Paliperidone Property

Melting point:

158-160°C

Boiling point:

612.3±65.0 °C(Predicted)

Density 

1.45±0.1 g/cm3(Predicted)

Flash point:

9℃

storage temp. 

2-8°C

solubility 

DMSO: soluble2mg/mL, clear (warmed)

pka

13.00±0.60(Predicted)

form 

powder

color 

white to brown

Stability:

Stable for 2 years from date of purchase as supplied. Solutions in DMSO may be stored at -20° for up to 2 months.

InChI

InChI=1S/C23H27FN4O3/c1-14-17(23(30)28-9-2-3-19(29)22(28)25-14)8-12-27-10-6-15(7-11-27)21-18-5-4-16(24)13-20(18)31-26-21/h4-5,13,15,19,29H,2-3,6-12H2,1H3

InChIKey

PMXMIIMHBWHSKN-UHFFFAOYSA-N

SMILES

C12C(O)CCCN1C(=O)C(CCN1CCC(C3C4=C(ON=3)C=C(F)C=C4)CC1)=C(C)N=2

CAS DataBase Reference

144598-75-4(CAS DataBase Reference)

Safety

Hazard Codes 

T,F

Risk Statements 

25-39/23/24/25-23/24/25-11

Safety Statements 

45-36/37-16

RIDADR 

UN 2811 6.1/PG 3

WGK Germany 

3

RTECS 

UV1164720

HazardClass 

6.1

PackingGroup 

III

HS Code 

29349990

Hazardous Substances Data

144598-75-4(Hazardous Substances Data)

Toxicity

rat,LD50,oral,65mg/kg (65mg/kg),Drug Development Research. Vol. 33, Pg. 399, 1994.

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H301Toxic if swalloed

Precautionary statements

P301+P310IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician.

Paliperidone Chemical Properties,Usage,Production

Description

Paliperidone, (±)-3-[2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]ethyl]-6,7,8,9-tetrahydro-9-hydroxy-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one(Invega), is essentially insoluble in water and is available asextended-release tablets. Paliperidone is delivered at a constantrate using an osmotic drug release device (OsmoticRelease Oral Systems [OROS]). Paliperidone is FDA-approved for schizophrenia aged 12–17. However, the pharmacologic portfolio, extrapolation from adult studies, and the long track record of the parent drug, risperidone in child/adolescent psychiatric (CAP) population might expand its therapeutic potential.

Metabolism

Paliperidone is the primary active metabolite of risperidone. The mechanism of action is unknown but it is likely to act via a similar pathway to risperidone. It has been proposed that the drug's therapeutic activity in schizophrenia is mediated through a combination of central dopamine Type 2 (D2) and serotonin Type 2 (5HT2A) receptor antagonism. Paliperidone is also active as an antagonist at alpha 1 and alpha 2 adrenergic receptors and H1 histaminergic receptors, which may explain some of the other effects of the drug. Paliperidone was approved by the FDA for treatment of schizophrenia on December 20, 2006.

Pharmacology

Paliperidone , 9-hydroxyrisperidone, is an atypical antipsychotic, a serotonin (5HT2A) dopamine (D2) antagonist and the active metabolite of the high-potency risperidone. It has also 5HT7 antagonism that might confer some antidepressant actions. It is advantageous given the osmotic-controlled release oral delivery system technique facilitating once-daily dosing, rapid steady-state, and hence better compliance. Moreover, lack of cytochrome CYP-450 enzyme interactions, more alpha-2 affinity, alleged less propensity for extrapyramidal syndromes, and availability of long-acting injection formulation all render paliperidone a very appealing treatment option in psychoses and in hepatic patients too.

Uses

This medication is used to treat certain mental/mood disorders (such as schizophrenia, schizoaffective disorder). This medication can decrease hallucinations and help you to think more clearly and positively about yourself, feel less agitated, and take a more active part in everyday life. Paliperidone belongs to a class of drugs called atypical antipsychotics. It works by helping to restore the balance of certain natural substances in the brain.

Mechanism of Action

Paliperidone is the major active metabolite of risperidone. The mechanism of action of paliperidone, as with other drugs having efficacy in schizophrenia, is unknown, but it has been proposed that the drug's therapeutic activity in schizophrenia is mediated through a combination of central dopamine Type 2 (D2) and serotonin Type 2 (5HT2A) receptor antagonism.

Description

Paliperidone, the C-9 hydroxylated active metabolite of the antipsychotic agent risperidone, is the newest atypical antipsychotic to join the market following the introductions of olanzapine (ZyprexaTM), risperidone (RisperdalTM), quetiapine(SeroquelTM), and ziprasidone (GeodonTM). Compared to its parent, paliperidone has improved PK properties and a reduced potential for drug interactions. In terms of receptor affinity, the two drugs are equipotent.

