Identification of phenothiazine antihistamines and their metabolites in urine

A novel approach to investigate the combinatorial effects of TLK1 (Tousled-Like Kinase1) inhibitors with Temozolomide for glioblastoma therapy

Glioblastoma multiforme (GBM) is an aggressive, incurable brain tumor with poor prognosis and limited treatment options. Temozolomide (TMZ) is the standard chemotherapeutic treatment for GBM, but its efficacy has drawn strong criticism from clinicians due to short survival gains and frequent relapses. One critical limitation of TMZ therapy is the hyperactivation of DNA repair pathways, which over time neutralizes the cytotoxic effects of TMZ, thus highlighting the urgent need for new treatment approaches. Addressing this, our study explores the therapeutic potential of in-house-designed phenothiazine-based Tousled-like kinase-1 (TLK1) inhibitors for GBM treatment. TLK1, overexpressed in GBM, plays a role in DNA repair. Phenothiazines are known to cross the blood-brain barrier (BBB). Among all molecules, J54 was identified as a potential lead molecule with improved cytotoxicity. In the context of O6-methylguanine-DNA methyltransferase (MGMT)-deficient GBM cells, the combined administration of phenothiazines and TMZ exhibited a collective reduction in clonogenic growth, coupled with anti-migratory and anti-invasion effects. Conversely, in MGMT-proficient cells, phenothiazine monotherapy alone showed reduced clonogenic growth, along with anti-migratory and anti-invasion effects. Notably, a synergistic increase in γH2AX levels and concurrent attenuation of DNA repair upon combinatorial exposure to TMZ and J54 were observed, implying increased cytotoxicity due to sustained DNA strand breaks. Overall, this study provides new insights into TLK1 inhibition for GBM therapy. Collectively, these findings indicate that TLK1 is one of the upregulated kinases in GBM and phenothiazine-based TLK1 inhibitors could be a promising treatment option for GBM patients.

Innovative On-DNA Synthesis of Sulfides and Sulfoximines: Enriching the DEL Synthesis Toolbox

DNA-encoded library (DEL) technologies enable the fast exploration of gigantic chemical space to identify ligands for the target protein of interest and have become a powerful hit finding tool for drug discovery projects. However, amenable DEL chemistry is restricted to a handful of reactions, limiting the creativity of drug hunters. Here, we describe a new on-DNA synthetic pathway to access sulfides and sulfoximines. These moieties, usually contemplated as challenging to achieve through alkylation and oxidation, can now be leveraged in routine DEL selection campaigns.

Enantiomeric separation of oxomemazine in rabbit plasma by ultra-fast LC and application in a stereoselective pharmacokinetic study

Aim: Ultra-fast LC was used to establish a new bioanalytical method for enantiomeric separation of oxomemazine. Methods: The proposed study was carried out using the ultra-fast LC technique with an amylose chiral column. The bioanalytical approach was used in rabbit plasma following US FDA regulations and then extended to oxomemazine enantiomeric separation using metronidazole as the internal standard. Results: The retention times of (R)-oxomemazine, (S)-oxomemazine and the internal standard were found to be 9.511, 10.712 and 6.503 min, respectively. Within-run and between-run precision (percent relative standard deviation) was found to be in the range of 0.018-0.102% for (R)-oxomemazine and 0.028-0.675% for (S)-oxomemazine, whereas accuracy (%) was found to be in the range of 95.971-99.720% for (R)-oxomemazine and 97.199-103.921% for (S)-oxomemazine. Conclusion: The findings revealed that stereospecific distribution of oxomemazine enantiomers does not change significantly.

Binding of phenothiazines into allosteric hydrophobic pocket of human thioredoxin 1

Thioredoxins are multifunctional oxidoreductase proteins implicated in the antioxidant cellular apparatus and oxidative stress. They are involved in several pathologies and are promising anticancer targets. Identification of noncatalytic binding sites is of great interest for designing new allosteric inhibitors of thioredoxin. In a recent work, we predicted normal mode motions of human thioredoxin 1 and identified two major putative hydrophobic binding sites. In this work we investigated noncovalent interactions of human thioredoxin 1 with three phenotiazinic drugs acting as prooxidant compounds by using molecular docking and circular dichroism spectrometry to probe ligand binding into the previously predicted allosteric hydrophobic pockets. Our in silico and CD spectrometry experiments suggested one preferred allosteric binding site involving helix 3 and adopting the best druggable conformation identified by NMA. The CD spectra showed binding of thioridazine into thioredoxin 1 and suggested partial helix unfolding, which most probably concerns helix 3. Taken together, these data support the strategy to design thioredoxin inhibitors targeting a druggable allosteric binding site.

