Green micellar liquid chromatographic method for simultaneous determination of antihistaminic drugs tripelennamine hydrochloride and diphenhydramine in pharmaceutical gel.

A new green micellar liquid chromatographic method has been developed and validated for the simultaneous determination of diphenhydramine (DPH) and tripelennamine hydrochloride (TRP) using a micellar mobile phase consisting of 1 mM Tween 20 in phosphate buffer pH 4:isopropanol (85:15, %v/v). The method was linear in the range of 4-150 and 5-120 µg/mL for TRP and DPH, respectively. The method was successfully applied for the simultaneous determination of DPH and TRP in a laboratory-prepared gel containing all possible excipients with mean percent recoveries ± standard deviation of 100.346 ± 1.265 and 100.754 ± 1.117 for TRP and DPH, respectively. The method was validated according to the International Conference on Harmonization guidelines. The method is confirmed to have excellent greenness.

[A tribute to Carl Djerassi]. / Tributo a Carl Djerassi.

On January 15, 2015, Carl Djerassi, an extraordinary personality, died at the age of 91 years. He was born in Vienna, Austria, on October 29, 1923. His parents were physicians and probably he wanted to be also a physician, but sooner than later he chose to be a chemist. In 1939 he arrived to live to New York with his mother. In 1945 he became American citizen. Part of his work is the first commercial antihistamine, pyribenzamine, and the first successful combined oral contraceptive pill. With this editorial we make a tribute to this steroid pioneer.

El 30 de enero de 2015 falleció, a la edad de 91 años, Carl Djerassi, un personaje extraordinario. Nació en Viena, Austria, el 29 de octubre de 1923. Sus padres eran médicos y quizás por esa razón él también quería serlo, pero pronto escogió la química. En 1939 llegó con su madre a vivir a Nueva York y en 1945 se naturalizó estadounidense. Son obra suya el primer antihistamínico comercial (la piribenzamina) y el compuesto farmacológico de la píldora anticonceptiva. Sirva el presente editorial como un homenaje a este pionero de los esteroides sintéticos.

HPLC method for identification and quantification of three active substances in a dermatological preparation--Viosept ointment.

The study was aimed at developing a HPLC method to identify and quantify domiphen bromide, tripelennamine hydrochloride and clioquinol in Viosept ointment. The tested substances were successfully separated using Inertsil ODS-3 (250 x 4.6 mm, 5 µm) as a stationary phase and a gradient elution. Detection at 310 nm wavelength was applied for tripelennamine hydrochloride and clioquinol, and at 215 nm wavelength for domiphen bromide. Methods of extraction of the tested substances were developed: domiphen bromide and clioquinol were extracted with acetone from heated solutions, and tripelennamine hydrochloride was extracted in a hexane-water system. Validation procedure confirmed the method to be sufficiently selective, precise and accurate. Correlation coefficients of calibration curves pointed out that they were linear within the examined concentration range.

Cationic amphiphilic drugs are potent inhibitors of yeast sporulation.

Meiosis is a highly regulated developmental process that occurs in all eukaryotes that engage in sexual reproduction. Previous epidemiological work shows that male and female infertility is rising and environmental factors, including pollutants such as organic solvents, are thought to play a role in this phenomenon. To better understand how organic compounds interfere with meiotic development, the model organism Saccharomyces cerevisiae was exposed to 446 bioactive molecules while undergoing meiotic development, and sporulation efficiency was quantified employing two different high-throughput assays. 12 chemicals were identified that strongly inhibited spore formation but did not interfere with vegetative growth. Many of these chemicals are known to bind to monoamine-receptors in higher eukaryotes and are cationic amphiphilic drugs. A detailed analysis of one of these drugs, tripelennamine, revealed that it induces sporulation-specific cytotoxicity and a strong inhibition of meiotic M phase. The drug, however, only mildly interfered with pre-meiotic DNA synthesis and the early meiotic transcriptional program. Chemical-genomic screening identified genes involved in autophagy as hypersensitive to tripelennamine. In addition, we found that growing and sporulating yeast cells heterozygous for the aminophospholipid translocase, NEO1, are haploinsufficient in the presence of the drug.

pH-dependent complexation of histamine H1 receptor antagonists and human serum albumin studied by UV resonance Raman spectroscopy.

