5-HT2 Antagonist Activity Research Articles

Quetiapine Fumarate: A Review of Analytical Methods.

Atypical antipsychotics are newer second-generation antipsychotics with weak dopamine type 2 blocking but potent 5-HT2 antagonistic activity. They are considered first-line treatments for schizophrenia and gradually replace typical antipsychotics. Extrapyramidal side effects are minimal, and they tend to improve impaired cognitive function in psychotics. Quetiapine fumarate is an atypical antipsychotic drug used to treat schizophrenia, mania and depression in people with bipolar disorder combined with other drugs or alone. Quetiapine was developed in 1985 and approved for medical use in the USA in 1997. Thorough computer-aided literature, surveys revealed that numerous analytical methods were reported over the years. The present study reviews analytical methods with their validation parameters published during the last 22years (1999-2021) either as a single entity or combination in dosage form, and determination from biological samples. Novel strategies for increasing separation quality, such as QbD analysis and green spectroscopy, were discovered during the evaluation, and this review can be utilized for further research reference.

Synthesis, Preliminary Pharmacological and Acute Toxicity Studies of a New Series of 7-(2-(Benzo[d]thiazol-2-ylamino)ethoxy)-4-methyl-2H-chromen-2-one Derivatives with Atypical Antipsychotic Activity

The present study focused on the synthesis, preliminary pharmacological screening and acute toxicity testing of novel series of 7-(2-(benzo[d]thiazol-2-ylamino)ethoxy)-4-methyl-2H-chromen-2-one derivatives (4a-4k). This novel series was designated and synthesized by refluxing 2-amino benzothiazoles substituted derivatives (3a-3k) with 7-(2-chloroethoxy)-4-methyl-2H-chromen-2-one (2) in dry pyridine. All the synthesized compounds were screened and evaluated for dopamine D2 and serotonin 5HT2 antagonistic activity as a measure of atypical antipsychotic property. Compounds 4b, 4c, 4e, 4g and 4i have shown good preliminary pharmacological activity and these compounds were subjected to acute toxicity (lethal dose) studies for determining effective dose range using probit log scale method. The therapeutic index of the selected compounds was determined to compare with other series of compounds to select better active compound(s). The structures of all compounds were confirmed using spectral studies. All the synthesized compounds showed good dopamine D2 and serotonin 5HT2A receptor antagonist activity, which could indicate atypical antipsychotic activity. Compounds (4e) and (4b) with electron withdrawing substituents showed better atypical antipsychotic activity.

Synthesis and pharmacological activity of 10-alkylaminoethyl-2,3,4,10-tetrahydropyrimido[1,2-a]benzimidazoles

The synthesis of 10-chloroethyl-2,3,4,10-tetrahydropyrimido[1,2-a]benzimidazole was described. The nucleophilic substitution of the chlorine atom by various amines was studied. As a result, 10-alkylaminoethyl-substituted derivatives of this tricycle containing alkylamines and 4-substituted piperazines were obtained. These compounds exhibited 5-HT2 antagonist activity; platelet antiaggregant properties; and moderate P2Y1-antagonist, antiarrhythmic, and hypoglycemic action.

P.1.002 Role of 5-HT2A-receptor and α2-adrenoceptor blockade in the asenapine-induced elevation of prefrontal cortical monoamine outflow

1.1. There has been considerable research in the field of schizophrenia over the past few years with emphasis on the discovery of better drugs, particularly those with 5-HT2 antagonist activity.2.2. In an effort to enhance identification of such compounds and to further understand the contribution of 5-HT2 activity to the effects of antipsychotic drugs, a series of conventional, atypical and purported antipsychotic compounds were assessed as antagonists of DOI-induced behaviors in rats.3.3. DOI (l-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride) is an hallucinogen having high aIEnity and selectivity as an agonist at 5-HT2A/2C receptors. Over a 30-min period after injection, DOI (0.3 – 10.0 mg/kg; i.p.) produced dose-related behavioral effects including head-and-body shakes, forepaw tapping and skin-jerks. Effects of the antipsychotic drugs and other compounds (30 min pretreatment; i.p.) were examined against a fixed dose of DOI (3.0 mg/kg).4.4. In a dose-dependent manner, M100907 (MDL 100, 907), risperidone, haloperidol, clozapine, iloperidone, olanzapine, amperozide, remoxipride, ritanserin and the neurotensin agonist NT1 (NαleArg-Lys-Pro-Trp-Tle-Leu) antagonized each of the three behavioral effects of DOI. Drugs attenuating the head-and-body shakes were equally effective in blocking both forepaw tapping and skin-jerks indicating that these behaviors are mediated by similar mechanisms. The following compounds had either inconsistent or no effect on the DOI-induced behaviors: SB 200646A, citalopram, imipramine, fluoxetine, morphine, CP 99994, diazepam, ondansetron and SKF 97541.5.5. The data show that antipsychotic agents, as a drug class, effectively block the effects of DOI. These actions are selective, as a series of nine non-antipsychotic and centrally-acting drugs were generally inactive in the procedure.