Phenothiazine molecule provides the basic chemical structure for various classes of pharmacotherapeutic agents

The chemical structure of phenothiazine provides a most valuable molecular template for the development of agents able to interact with a wide variety of biological processes. Synthetic phenothiazines (with aliphatic, methylpiperazine, piperazine-ethanol, piperazine-ethyl, or piperidine side-chain) and/or phenothiazine-derived agents e.g., thioxanthenes, benzepines, imonostilbenes, tricyclic antidepressants, dimetothiazine, and cyproheptadine have been effective in the treatment of a number of medical conditions with widely different etiology. These include various currently clinically used drugs for their significant antihistamic, antipsychotic, anticholinergic (antiparkinson), antipruritic, and/or antiemetic properties. They are also employed, although to a minor extent, as antidepressants, antispasmodics, analgesics, and antiarrhythemics. Some of these agents are also useful as anti-inflammatory, coronary vasodilator, radioprotective, sedative, antitussive, and skeletal muscle-relaxing medication. Still, others show different degrees of effectiveness as antibacterials, anthelmintics, antimalarials, or local anesthetics; a few are valuable in the control of acute migraine attacks and intractable hiccough. Adding to the seemingly ever-expanding therapeutic use of phenothiazine derivatives, a number of "old" and newly synthesized compounds e.g., "half-mustard-type" and benzo[alpha]phenothiazines, appear to be helpful as multidrug resistance modifiers, a property of particular importance in cancer chemotherapy. Some phenothiazines inhibit human plasmatic leucine-enkephalin aminopeptidase(s), enzymes known to regulate the turnover rate of a wide range of bioactive substances. These findings could lead to the design of new therapeutic treatment modalities for conditions such as Alzeimer's and Creutzfeldt-Jakob disease. Hopefully, this work will help to the rational design of new and improved pharmacological approaches based on a better understanding of the correlation between chemical structure, pharmacodynamic properties, and pharmacological activity of various phenothiazines and phenothiazine-derived classes of drugs.

Analysis of certain tranquilizers in biological fluids

A review with 282 references is presented that deals with the reported methods of analysis of phenothiazines, thioxanthenes, and benzodiazepine derivatives of pharmaceutical interest. The review includes the methods adapted in biological fluids.

Determination of phenothiazines in human body fluids by solid-phase microextraction and liquid chromatography/tandem mass spectrometry

Eleven phenothiazine derivatives with heavy side-chains were found to be extractable from human whole blood and urine samples by solid-phase microextraction (SPME) with a polyacrylate-coated fiber. The fiber was then injected into the desorption chamber of an SPME-liquid chromatography (LC) interface for LC/tandem mass spectrometry (MS/MS) with positive ion electrospray (ES) ionization. All compounds formed base peaks due to [M + 1](+) ions by LC/ES-MS/MS. By use of LC/ES-MS/MS, the product ions produced from each [M + 1](+) ion showed base peaks due to side-chain liberation. Selected reaction monitoring (SRM) and selected ion monitoring (SIM) were compared for the detection of the 11 phenothiazine derivatives from human whole blood and urine. SRM showed much higher sensitivity than SIM for both types of sample. Therefore, a detailed procedure for the detection of drugs by SRM with SPME-LC/MS/MS was established and carefully validated. The extraction efficiencies of the 11 phenothiazine derivatives spiked into whole blood and urine were 0. 0002-0.12 and 2.6-39.8%, respectively. The regression equations for the 11 phenothiazine derivatives showed excellent linearity with detection limits of 0.2-200 ng ml(-1) for whole blood and 4-22 pg ml(-1) for urine. The intra- and inter-day precisions for whole blood and urine samples were not greater than 15.1%. The data obtained after oral administration of perazine or flupentixol to a male subject are presented.

Systematic toxicological analysis of drugs and their metabolites by gas chromatography-mass spectrometry

Gas chromatographic-mass spectrometric (GC-MS) procedures for the systematic toxicological analysis of several categories of drugs relevant to clinical toxicology, forensic toxicology and doping control are reviewed. Papers from 1981 to 1991 are taken into consideration. They describe the detection of acute or chronic intoxication and the detection of drug abuse. Screening procedures are included for the following categories: barbiturates and other sedative-hypnotics, anticonvulsants, benzodiazepines, antidepressants, phenothiazine and butyrophenone neuroleptics, central stimulants (amphetamines, cocaine), hallucinogens (LSD, phencyclidine, tetrahydrocannabinol), opioid (narcotic) and other potent analgesics, non-opioid analgesics, antihistamines (histamine H1-receptor blockers), antiparkinsonian drugs, beta-blockers (beta-adrenoceptor blockers), antiarrhythmics (class I and IV), diuretics, laxatives and their metabolites. Methods for confirmation of results obtained by screening procedures using immunoassay or chromatographic techniques are also included. GC-MS procedures for the simultaneous detection of several categories of drugs, the so-called "general unknown analysis", are reviewed. The toxicological question to be answered and the consequence for the choice of an adequate method, the sample preparation and the chromatography itself are discussed. The basic information about the biosample assayed, work-up, GC column, mass spectral detection mode, reference data and sensitivity of each procedure are summarized in tables, arranged according to the category of drug. Examples of typical GC-MS applications are presented. Fragment ions that are suitable for mass spectral screening for particular categories of drugs and for general unknown are tabulated.

