Aripiprazole

Aripiprazole is a new kind of highly lipid soluble quinoline derivatives, its pharmacological effects characteristic is that it is not only the postsynaptic dopamine D 2 receptor antagonist, but also the presynaptic dopamine D 2 receptor agonist,it can also excite D 1, D 3, D 4 receptors ; it has dual effect of partial activation or receptor antagonistic on 5-HT 1A receptor ; it has a completely antagonistic action on the 5-HT 2A receptor. This feature is different from the first generation, and atypical antipsychotics which belong to the second-generation antipsychotic drugs, and therefore it is called dopamine system stabilizer or third generation antipsychotic. Since it is sold in the market, it is mainly used in clinical schizophrenia, treatment of affective disorders and other psychiatric disorders. According to the literature, aripiprazole has significant effects on schizophrenia positive and negative symptoms and anxiety, depression, cognitive function , while higher safety. It was also reported that the drug can also treat other mental disorders, such as mood disorders manic episodes, senile dementia associated with mental disorders, anxiety disorders, children's behavioral disorders, depression.

Nowadays,Bristol-Myers Squibb and Otsuka Pharmaceutical Company announced that the European Union has approved Abilify (aripiprazole) in the treatment of schizophrenia listing application.
Schizophrenia affects 1% of the global population, and more in young adults. Schizophrenia affects thinking, emotional control and decision-making ability of the patient. Schizophrenia-positive patients will have symptoms such as hallucinations and delusions, patients with negative symptoms are social withdrawal, lack of emotional changes.
In 2002 the FDA approved Abilify for the treatment of schizophrenia, which has five dosage strengths: 5 mg, 10 mg, 15 mg, 20 mg and 30 mg, since its approval, in the United States ,a 1.8 million Abilify prescriptions have opened. aripiprazole approved by The EU has four sizes: 5 mg, 10 mg, 15mg and 30 mg.
Aripiprazole as an kind of antipsychotic drugs, in rare cases it may be associated with life-threatening neuroleptic malignant syndrome induced (NMS), also be associated with tardive dyskinesia (TD) have some relevance. Studies have shown that atypical antipsychotics may lead to hyperglycemia, although the study did not examine aripiprazole, but the relationship between hyperglycemia and aripiprazole remains uncertain, therefore, patients in treatment should be carried out blood glucose monitoring.
Patients before receiving aripiprazole treatment should be inform the doctor the physical condition and current drug situation . Aripiprazole should be used with caution in patients with a history of epilepsy aripiprazole.
In short-term clinical studies, the most common adverse reactions of aripiprazole compared with placebo groups are: headache (32%: 25%), anxiety (25%: 24%), insomnia (24%: 19%), nausea (14%: 10%), vomiting (12%: 7%), somnolence (11%: 8%), lightheadedness (11%: 7%), restlessness (10%: 7%) and constipation (10% :8%). A double-blind 26-week clinical study showed that there was higher incidence of tremor in aripiprazole group , it is 9%, only 1% while in the placebo group, slight tremor but tolerable , but also often led to discontinuation.

Metabolic pathway of aripiprazole is mainly through three kinds of biotransformation: dehydrogenation, hydroxylation and N-dealkylation. In vitro studies have shown, CYP3A4 and CYP2D6 are the two enzymes of the metabolism of the product , CYP3A4 and CYP2D6 are responsible for dehydrogenation and hydroxylation, and N-dealkylation is caused by CYP3A4 catalysis. Thus, when there is presence affecting two enzymatic activities and number of drugs, the amount of aripiprazole should be adjusted . In the steady state, pharmacokinetics of the product is proportional to dose. Single oral dose of 14C-labeled product showed that 55% of metabolites excreted through the feces, 25% excreted in urine and 18% of the original drug from the feces, 1% of the original drug excreted in the urine.
The above information is edited by the chemicalbook of Tian Ye.