ChemInform Abstract: Syntheses and 5-HT2 Antagonist Activity of Bicyclic 1,2,4-Triazol-3(2H) -one and 1,3,5-Triazine-2,4(3H)-dione Derivatives.

A series of bicyclic 1,2,4-triazol-3(2H)-one and 1,3,5-triazine-2,4(3H)-dione derivatives with a 4-[bis(4-fluoro-phenyl)methylene]piperidine or 4-(4-fluorobenzoyl)piperidine group has been prepared and tested for 5-HT2 and alpha 1 receptor antagonist activity. Among the compounds prepared, 2-[2-[4-[bis(4-fluorophenyl)methylene]-piperidin-1-yl]ethyl]- 5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyridin-3(2H)-one (7b) had the most potent 5-HT2 antagonist activity, which was greater than ritanserin (2), while 7b did not show alpha 1 antagonist activity in vivo. The central 5-HT2 receptor antagonism was approximately 1/30 that of 2 when tested for the ability to block head twitches induced by 5-hydroxytryptophan. Compound 21b, 3-[2-[4-(4-fluorobenzoyl)piperidin-1-yl]ethyl]-6,7,8,9-tetrahydro- 2H- pyrido[1,2-a]-1,3,5-triazine-2,4(3H)-dione also displayed potent 5-HT2 antagonist activity. The compound had moderate alpha 1 receptor antagonism, and the potency inhibiting head twitches was about one-third that of ketanserin (1). These results indicate that 5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyrimidin-3(2H)-one and 6,7,8,9-tetrahydro-2H-pyrido-[1,2-a]-1,3,5-triazine-2,4(3H)-dione ring systems are useful components of 5-HT2 antagonists.

Benzo[d][1,3] oxathiols: synthesis and biological evaluation as potential atypical antipsychotic agents

The present research paper reports the synthesis and biological evaluation of 6-(3-substitutedpropoxyl)benzo[d][1,3]oxathiol-2-ones as potential atypical antipsychotic agents. Accordingly, 10 derivatives with either amino or aryloxy substituents were synthesized. Potential antipsychotic activity of these compounds in terms of D2 antagonism was evaluated by their ability to inhibit apomorphine-induced climbing behavior in mice and 5-HT2 antagonistic activity of synthesized compounds was assessed by studying inhibition of 5-HTP-induced head twitches. Non-specific D2 blockade was evaluated by studying propensity of these compounds to produce catalepsy in mice. All the synthesized compounds were found to exhibit D2 and 5-HT2 antagonist activity in behavioral models. However, they also induced mild to severe catalepsy. Among the 10 compounds tested, 5b and 5e exhibited maximum ‘atypical antipsychotic activity like’ profile.

Perospirone in the treatment of patients with delirium

Perospirone is a recently developed atypical antipsychotic with potent serotonin 5-HT2 and dopamine D2 antagonist activity. Other atypical antipsychotics including risperidone, quetiapine and olanzapine have been widely used for treatment, not only for schizophrenia symptoms but also for delirium, because of their low potential to induce extrapyramidal disturbances. In the present study the effectiveness and safety of perospirone in patients with delirium are described. Thirty-eight patients with DSM-IV delirium were given open-label perospirone. To evaluate the usefulness of perospirone, scores from 13 severity items of the Delirium Rating Scale-Revised-98 were assessed. Data were gathered from October 2003 to September 2004. Perospirone was effective in 86.8% (33/38) of patients, and the effect appeared within several days (5.1 +/- 4.9 days). The initial dose was 6.5 +/- 3.7 mg/day and maximum dose of perospirone was 10.0 +/- 5.3 mg/day. There were no serious adverse effects. However, increased fatigue (15.2%), sleepiness (6.1%), akathisia (3.0%) and a decline in blood pressure (3.0%) were observed. It is proposed that perospirone may be another safe and effective atypical antipsychotic drug for the treatment of delirium symptoms in hospitalized patients. This is a preliminary open trial, and further randomized double-blind placebo-controlled tests are needed.

