Phenylbutazone (BP, EP, USP)

Phenylbutazone (BP, EP, USP) Detailed Description

1. Chemical Identity

• Chemical Name: 4-Butyl-1,2-diphenyl-3,5-pyrazolidinedione

• Chemical Formula: C19H20N2O2

• Molecular Weight: 312.37 g/mol

• Structure: It is a pyrazolidinedione derivative with two phenyl groups and a butyl side chain.

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2. Physical Description

• Appearance: White or almost white crystalline powder or crystals.

• Solubility: Slightly soluble in water, soluble in alcohol, chloroform, and ether.

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3. Pharmacopoeial Standards

a. British Pharmacopoeia (BP)

• Identification Tests: IR spectrum, UV spectrum, and specific chemical reactions confirm identity.

• Assay: Typically uses titration or chromatographic methods (HPLC) to determine purity and content. Should contain not less than 98.0% and not more than 102.0% of C19H20N2O2.

• Related Substances: Limits on impurities and degradation products defined. Uses chromatography (e.g., HPLC) for quantification.

• Loss on Drying: Usually less than 0.5%, ensuring minimal moisture content.

• Residue on Ignition: Usually less than 0.1%.

• Heavy Metals: Controlled to a defined low limit.

• Microbial Limits: Specified to ensure product safety.

b. European Pharmacopoeia (EP)

• Similar to BP in identification methods and purity requirements.

• Assay: May specify HPLC method with defined mobile phase, column type, and detection wavelength.

• Impurities: Lists specific known impurities with maximum allowable limits.

• Physical Properties: Melting point usually ranges from 97 C to 103 C.

• Other Tests: Tests for heavy metals, residual solvents, and microbial contamination.

c. United States Pharmacopeia (USP)

• Identification: IR spectrum, UV absorbance, and chromatographic profile.

• Assay: Typically by HPLC or titration. Assay range usually between 98.0% and 102.0%.

• Impurities: Limits on known impurities and degradation products.

• Physical Properties: White crystalline powder, melting point around 97-103 C.

• Microbial Limits: USP sets limits for non-sterile products.

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4. Pharmacological Properties

• Phenylbutazone is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic and antipyretic properties.

• It works by inhibiting cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis.

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5. Storage and Handling

• Store in a well-closed container, protected from light and moisture.

• Stable under normal conditions but sensitive to prolonged exposure to air and light.

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6. Usage

• Historically used to treat inflammatory conditions such as arthritis and gout.

• Due to side effects, its use in humans has declined but it is still used in veterinary medicine.