Niclosamide is a synthetic salicylanilide anthelmintic active pharmaceutical ingredient (API) used primarily for the treatment of tapeworm infections (cestode infections). It is a well-established antiparasitic compound and belongs to the salicylanilide class of anthelmintic agents.
Niclosamide has a distinctive chemical structure containing dichloro and nitro substituents on a salicylanilide backbone. It has also been extensively investigated in pharmacological and biomedical research for activities beyond its established anthelmintic application. PubChem identifies Niclosamide as an antiparasitic and anthelmintic drug and confirms its chemical identity and molecular properties.
Niclosamide is a specialized antiparasitic pharmaceutical API used in pharmaceutical formulation development, analytical research and manufacture of medicines for susceptible tapeworm infections.
For pharmaceutical-grade Niclosamide, important quality attributes include:
A current BP-listed technical specification for anhydrous Niclosamide provides numerical limits for assay, loss on drying, sulfated ash and specified impurities.
Product Name: Niclosamide
Synonyms: Niclosamide; 2′,5-Dichloro-4′-nitrosalicylanilide; 5-Chloro-N-(2-chloro-4-nitrophenyl)-2-hydroxybenzamide
CAS Number: 50-65-7
Molecular Formula: C13H8Cl2N2O4
Molecular Weight: 327.12 g/mol
IUPAC Name: 5-Chloro-N-(2-chloro-4-nitrophenyl)-2-hydroxybenzamide
Drug Class: Salicylanilide Anthelmintic
Therapeutic Class: Anthelmintic / Antiparasitic
Therapeutic Area: Infectious Diseases / Parasitology
Molecule Type: Synthetic Small Molecule
PubChem confirms the CAS number 50-65-7, molecular formula C13H8Cl2N2O4, and molecular weight 327.12 g/mol.
Niclosamide acts against susceptible helminths primarily by interfering with energy metabolism within the parasite.
Its established anthelmintic activity is associated with:
This mechanism contributes to its activity against tapeworms.
Niclosamide API is relevant to:
Niclosamide is an established oral anthelmintic used against tapeworm infections. PubChem identifies its approved drug use as treatment for tapeworm infections.
Its activity has historically included susceptible cestode infections such as:
The specific approved indications and dosing requirements depend on the applicable country's regulatory labeling.
Niclosamide belongs to the salicylanilide family of antiparasitic compounds.
Its chemical properties allow it to interfere with parasite energy metabolism, making it particularly useful against susceptible intestinal cestodes.
The compound has also been investigated extensively in laboratory research for additional biological activities, including pathways associated with cellular signaling and metabolism. These research findings should not be represented as established therapeutic indications unless supported by regulatory approval.
Niclosamide is an anhydrous crystalline pharmaceutical substance. The British Pharmacopoeia specification identifies anhydrous Niclosamide and gives a melting point range of 227–232°C.
It is described as:
These solubility characteristics are reported in the BP material.
Niclosamide can exist in different solid-state forms. Niclosamide monohydrate is a distinct hydrate with CAS Number 73360-56-2, molecular formula C13H10Cl2N2O5, and molecular weight 345.13 g/mol.
Therefore, an API page specifically describing anhydrous Niclosamide should not use the molecular weight or formula of Niclosamide monohydrate.
A controlled Niclosamide API manufacturing process may involve:
The exact commercial synthesis route should be based on the manufacturer's validated process and regulatory documentation.
Typical Niclosamide API testing may include:
The BP specification provides specific controls for 2-chloro-4-nitroaniline, 5-chlorosalicylic acid, related substances, loss on drying and sulfated ash.
For anhydrous Niclosamide BP, a current technical specification reports an assay requirement of 98.0%–101.0% on the dried basis.
This is preferable to using a generic 98–102% assumption because the value is tied to an identified BP specification.
Related substances are controlled using chromatographic testing.
A current BP technical specification reports:
Related substances: NMT 0.2%
It also provides specific limits for process-related impurities:
These values are reported for the referenced Niclosamide, Anhydrous, BP specification.
The referenced BP specification gives:
Loss on Drying: NMT 0.5%
This is particularly relevant for anhydrous Niclosamide because moisture and solid-state form can affect the characterization of the API.
The referenced BP specification gives:
Sulfated Ash: NMT 0.1%
This provides a numerical control for inorganic residue in the specified material.
The BP identification requirement gives:
Melting Point: 227–232°C
This can be used as a verified identification/characterization value for the specified anhydrous material rather than merely presenting it as an assumed physical property.
Niclosamide API should be stored in a tightly closed container under appropriate pharmaceutical storage conditions, protected from excessive moisture, heat and unsuitable environmental exposure.
The final storage conditions should be established according to the manufacturer's validated stability data and approved API specification.
| Parameter | Specification |
|---|---|
| Appearance | White crystalline powder or crystals |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 101.0% |
| Loss on Drying | NMT 0.5% |
| Residue on Ignition | NMT 0.1% |
| Water Content | NMT 0.5% |
| Melting Point | 227–232°C |