UV resonance Raman spectroscopy was used to characterize the binding of three first-generation histamine H(1) receptor antagonists-tripelennamine (TRP), mepyramine (MEP), and brompheniramine (BPA)-to human serum albumin (HSA) at pH 7.2 and pH 9.0. Binding constants differ at these pH values, which can be ascribed to the different extent of protonation of the ethylamino side chain of the ligands. We have recently shown [Tardioli et al. J. Raman Spectrosc. 2011, 42, 1016-1024] that for the solution conformation of TRP and MEP the side chain plays an important role by allowing an internal hydrogen bond with the aminopyridine nitrogen in TRP and MEP. Results presented in this paper suggest that the existence of such molecular structures has serious biological significance on the binding affinity of those ligands to HSA. At pH 7.2, only the stretched conformers of protonated TRP and MEP bind in HSA binding site I. Using UV absorption data, we derived binding constants for the neutral and protonated forms of TRP to HSA. The neutral species seems to be conjugated to a positive group of the protein, affecting both the tryptophan W214 and some of the tyrosine (Y) vibrations. BPA, for which the structure with an intramolecular hydrogen bonded side chain is not possible, is H bound to the indole ring nitrogen of W214, of which the side chain rotates over a certain angle to accommodate the drug in site I. We propose that the protonated BPA is also bound in site I, where the Y150 residue stabilizes the presence of this compound in the binding pocket. No spectroscopic evidence was found for conformational changes of the protein affecting the spectroscopic properties of W and Y in this pH range.

Medullary pain facilitating neurons mediate allodynia in headache-related pain.

OBJECTIVE: To develop and validate a model of cutaneous allodynia triggered by dural inflammation for pain associated with headaches. To explore neural mechanisms underlying cephalic and extracephalic allodynia. METHODS: Inflammatory mediators (IM) were applied to the dura of unanesthetized rats via previously implanted cannulas, and sensory thresholds of the face and hind-paws were characterized. RESULTS: IM elicited robust facial and hind-paw allodynia, which peaked within 3 hours. These effects were reminiscent of cutaneous allodynia seen in patients with migraine or other primary headache conditions, and were reversed by agents used clinically in the treatment of migraine, including sumatriptan, naproxen, and a calcitonin gene-related peptide antagonist. Consistent with clinical observations, the allodynia was unaffected by a neurokinin-1 antagonist. Having established facial and hind-paw allodynia as a useful animal surrogate of headache-associated allodynia, we next showed that blocking pain-facilitating processes in the rostral ventromedial medulla (RVM) interfered with its expression. Bupivacaine, destruction of putative pain-facilitating neurons, or block of cholecystokinin receptors prevented or significantly attenuated IM-induced allodynia. Electrophysiological studies confirmed activation of pain-facilitating RVM "on" cells and transient suppression of RVM "off" cells after IM. INTERPRETATION: Facial and hind-paw allodynia associated with dural stimulation is a useful surrogate of pain associated with primary headache including migraine and may be exploited mechanistically for development of novel therapeutic strategies for headache pain. The data also demonstrate the requirement for activation of descending facilitation from the RVM for the expression of cranial and extracranial cutaneous allodynia, and are consistent with a brainstem generator of allodynia associated with headache disorders.

Involvement of histamine H1 and H2 receptors in the regulation of STAT-1 phosphorylation: inverse agonism exhibited by the receptor antagonists.