Selectivity of action of typical and atypical antipsychotic drugs as antagonists of the behavioral effects of 1-[2,5-dimethoxy-4-iodophenyl]-2-aminopropane (DOI)

1. 1. There has been considerable research in the field of schizophrenia over the past few years with emphasis on the discovery of better drugs, particularly those with 5-HT2 antagonist activity. 2. 2. In an effort to enhance identification of such compounds and to further understand the contribution of 5-HT2 activity to the effects of antipsychotic drugs, a series of conventional, atypical and purported antipsychotic compounds were assessed as antagonists of DOI-induced behaviors in rats. 3. 3. DOI (l-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride) is an hallucinogen having high aIEnity and selectivity as an agonist at 5-HT 2A/2C receptors. Over a 30-min period after injection, DOI (0.3 – 10.0 mg/kg; i.p.) produced dose-related behavioral effects including head-and-body shakes, forepaw tapping and skin-jerks. Effects of the antipsychotic drugs and other compounds (30 min pretreatment; i.p.) were examined against a fixed dose of DOI (3.0 mg/kg). 4. 4. In a dose-dependent manner, M100907 (MDL 100, 907), risperidone, haloperidol, clozapine, iloperidone, olanzapine, amperozide, remoxipride, ritanserin and the neurotensin agonist NT1 (N αleArg-Lys-Pro-Trp-Tle-Leu) antagonized each of the three behavioral effects of DOI. Drugs attenuating the head-and-body shakes were equally effective in blocking both forepaw tapping and skin-jerks indicating that these behaviors are mediated by similar mechanisms. The following compounds had either inconsistent or no effect on the DOI-induced behaviors: SB 200646A, citalopram, imipramine, fluoxetine, morphine, CP 99994, diazepam, ondansetron and SKF 97541. 5. 5. The data show that antipsychotic agents, as a drug class, effectively block the effects of DOI. These actions are selective, as a series of nine non-antipsychotic and centrally-acting drugs were generally inactive in the procedure.

Synthesis and pharmacological evaluation of pyrroloazepine derivatives as potent antihypertensive agents with antiplatelet aggregation activity.

A series of 1-aminoalkyl-pyrrolo[2,3-c]azepin-8-one derivatives was synthesized and evaluated as alpha 1 adrenergic and serotonin 2 (5-HT2) receptor antagonists, with the aim of finding a novel antihypertensive agent potently exhibiting both activities. Some compounds with a 4-[4-(4-fluorobenzoyl)piperidino]butyl group at the 1-position exhibited both activities, and varied significantly in terms of the substituents at the 4-position of the pyrroloazepine ring. Among the compounds obtained in this study, (E)-1-[4-[4-(4-fluorobenzoyl)piperidino]-butyl]-4-hydroxyimino-7- methyl-1,4,5,6,7,8-hexahydropyrrolo[2,3-c]azepin-8-one (15a, SUN9221) displayed potent alpha 1-adrenergic antagonistic activity (pA2 = 8.89 +/- 0.21) and 5-HT2 antagonistic activity (pA2 = 8.74 +/- 0.22) in isolated guinea pig arteries. This compound exhibited antihypertensive activity and a duration of action equivalent to orally administered prazosin or doxazosin, 3 mg/kg, in conscious spontaneously hypertensive rats, as well as potent antiplatelet aggregation activity.

P2-224 - Pharmacological studies of YM-35992. a novel selective 5-HT re-uptake inhibitor with 5-HT2 antagonistic activity

P2-224 - Pharmacological studies of YM-35992. a novel selective 5-HT re-uptake inhibitor with 5-HT2 antagonistic activity

