Pitolisant is a pharmaceutical active ingredient used as a selective histamine H3 receptor antagonist/inverse agonist. The pharmaceutical product form is Pitolisant Hydrochloride, identified by CAS Number 903576-44-3, with molecular formula C₁₇H₂₇Cl₂NO and molecular weight 332.31 g/mol. Pitolisant is used in the treatment of excessive daytime sleepiness associated with narcolepsy.
Pitolisant API is a small-molecule histamine H3 receptor antagonist/inverse agonist. Pitolisant hydrochloride is the hydrochloride salt of the pitolisant active moiety and is the form used in the FDA-approved WAKIX tablets. FDA describes pitolisant hydrochloride as a white or almost white crystalline powder.
Pitolisant hydrochloride should be distinguished from the pitolisant free base. The free base has CAS Number 362665-56-3, molecular formula C₁₇H₂₆ClNO, and molecular weight 295.85 g/mol, whereas the hydrochloride has CAS 903576-44-3 and molecular weight 332.31 g/mol.
Pitolisant hydrochloride has the molecular formula C₁₇H₂₇Cl₂NO and molecular weight 332.31 g/mol. PubChem reports an exact mass of 331.1469699 Da, hydrogen-bond donor count of 1, hydrogen-bond acceptor count of 2, rotatable bond count of 8, and topological polar surface area of 12.5 Ų.
The chemical name is 1-[3-[3-(4-chlorophenyl)propoxy]propyl]piperidine hydrochloride. Pitolisant hydrochloride is a crystalline solid and is reported to be soluble in water, ethanol and methylene chloride, while being practically insoluble in cyclohexane.
Pitolisant is a centrally acting histamine H3 receptor antagonist/inverse agonist that increases histaminergic activity associated with wakefulness. FDA approved WAKIX for the treatment of excessive daytime sleepiness in adult patients with narcolepsy.
Pharmaceutical applications of Pitolisant API include:
Pitolisant hydrochloride can be evaluated using HPLC, LC-MS, NMR, chromatographic impurity testing, assay determination and other appropriate analytical techniques.
A Sigma-Aldrich reference product lists Pitolisant Hydrochloride at ≥98% by HPLC, with a powder form and white to beige color. The same reference material reports water solubility of 2 mg/mL and storage at 2–8°C under desiccated conditions. These values relate to that analytical/research product and should not automatically be treated as a universal pharmacopoeial API specification.
For commercial pharmaceutical API material, assay, related substances, residual solvents, water content, elemental impurities and other quality attributes should be controlled according to the applicable approved specification and batch-specific Certificate of Analysis.
Pitolisant Hydrochloride API is identified by CAS 903576-44-3, molecular formula C₁₇H₂₇Cl₂NO, and molecular weight 332.31 g/mol. The API is relevant to pharmaceutical manufacturing and development of medicines containing pitolisant hydrochloride.
Quality evaluation can include identity confirmation, HPLC assay, chromatographic purity, related-substance analysis, residual-solvent testing and other applicable pharmaceutical quality tests. Technical documentation can be provided according to the applicable grade and batch requirements.
Pitolisant Hydrochloride should be packaged in tightly closed, suitable pharmaceutical-grade containers that protect the material from moisture, contamination and unsuitable environmental exposure.
For a commercially available analytical-grade Pitolisant Hydrochloride reference material, storage at 2–8°C under desiccated conditions is reported. Commercial API storage should follow the approved product specification, packaging configuration and stability data applicable to the supplied material.
Applicable documentation may include:
Pitolisant Hydrochloride is a well-characterized pharmaceutical active ingredient with an established mechanism as a histamine H3 receptor antagonist/inverse agonist. Its CAS Number 903576-44-3, molecular formula C₁₇H₂₇Cl₂NO, and molecular weight 332.31 g/mol provide clear identification of the hydrochloride API form.
The availability of established analytical characterization data, including HPLC assay, identity testing and documented physical properties, supports pharmaceutical development and quality-control activities. The exact API specification should always be verified against the applicable batch Certificate of Analysis and approved quality requirements.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 0.5% |
| Residue on Ignition | NMT 0.1% |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 0.5% |