Long-term toxicity: long-term toxicity study at a dose of 60 mg/kg for 26 weeks and 2-year carcinogenicity study at dose of 40 and 60mg/kg showed that this product caused retinal degeneration in rats. It showed no evidence of retinal degeneration in mice and monkey trials. Its mechanism of action has not been further researched, it is not shown that these findings is associated with human risks .
Carcinogenicity: In female mice, the daily 3~30mg/kg dose (based on surface area, respectively, is 0.5 to 5 times the MRHD; calculated by AUC, respectively, MRHD plasma concentrations of 0.1 to 0.9 times) leads to increasing incidence of pituitary tumors, breast cancer and skin cancer adenoacanthoma ; in female rats, the daily 10mg/kg dose (based on surface area is 3 times the MRHD; calculated by AUC, is MRHD plasma concentrations 0.1 times) causes increasing incidence of breast fibrous tumor ,daily 60mg/kg dose (based on surface area, is 19 times the MRHD; calculated by AUC, is MRHD plasma concentrations 14 times) causes increasing incidence of adrenocortical cancer and adrenal tumors .
Mutagenicity: in vitro bacterial reverse mutation assay, in vitro bacterial DNA recovery test, mouse lymphoma cells in vitro gene mutation test, Chinese hamster lung cells in vitro chromosomal aberration test, in vivo micronucleus test in mice and rats Unscheduled DNA synthesis test mutagenicity of this product. As a result, there is a positive response in the mouse micronucleus test in vivo, however, the positive reaction is considered to be independent to the mechanism of human .

1.It should be used with caution in combination with drugs acting on the central nervous system and alcohol.
2. aripiprazole has possibility of enhancing the role of certain antihypertensive drugs.
3. CYP3A4 inducer will result in elevated aripiprazole clearance and lower blood concentration, CYP3A4 inhibitor azole) or CYP2D inhibitors can inhibit aripiprazole elimination, increase plasma concentration.

The most common adverse reactions during treatment are headache, anxiety and insomnia. Rare adverse reactions are child blood sugar, even hyperglycemia.

Antipsychotics

Aripiprazole was launched for the treatment of psychoses including schizophrenia and offers a novel mechanism of action as a partial D₂ receptor agonist. Aripiprazole can be synthesized in three steps beginning by the condensation of 7-hydroxy-1,2,3,4- tetrahydroquinolin-2-one with 1 ,Cdibromobutane followed by reaction with 1-(2,3- dichlorophenyl)piperazine. Aripiprazole is a significant D₂ agonist/antagonist, 5-HT₂ antagonist and 5-HT_1α agonist combined with minimal affinity for a,-adrenergic, H₁ and M₁ receptors. It has a low D4:D2 selectivity ratio and a D2:5-HT₂ affinity ratio that exceeds 15; resulting in different pharmacological characteristics compared to other atypical antipsychotics agents such as clozapine. In animal models, aripiprazole inhibits apomorphine-induced stereotypy without causing catalepsy and ptosis. Moreover, in contrast to classical antipsychotics that produce disabling movement disorders, aripiprazole does not cause an upregulation of D2 receptors or an increase in immediate early gene expression of e.g. the c-fos mRNA in the striatum. In patients with acute relapse of schizophrenia, treatment with aripiprazole provided significant improvement in both positive and negative syndrome scale (PANSS) total score in both short- and longterm evaluations. These results were comparable to those observed with haloperidol or risperidone; however, the early response rate was greater with aripiprazole. Aripiprazole was well tolerated with mild to moderate adverse events such as nausea, dizziness, somnolence and weight gain. The rates of extrapyramidal symptoms were lower than with haloperidol, prolactin levels increase has been uncommon and no significant Q-Tc interval prolongation was observed compared with placebo. Finally, studies suggested a minimal impact of aripiprazole administration on total cholesterol levels and on fasting blood sugar in contrast to other antipsychotics. Aripiprazole has a bioavailability of 87%, a t_max of 3-5 h and a half-life time of 48-68 h. Aripiprazole has been found to have linear kinetics and is mainly metabolized via the cytochrome systems CYP2D6 and CYP3A4. It has little effect on the blood levels of other medications; interaction with both lithium and divalproex sodium found minimal impact. Aripiprazole has also been studied in other psychiatric disorders, including bipolar disorders and has shown great efficacy.

Colourless Flake Crystalline Solid

Otsuka (Japan)

For the treatment of schizophrenia and related psychotic disorders.

cerebral vasodilator, antimotion

A selective dopamine D2-receptor antagonist with dopamine autoreceptor agonist activity. Antipsychotic.