Survey on the pharmacodynamics of the new antipsychotic risperidone

This review reports on the pharmacodynamics of the new antipsychotic risperidone. The primary action of risperidone is serotonin 5-HT2 receptor blockade as shown by displacement of radioligand binding (Ki: 0.16 nM), activity on isolated tissues (EC50: 0.5 nM), and antagonism of peripherally (ED50: 0.0011 mg/kg) and centrally (ED50: 0.014 mg/kg) acting 5-HT2 receptor agonists in rats. Risperidone is at least as potent as the specific 5-HT2 receptor antagonist ritanserin in these tests. Risperidone is also a potent dopamine D2 receptor antagonist as indicated by displacement of radioligand binding (Ki: 1.4 nM), activity in isolated striatal slices (IC50: 0.89 nM), and antagonism of peripherally (ED50: 0.0057 mg/kg in dogs) and centrally acting D2 receptor agonists (ED50: 0.056-0.15 mg/kg in rats). Risperidone shows all effects common to D2 antagonists, including enhancement of prolactin release. However, some central effects such as catalepsy and blockade of motor activity occur at high doses only. Risperidone is 4-10 times less potent than haloperidol as a central D2 antagonist in rats and it differs from haloperidol by the following characteristics: predominant 5-HT2 antagonism; LSD antagonism; effects on sleep; smooth dose-response curves for D2 antagonism; synergism of combined 5-HT2/D2 antagonism; pronounced effects on amphetamine-induced oxygen consumption; increased social interaction; and pronounced effects on dopamine (DA) turnover. Risperidone displays similar activity at pre- and postsynaptic D2 receptors and at D2 receptors from various rat brain regions. The binding affinity for D4 and D3 receptors is 5 and 9 times weaker, respectively, than for D2 receptors; interaction with D1 receptors occurs only at very high concentrations. The pharmacological profile of risperidone includes interaction with histamine H1 and alpha-adrenergic receptors but the compound is devoid of significant interaction with cholinergic and a variety of other types of receptors. Risperidone has excellent oral activity, a rapid onset, and a 24-h duration of action. Its major metabolite, 9-hydroxyrisperidone, closely mimics risperidone in pharmacodynamics. Risperidone can be characterized as a potent D2 antagonist with predominant 5HT2 antagonistic activity and optimal pharmacokinetic properties.

Pharmacological Effects of Zotepine and other Antipsychotics on the Central 5-HT2Receptors

The effects of the atypical neuroleptic zotepine in comparison with clozapine, risperidone and haloperidol were examined in tests related to the central 5-HT2 activity. Zotepine, as well as clozapine and risperidone, were very potent inhibitors of the 5-HTP-induced head twitches (the behavior mediated by 5-HT2 receptors) in mice, with rank order of potency risperidone > zotepine > clozapine; haloperidol used in high doses only slightly reduced the effect of 5-HTP. Zotepine, clozapine, risperidone and haloperidol antagonized the stimulatory effects of mCPP on the hind limb flexor reflex in spinal rats. As the mCPP-induced stimulation is considered to be mediated by 5-HT2 receptors, the above results provide further evidence for the 5-HT2 antagonistic activity of the drugs studied. Te rank order of potency in that test was the same as in the 5-HTP-induced head twitches (risperidone > zotepine > clozapine). The effect of haloperidol was somewhat unspecific, since its active doses were very high. In the model of hind limb flexor reflex of spinal rats, the anti-alpha 2-adrenergic effect was also tested. Clonidine-induced stimulation of the hind limb flexor reflex (an alpha 2-adrenergic effect) was antagonized by zotepine, clozapine, risperidone and haloperidol. It may be concluded that zotepine, clozapine and risperidone show an alpha 2-adrenergic antagonistic activity (order of potency: zotepine = risperidone > clozapine). The effect of haloperidol may be considered unspecific, since it is observed at high (cataleptic) doses only. In conclusion, it appears that zotepine, as well as clozapine and risperidone, are strong 5-HT2 antagonists, while haloperidol is not.

Syntheses of 5-HT2 antagonist activity of bicyclic 1,2,4-triazol-3(2H)-one and 1,3,5-triazine-2,4(3H)-dione derivatives

A series of bicyclic 1,2,4-triazol-3(2H)-one and 1,3,5-triazine-2,4(3H)-dione derivatives with a 4-[bis(4-fluoro-phenyl)methylene]piperidine or 4-(4-fluorobenzoyl)piperidine group has been prepared and tested for 5-HT2 and alpha 1 receptor antagonist activity. Among the compounds prepared, 2-[2-[4-[bis(4-fluorophenyl)methylene]-piperidin-1-yl]ethyl]- 5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyridin-3(2H)-one (7b) had the most potent 5-HT2 antagonist activity, which was greater than ritanserin (2), while 7b did not show alpha 1 antagonist activity in vivo. The central 5-HT2 receptor antagonism was approximately 1/30 that of 2 when tested for the ability to block head twitches induced by 5-hydroxytryptophan. Compound 21b, 3-[2-[4-(4-fluorobenzoyl)piperidin-1-yl]ethyl]-6,7,8,9-tetrahydro- 2H- pyrido[1,2-a]-1,3,5-triazine-2,4(3H)-dione also displayed potent 5-HT2 antagonist activity. The compound had moderate alpha 1 receptor antagonism, and the potency inhibiting head twitches was about one-third that of ketanserin (1). These results indicate that 5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyrimidin-3(2H)-one and 6,7,8,9-tetrahydro-2H-pyrido-[1,2-a]-1,3,5-triazine-2,4(3H)-dione ring systems are useful components of 5-HT2 antagonists.