Signal transducer and activator of transcription-1 (STAT1) is a latent signal transducer protein which, on phosphorylation, is translocated from the cytoplasm to the nucleus and is subsequently activated. This study was designed to determine the involvement of histamine receptors in histamine-mediated effect on STAT1 phosphorylation. It is known that the actions of histamine mediated through H1 and H2 receptors are dependent on their respective downstream pathways, Ca(2+)-PKC and cAMP-PKA. In this study, we investigated the significance of PKA in STAT1 phosphorylation. C57BL/6 mouse splenocytes were isolated and treated with histamine (10(-7)-10(-4) M) and then activated with PMA (phorbol 12 myristate 13-acetate) plus ionomycin. The phosphorylated STAT1 levels were analyzed by immunoblotting. Histamine receptor agonists amthamine and betahistine, histamine receptor antagonists pyrilamine maleate, tripelennamine, ranitidine, cimetidine and thioperamide, cAMP agonists N(6), 2'-0-dibutyryladenosine-3',5'-cyclic monophosphate sodium salt (db-cAMP) and forskolin, protein kinase A inhibitors N-(2-[p-bromocinnamylamino]ethyl)-5-isoquinoline-sulfonamide (H89) and Rp diastereomer of adenosine cyclic 3',5'-phosphorothioate (RpcAMPs) and tyrosine kinase inhibitor tyrphostin were used to identify the upstream signal transduction pathways. We observed that histamine augmented the phosphorylation of STAT1 through both H1 and H2 receptors. Furthermore, H1 and H2 receptor antagonists displayed inverse agonism. Ca(2+)-PKC-induced phosphorylation of STAT1 was completely inhibited by H89 and significantly inhibited by RpcAMPs. DbcAMP and forskolin augmented the Ca(2+)-PKC-induced STAT1 phosphorylation thus suggesting a convergent crosstalk between the two histamine receptor signaling pathways, PKA and PKC.

Role of N-methyl-D-aspartate receptors in gastric mucosal blood flow induced by histamine.

Ionotropic N-methyl-D-aspartate (NMDA) receptor agonists, L-aspartic acid (L-Asp) and NMDA, have been shown to inhibit histamine-stimulated acid secretion, but their effect on gastric mucosal blood flow (GMBF) is largely unknown. The aim of this study was to investigate whether L-Asp and NMDA inhibit histamine-stimulated GMBF and to examine the expression patterns of NMDA receptor subunits NR1, NR2A, and NR2B in rat stomach. Laser Doppler flowmetry was used to measure gastric blood flow in anesthetized rats. The GMBF was assessed during an intravenous infusion of histamine in the presence of tripelennamine. The effects of L-Asp and NMDA on histamine-induced gastric blood flow were examined. In addition, the distribution patterns of NR1-, NR2A-, and NR2B-contaning NMDA receptors in rat stomach were determined immunohistochemically by using specific antibodies against NR1, NR2A, and NR2B. Histamine-induced enhancement of GMBF depended on acid secretion and the activation of H(2)-receptors. Neither L-Asp nor NMDA had an effect on the spontaneous GMBF. However, L-Asp and NMDA reduced the histamine-induced increase in GMBF. DL-2-amino-5-phosphonopentanoic acid (AP-5), an NMDA receptor antagonist; and prazosin, an alpha(1)-receptor antagonist; but not propanolol, a beta(2)-receptor antagonist; or yohimbine, a alpha(2)-receptor antagonist; reversed the inhibitory effect of L-Asp and NMDA on the histamine-induced increase in GMBF. Therefore, L-Asp and NMDA inhibit histamine-induced GMBF via a mechanism involving the activation of NMDA receptors and alpha(1)- adrenoceptors. The fact that NMDA receptor subunits NR1, NR2A, and NR2B were found to be localized in the rat stomach as visualized immunohistochemically with specific antibodies against NR1, NR2A, and NR2B is consistent with this hypothesis.

Mast cell--pituitary interaction: modulation by serine phospholipids.

The influence of mast cell activation on the secretion of prolactin has been studied in rats receiving lysophosphatidylserine, a natural occurring phospholipid with secretagogue activity in these cells. After the i.v. injection of lysophosphatidylserine (10 mg/kg) a plasma prolactin peak correlates with an increased blood histamine level. Following the secretory event, which is inhibited by the H1 anti-histamine tripelenamine, plasma prolactin level drops below the basal line. Repeated lysophosphatidylserine administrations induce mast cell desensitisation, thus reducing also the pituitary response. Under these conditions a decrease in prolactin basal level is still observed, although the pituitary stores of this hormone are preserved. Control tests in vitro with lysophosphatidylserine, show that the diacyl lysophosphatidylserine derivative amplifies the inhibitory effect of dopamine on prolactin secretion from isolated pituitaries. The data suggests that lysophosphatidylserine induces prolactin secretion through mast cell activation. After this event, the reacylation of this phospholipid into lysophosphatidylserine in the pituitary membrane may enhance the inhibitory control by dopamine.