A deuterated version of Aripiprazole, a selective dopamine D2-receptor antagonist with dopamine autoreceptor agonist activity. Please note that users have reported separation of this compound and aripiprazole under normal-phase and reverse-phase

ChEBI: Aripiprazole is an N-arylpiperazine that is piperazine substituted by a 4-[(2-oxo-1,2,3,4-tetrahydroquinolin-7-yl)oxy]butyl group at position 1 and by a 2,3-dichlorophenyl group at position 4. It is an antipsychotic drug used for the treatment of Schizophrenia, and other mood disorders. It has a role as a H1-receptor antagonist, a serotonergic agonist, a second generation antipsychotic and a drug metabolite. It is a quinolone, a N-arylpiperazine, a N-alkylpiperazine, a dichlorobenzene, an aromatic ether and a delta-lactam.

To a solution of 4.06 g of K2CO3 with 400 ml of water was added 40 g of 7- hydroxy-3,4-dihydrocarbostyril [1] and 158 g of 1,4-dibrombutane. The mixture was refluxed for 3 hours. Then it was extracted with dichloremethane, dried with anhydrous MgSO4, the solvent was removed by evaporation. The residue was purified by means of silica gel chromatography (eluent: dichloromethane) and recrystallized from n-hexane-ethanol to yield 50 g of 7- (4-bromobutoxy)-3,4-dihydrocarbostyril, mp 110.5°-110.0°C.
47 g of 7-(4-bromobutoxy)-3,4-dihydrocarbostyril, 35 g of NaJ in 600 ml of acetonitrile was refluxed for 30 minutes. To this suspension was added 40 g of 1-(2,3-dichlorophenyl)piperazine (it was prepareted from 2,3-chloroaniline and di(2-bromoethyl)amine [1]) and 33 ml of triethylamine. The mixture was refluxed for 3 hours. After removing of the solvent, the residue was dissolved in chloroform, washed with water and dried with anhydrous MgSO4. The solvent was removed by evaporation, and residue was recrystallized from ethanol twice to yield 57.1 g of 7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl]- butoxy}-3,4-dihydrocarbostyril. Melting point: 139.0°-139.5°C.

Abilify (Otsuka).

Antipsychotic

Aripiprazole, (7-[4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butoxy]-3,4-dihydro-2(1H)-quinolone,is an atypical antipsychotic that is available in tablets(Abilify), orally disintegrating tablets (Abilify Discmelt), anda 1-mg/mL oral solution. Unlike the other atypical antipsychotics,aripiprazole exhibits partial agonist activity at D₂, D₃,D₄, and 5-HT_1A receptors, and antagonist action at 5-HT_2A receptors.Although aripiprazole exhibits a low incidence ofEPS, the compound occupies about 95% of striatal D₂ receptorsat therapeutic doses. Additionally, aripiprazole does nothave a fast rate of dissociation from D₂ receptors. Althoughthe mechanism of action of this compound remains to be elucidated,the atypical profile for aripiprazole may be related toits action at other monoamine receptors.The compoundis well absorbed with peak plasma levels occurring 3 to 5hours after oral administration. Food does not affect absorptionof aripiprazole. Aripiprazole is extensively metabolizedin the liver by the action of CYP2D6 and CYP3A4. The primarymetabolite in humans is dehydroaripiprazole. This metabolite represents about 40% of aripiprazoleat steady state.In the presence of CYP3A4 and CYP2D6 inhibitorsor inducers, dosage adjustments of aripiprazole maybe required. The mean elimination half-lives in extensive andpoor metabolizers are 75 hours and 146 hours, respectively.The major adverse effects of aripiprazole are headache, anxiety,and insomnia.Similar to other atypical antipsychotics,aripiprazole shows an increased risk in mortality in elderlypatients with dementia-related psychosis.Aripiprazoledemonstrates a different pharmacological profile from allother atypical antipsychotics.

Aripiprazole (Abilify). The newest, longactingaripiprazole (an arylpiperazine quinolinone derivative),appears to be partial agonist of D₂ receptors (i.e., itstimulates certain D2 receptors while blocking others dependingon their locations in the brain and the concentrationof drug). Bioavailability of aripiprazole is around 87%, with peak plasma concentration attained at 3 to 5 hours afterdosing. It is metabolized by dehydrogenation, oxidative hydroxylation, and N-dealkylation, largelymediated by hepatic CYPs 3A4 and 2D6.
The diphenylbutylpiperidine class can be considered amodification of the fluorobutyrophenone class. Because oftheir high lipophilicity, the compounds are inherently longacting. Pimozide has been approved for antipsychotic use,and penfluridol has undergone clinical trials in the UnitedStates. Overall, side effects for the two compounds resemblethose produced by the fluorobutyrophenones.