Chromatography of histamine H1- and H2-receptor blockers in biosamples

This paper reviews thin-layer chromatographic, high-performance liquid chromatographic, gas chromatographic and gas chromatographic-mass spectrometric procedures for the identification and quantification of sixty histamine H1- and ten H2-receptor blockers in biosamples, published from 1984 to 1989. The biomedical importance of the published procedures and consequences for their choice, the sample preparation and the chromatography itself are discussed. The fundamental information about the biosample assayed, work-up, stationary and mobile phase, detection mode and sensitivity of each procedure is summarized in seven tables. They are arranged according to the chromatographic method and the category of histamine receptor blockers. Examples of typical chromatographic separations are presented in three figures.

Detection of anticonvulsants and their metabolites in urine within a "general unknown" analysis procedure using computerized gas chromatography-mass spectrometry

Detection of the anticonvulsants carbamazepine, clonazepam, diazepam, ethosuximide, mephenytoin, mesuximide, methylphenobarbital, phenobarbital, phenytoin, primidone, propylhexedrine, sultiame, trimethadion and their metabolites in urine is described. The method presented is integrated in a general screening procedure (general unknown analysis) for several groups of drugs, detecting several hundred drugs and over 1000 metabolites. It includes cleavage of conjugates by acid hydrolysis, isolation by liquid-liquid extraction, derivatization by acetylation, separation by capillary gas chromatography and identification by computerized mass spectrometry. Using mass chromatography with the selective ions m/z 58, 104, 113, 117, 165, 193, 204 and 246, the possible presence of anti-convulsants and/or their metabolites was indicated. The identity of positive signals in the reconstructed mass chromatograms was confirmed by a visual or computerized comparison of the stored full mass spectra with the reference spectra. The sample preparation, mass chromatograms, reference mass spectra and gas chromatographic retention indices are documented.

Identification and differentiation of barbiturates, other sedative-hypnotics and their metabolites in urine integrated in a general screening procedure using computerized gas chromatography-mass spectrometry

A gas chromatographic-mass spectrometric procedure is described for the identification and differentiation of sedative-hypnotics and their metabolites in urine. The following 24 barbiturates and thirteen other hypnotics could be detected: acecarbromal, allobarbital, amobarbital, aprobarbital, barbital, brallobarbital, bromisoval, (sec)butabarbital, butalbital, butobarbital, carbromal, clomethiazole, crotylbarbital, cyclobarbital, cyclopentobarbital, diethylallylacetamide, dipropylbarbital, glutethimide, guaifenesin, ethinamate, heptabarbital, hexobarbital, meprobamate, methaqualone, metharbital, methohexital, methylphenobarbital, methyprylone, pentobarbital, phenobarbital, propallylonal, pyrithyldione, secobarbital, thiobutabarbital, thiopental, vinbarbital and vinylbital. The procedure presented is integrated in a general screening procedure (general unknown analysis) for several groups of drugs detecting over 300 drugs and over 1000 of their metabolites. It includes cleavage of conjugates by acid hydrolysis, isolation by liquid-liquid extraction, derivatization by acetylation, separation by capillary gas chromatography, and identification by computerized mass spectrometry. Using mass chromatography with the selected ions m/z 83, 117, 141, 167, 169, 207, 221 and 235, the presence of barbiturates, other hypnotics and/or their metabolites was indicated. The identity of positive signals in the reconstructed mass chromatograms was confirmed by a visual or computerized comparison of the stored full mass spectra with the reference spectra. The sample preparation, mass chromatograms, reference mass spectra and gas chromatographic retention indices are documented.

Identification of antiarrhythmic drugs and their metabolites in urine

Identification of the antiarrhythmic drugs ajmaline, aprindine, diltiazem, disopyramide, flecainide, gallopamil, lidocaine, lorcainide, mexiletine, phenytoin, prajmaline, propafenone, quinidine, sparteine, tocainide and verapamil and their metabolites in urine is described. After acid hydrolysis of the conjugates, extraction and acetylation, the urine samples were analysed by computerized gas chromatography-mass spectrometry. Using ion chromatography with the selective ions m/z 58, 72, 84, 86, 136, 224, 266, and 426, the possible presence of antiarrhythmic drugs and/or their metabolites was indicated. The identity of positive signals in the reconstructed ion chromatograms was confirmed by a visual or computerized comparison of the stored full mass spectra with the reference spectra. The ion chromatograms, reference mass spectra and gas chromatographic retention indices (OV-101) are documented. The method presented is integrated in a general screening procedure (general unknown analysis) for several groups of drugs.