interest in deaths by poisoning. We combined the DBS method with liquid chromatography coupled with electrospray ionization-tandem mass spectrometry to quantify eight OTC drug components (apronal, caffeine, chlorpheniramine, dextromethorphan, diphenhydramine, diprophylline, noscapine, and promethazine). The linearities of the calibration curves were good in the concentration range of 0.1-2.0 μg/mL. The method achieved repeatable and accurate quantification of the eight target drugs with intra- and inter-assay coefficients of variation of below 13.0% and 12.6%, respectively. Comparison with our general practice method showed good positive correlations at the quantifiable concentrations of all drugs. Furthermore, when applied to an actual case, it was possible to diagnose death by drug poisoning, confirming the usefulness of this method.

IntroductionSpaceflight may accelerate degradation of active pharmaceutical ingredients, raising concerns about medication stability during long-duration missions. This study assessed the potency of active pharmaceutical ingredients in a convenience sample of medications flown to the International Space Station alongside lot-matched terrestrial control samples.MethodsSpaceflight-exposed samples and terrestrial control samples were analyzed using ultra-high-performance liquid chromatography with tandem mass spectrometry. At the time of analysis, all medications were beyond their labeled expiration dates following prolonged storage and delayed laboratory testing. Medications included caffeine, diazepam, diphenhydramine, epinephrine, ketamine, lidocaine, naloxone, and promethazine in solid and liquid formulations. Percent difference between exposed and control samples was calculated, and absolute potency was evaluated relative to 95 to 105% and 80 to 120% ranges. Regression analyses examined associations of changes in the potency of active pharmaceutical ingredients with days in space and days expired.ResultsMost samples from both groups fell outside the 95 to 105% range. However, >90% remained within the broader 80 to 120% range. Average percent differences between spaceflight-exposed and ground control samples were generally within ±5% for most medications, suggesting limited relative potency differences despite prolonged spaceflight exposure. Epinephrine exhibited the most consistent reductions, averaging 10% lower potency than control samples. Regression analyses identified medication-specific associations with days expired and days in space but did not show a consistent pattern of spaceflight-associated potency loss.ConclusionWithin the limitations of this lot-matched, post-storage comparison, International Space Station exposure was not associated with large relative potency changes for most medications studied. Epinephrine represented the clearest exception and may require medication-specific stabilization strategies for long-duration space exploration missions.