Chemical Information
- English Name: Paliperidone Palmitate
- Chemical Name: Hexadecanoic acid (1-[(2S,3S)-3-[2-[2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-piperidin-1-yl]ethyl]-6,7,8,9-tetrahydro-2H-pyrido[1,2-a]pyrimidin-4-yl]-2-methyl-1-oxidopropyl] ester
- Molecular Formula: C39H57FN4O4
- Molecular Weight: 664.89 g/mol
- CAS Number: 199739-10-1

Pharmacological Action:
Paliperidone palmitate is an atypical antipsychotic used primarily for the treatment of schizophrenia and schizoaffective disorder. It is a long-acting injectable form of paliperidone, the primary active metabolite of risperidone.

1.     Dopamine D2 Receptor Antagonism:

o    Paliperidone palmitate exerts its antipsychotic effect primarily through the blockade of D2 dopamine receptors in the brain. This reduces positive symptoms of schizophrenia such as delusions and hallucinations.

2.     Serotonin 5-HT2A Receptor Antagonism:

o    In addition to its effects on dopamine receptors, paliperidone palmitate also blocks 5-HT2A serotonin receptors, which helps improve negative symptoms and cognitive dysfunctions associated with schizophrenia.

3.     Antagonism of Other Receptors:

o    The drug also acts on other neurotransmitter receptors such as α1 and α2 adrenergic receptors and H1 histaminergic receptors, which contribute to its efficacy and side effect profile.

4.     Depot Formulation and Pharmacokinetics:

o    As a palmitate ester, paliperidone palmitate is formulated as a long-acting injectable that provides sustained delivery of paliperidone over a month or longer. This depot formulation ensures steady plasma levels, thereby reducing the risk of relapse due to non-compliance with oral medications.

o    Administered via intramuscular injection, it releases paliperidone over time as the ester is slowly hydrolyzed.