A poison.

Aripiprazole is a second generation atypical antipsychotic and anti-depressant with partial agonist activity at dopamine D2 and serotonin 5-HT1A receptors and antagonist activity at serotonin 5-HT2A receptors. Ki values are 0.34 nM, 0.8 nM, 1.7 nM, and 3.4 nM, respectively, for dopamine D2 and D3, serotonin 5-HT1A and 5-HT2A receptors. Aripiprazole is used in the treatment of schizophrenia.

Atypical antipsychotic:
Treatment of schizophrenia
Depression in bipolar disorder

A poison by intravenous route.When heated to decomposition it emits toxic vapors ofNOx and Cl^-.

Potentially hazardous interactions with other drugs
Anaesthetics: enhanced hypotensive effect.
Analgesics: increased risk of convulsions with tramadol; enhanced hypotensive and sedative effects with opioids; increased risk of ventricular arrhythmias with methadone.
Antihypertensives: may enhance antihypertensive effect.
Alcohol and other CNS drugs: increased sedation and other related side effects.
Anti-arrhythmics: increased risk of ventricular arrhythmias with anti-arrhythmics that prolong the QT interval.
Antibacterials: concentration possibly reduced by rifabutin and rifampicin - increase dose of aripiprazole.
Antidepressants: fluoxetine and paroxetine possibly inhibit metabolism - reduce dose of aripiprazole; concentration possibly reduced by St John’s wort - increase aripiprazole dose; increased concentration of tricyclics.
Antiepileptics: antagonises anticonvulsant effect; concentration reduced by carbamazepine and possibly reduced by fosphenytoin, phenytoin, phenobarbital and primidone - increase dose of aripiprazole.
Antifungals: metabolism inhibited by ketoconazole and possibly by itraconazole - reduce dose of aripiprazole.
Antimalarials: avoid with artemether/lumefantrine.
Antipsychotics: possible increased risk of ventricular arrhythmias with risperidone.
Antivirals: metabolism possibly inhibited by atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, ritonavir, saquinavir and tipranavir - reduce dose of aripiprazole; concentration possibly reduced by efavirenz and nevirapine - increase dose of aripiprazole.
Anxiolytics and hypnotics: increased sedative effects.
Atomoxetine: increased risk of ventricular arrhythmias.
Cytotoxics: increased risk of ventricular arrhythmias with arsenic trioxide.

Aripiprazole is extensively metabolised by the liver primarily by three biotransformation pathways: dehydrogenation, hydroxylation, and N-dealkylation. Based on in vitro studies, CYP3A4 and CYP2D6 enzymes are responsible for dehydrogenation and hydroxylation of aripiprazole, and N-dealkylation is catalysed by CYP3A4. Aripiprazole is the main active moiety in systemic circulation. At steady state, dehydroaripiprazole, the active metabolite, represents about 40% of aripiprazole AUC in plasma.
Following a single oral dose of [14C]-aripiprazole, approximately 27% of the administered radioactivity was recovered in the urine and approximately 60% in the faeces. Less than 1% of unchanged aripiprazole was excreted in the urine and approximately 18% was recovered unchanged in the faeces.

Store at -20°C

1) Green et al. (2004), Focus on aripiprazole; Curr. Med. Res. Opin., 20 207 2) Kikuchi et al. (1995), 7-(4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butyloxy)-3,4-dihydro-2(1H)-quinolinone (OPC-14597), a new putative antipsychotic drug with both presynaptic dopamine autoreceptor agonistic activity and postsynaptic D2 receptor antagonistic activity; J. Pharmacol. Exp. Ther., 274 329 3) Madhusoodanan et al. (2008), Management of psychosis in patients with Alzheimer’s disease: focus on aripiprazole; Clin. Interv. Aging, 3 491 4) Feltenstein et al. (2007), Aripiprazole blocks reinstatement of cocaine seeking in an animal model of relapse; Biol. Psychiatry, 61 582