Chemical Properties

Off White to Light Orange Coloured Solid

Originator

Johnson & Johnson (US)

Uses

A metabolite of Risperidone, a combined serotonin (5-HT2) and dopamine (D2) receptor antagonist

Uses

Paliperidone(Invega) is an atypical antipsychotic. Chemically, paliperidone is the primary active metabolite of the older atypical antipsychotic risperidone. It is indicated for the acute and maintenance treatment of schizophrenia

Definition

ChEBI: 3-{2-[4-(6-fluoro-1,2-benzoxazol-3-yl)piperidin-1-yl]ethyl}-9-hydroxy-2-methyl-6,7,8,9-tetrahydropyrido[1,2-a]pyrimidin-4-one is a member of the class of pyridopyrimidines that is 9-hydroxy-2-methyl-6,7,8,9-tetrahydropyrido[1,2-a]pyrimidin-4-one carrying an additional 2-[4-(6-fluoro-1,2-benzoxazol-3-yl)piperidin-1-yl]ethyl group at position 2. It is a member of 1,2-benzoxazoles, a heteroarylpiperidine, an organofluorine compound, a pyridopyrimidine and a secondary alcohol.

brand name

Invega

General Description

Paliperidone, (±)-3-[2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]ethyl]-6,7,8,9-tetrahydro-9-hydroxy-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one(Invega), is essentially insoluble in water and is available asextended-release tablets. Paliperidone is delivered at a constantrate using an osmotic drug release device (OsmoticRelease Oral Systems [OROS]). The absolute bioavailabilityof paliperidone is 28%, and studies in healthy subjects on ahigh-fat, high-calorie meal showed an increase in AUC.Paliperidone is 74% bound to plasma proteins. After a single,1-mg dose of C-paliperidone, 59% of the dose was excretedin the urine as unchanged drug, and 32% of the dose was recoveredas metabolites. Most of the drug (80%) is excreted bythe kidneys. Paliperidone is metabolized by dealkylation, hydroxylation,dehydrogenation, and scission of the benzoxazolering. None of these metabolic pathways account for morethan 10% of the dose. The terminal elimination half-life ofpaliperidone is 23 hours.

Biochem/physiol Actions

Paliperidone is an atypical antipsychotic; active metabolite of risperidone.

Side effects

The most common adverse events included tachycardia, QTc prolongation, headache, anxiety, dizziness, tremors, and insomnia along with the dose-related events of somnolence, orthostatic hypotension, salivary hypersecretion, and extrapyrimidal disorder. Weight gain was also observed in 6–9% of patients which may be attributable to paliperidone’s lower affinity for H1-histaminergic and a1- and a2-adrenergic receptors. Patients with renal impairment require dose adjustments since elimination of paliperidone is altered. Paliperidone is contraindicated in patients with a hypersensitivity to risperidone. Concomitant use of class III antiarrhythmic agents should be avoided since this may result in additive QT interval prolongation. Also, loss of levodopa efficacy is expected with this D2 antagonist.

Synthesis

The synthesis of paliperidone involves the reaction of 2-acetyl-g-butyrolactone with 2-amino-3-benzyloxypyridine in the presence of phosphoryl chloride. The benzyl protecting group of the intermediate 9-benzyloxy- 3-(2-chloroethyl)-2-methylpyrido[1,2-a]pyrimidin-4-one is then removed by hydrogenolysis over Pd/C followed by the nucleophilic displacement of the chlorine with 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole to provide racemic paliperidone. While paliperidone can be resolved, both enantiomers are equipotent and interconvert in vivo obviating the need for separation.

Drug interactions

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.
Anti-arrhythmics: increased risk of ventricular arrhythmias when given with anti-arrhythmics that prolong the QT interval.
Antidepressants: increases concentration of tricyclics (possibly increased risk of ventricular arrhythmias).
Antiepileptics: antagonise anticonvulsant effect (convulsive threshold lowered); concentration reduced by carbamazepine.
Antimalarials: avoidance of antipsychotics advised by manufacturer of artemether/lumefantrine.
Antipsychotics: possible increased risk of ventricular arrhythmias with risperidone.
Antivirals: concentration possibly increased by ritonavir.
Atomoxetine: increased risk of ventricular arrhythmias with atomoxetine.
Cytotoxics: increased risk of ventricular arrhythmias with arsenic trioxide.

Metabolism

Paliperidone is the active metabolite of risperidone. Four metabolic pathways have been identified in vivo, none of which accounted for more than 6.5% of the dose: dealkylation, hydroxylation, dehydrogenation, and benzisoxazole scission.
Following administration of [14C]-paliperidone, 59% of the dose was excreted unchanged into urine, indicating that paliperidone is not extensively metabolised in the liver. Approximately 80% of the administered radioactivity was recovered in urine and 11% in the faeces.

storage

+4°C

References

1) Beijsterveldt?et al.?(1994),?Regional brain distribution of risperidone and its active metabolite 9-hydroxy-risperidone in the rat; Psychopharmacology,?114?53 DOI:10.1007/BF02245444
2) Leysen?et al. (1994),?Risperidone: a novel antipsychotic with balanced serotonin-dopamine antagonism, receptor occupancy profile, and pharmacologic activity; J. Clin. Psychiatry,?55?suppl: 5 PMID: 7520908
3) Schotte?et al.?(1996),?Risperidone compared with new and reference antipsychotic drugs: in vitro and in vivo receptor binding; Psychopharmacology (Berl.),?124?57 DOI:10.1007/BF02245606