Pranlukast API is a cysteinyl leukotriene receptor-1 (CysLT1) antagonist used in the management of respiratory allergic conditions. The pharmacopoeial pharmaceutical form is Pranlukast Hydrate, chemically represented as C27H23N5O4·½H2O, with a molecular weight of 490.51 g/mol and CAS Number 150821-03-7. The anhydrous Pranlukast active moiety has CAS 103177-37-3 and molecular weight 481.50 g/mol.
The Japanese Pharmacopoeia describes Pranlukast Hydrate as a white to light yellow crystalline powder, very slightly soluble in ethanol (99.5) and practically insoluble in water. Its pharmacopoeial assay is 98.0% to 101.0% of Pranlukast on an anhydrous basis.
Pranlukast is a leukotriene receptor antagonist belonging to the chromone class. It acts by antagonizing cysteinyl leukotriene receptors involved in bronchoconstriction and allergic inflammatory responses. PubChem identifies the anhydrous compound as C27H23N5O4, CAS 103177-37-3, with a molecular weight of 481.5 g/mol.
For pharmaceutical API specifications, the hydrate form is particularly important. The Japanese Pharmacopoeia identifies the API as Pranlukast Hydrate, formula C27H23N5O4·½H2O, molecular weight 490.51, CAS 150821-03-7.
| Parameter | Value |
|---|---|
| Product Name | Pranlukast |
| Pharmacopoeial Form | Pranlukast Hydrate |
| CAS Number | 150821-03-7 |
| Alternate / Anhydrous CAS | 103177-37-3 |
| Molecular Formula | C27H23N5O4·½H2O |
| Molecular Weight | 490.51 g/mol |
| Anhydrous Molecular Weight | 481.50 g/mol |
| UNII | FR702N558K |
| ChEBI | CHEBI:94810 |
| DrugBank | DB01411 |
| Physical Form | Crystalline powder |
| Appearance | White to light yellow crystalline powder |
| Pharmacopoeial Standard | Japanese Pharmacopoeia (JP) |
Pranlukast is chemically identified as N-[4-oxo-2-(1H-tetrazol-5-yl)-4H-chromen-8-yl]-4-(4-phenylbutoxy)benzamide in the Japanese Pharmacopoeia monograph. The molecule contains a chromone ring, tetrazole group and substituted benzamide structure.
PubChem reports an XLogP3-AA value of 4.2, hydrogen-bond donor count of 2, hydrogen-bond acceptor count of 7, rotatable bond count of 9, and topological polar surface area of 119 Ų for the anhydrous molecule.
Pranlukast Hydrate has a reported melting/decomposition temperature of approximately 233°C in the Japanese Pharmacopoeia. Independent physicochemical research reports a melting range of 231–235°C for Pranlukast Hydrate.
The hydrate is highly water-insoluble. Published physicochemical research reports aqueous solubility of approximately 1.2 × 10⁻³ mg/mL at 25°C. The JP description classifies it as practically insoluble in water.
Pranlukast is a cysteinyl leukotriene receptor-1 antagonist. It inhibits the activity of leukotrienes that contribute to bronchoconstriction and allergic inflammatory responses.
The active pharmaceutical ingredient has been used in respiratory and allergic-condition formulations, including products intended for management of bronchial asthma and allergic rhinitis.
Pranlukast Hydrate has an established Japanese Pharmacopoeia monograph, making it possible to use verified pharmacopoeial numerical specifications rather than generic API limits.
The JP monograph specifies:
The JP assay is calculated against Pranlukast Reference Standard on an anhydrous basis and requires the API to contain 98.0–101.0% Pranlukast on that basis.
The official JP water specification is 1.5–2.2%, while residue on ignition is NMT 0.2%. Heavy metals are controlled at NMT 20 ppm, and arsenic at NMT 2 ppm.
For related substances, the JP method establishes quantitative relative limits through comparison with a diluted Pranlukast reference solution. These correspond approximately to NMT 0.50% for the specified impurity at relative retention time around 1.5, NMT 0.20% for each other individual impurity, and NMT 1.0% total related substances when expressed relative to the assay reference concentration. These percentages are calculated from the official JP dilution ratios rather than printed directly as percentage limits in the monograph.
Pranlukast API manufacturing requires controlled synthesis, purification and strict control of the hydrate form. Because the pharmacopoeial API is Pranlukast Hydrate, control of water content is an important part of batch quality.
Analytical controls should include HPLC assay, related-substance testing, IR/UV identification, water determination, residue on ignition, heavy-metal testing and arsenic determination in accordance with the applicable specification.
The Japanese Pharmacopoeia monograph provides a strong reference framework for manufacturing and analytical quality control of Pranlukast Hydrate.
Pranlukast Hydrate should be stored in tight containers and protected from conditions that could alter the hydrate state or compromise chemical quality.
Because the API contains approximately half a mole of water per mole of Pranlukast, control of moisture is particularly important. The JP monograph specifies a water content of 1.5–2.2% for Pranlukast Hydrate.
Commercial analytical material from TCI is listed for refrigerated storage at 0–10°C and is described as heat-sensitive.
Pranlukast API documentation can include:
Pranlukast is a well-characterized leukotriene receptor antagonist with an established pharmaceutical history and a defined pharmacopoeial specification for Pranlukast Hydrate.
Unlike APIs for which only commercial research specifications are publicly available, Pranlukast Hydrate has detailed Japanese Pharmacopoeia requirements covering assay, water, residue on ignition, heavy metals, arsenic and related substances. This allows more reliable numerical specifications to be presented for API quality information.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0–101.0% |
| Residue on Ignition | NMT 0.2% |
| Heavy Metals | NMT 20 ppm |
| Individual Impurity | NMT 0.50% |
| Total Impurities | NMT 1.0% |
| Water Content | 1.5–2.2% |
| Melting Point | About 233°C, with decomposition |