Mepyramine, also known as pyrilamine, is a first-generation H1 antihistamine used to reduce the effects of histamine in allergic conditions. It belongs to the ethylenediamine class of antihistamines and acts primarily by competitively blocking histamine H1 receptors.
Mepyramine has antihistaminic and anticholinergic properties and has been used in pharmaceutical preparations for the management of allergic symptoms, itching and histamine-mediated reactions.
Mepyramine has the molecular formula C17H23N3O and a molecular weight of approximately 285.39 g/mol. Its CAS Number is 91-84-9.
The compound is a synthetic ethylenediamine antihistamine and is commonly encountered as mepyramine maleate in pharmaceutical formulations.
Mepyramine acts as a competitive antagonist/inverse agonist at histamine H1 receptors. By reducing histamine activity at H1 receptors, it helps decrease histamine-mediated effects such as itching, redness, swelling and increased vascular permeability.
As a first-generation antihistamine, mepyramine can also produce sedative and anticholinergic effects because of its ability to cross the blood-brain barrier.
Mepyramine is used in pharmaceutical preparations associated with the treatment or relief of histamine-mediated allergic symptoms.
Applications include:
Approved uses and formulations vary according to the regulatory jurisdiction.
Mepyramine API can be evaluated using validated analytical procedures for identity, assay, related substances, water content, residual solvents, elemental impurities and other applicable quality attributes.
HPLC and spectroscopic techniques can be used for identity, assay and impurity determination. Where a specific salt form such as mepyramine maleate is manufactured, appropriate testing should confirm the identity and composition of the salt.
Final acceptance criteria should follow the applicable manufacturer's approved drug-substance specification and Certificate of Analysis.
Mepyramine should be stored in a tightly closed pharmaceutical-grade container under controlled conditions and protected from excessive heat, moisture and direct light.
Specific storage requirements should follow the manufacturer's approved specification.
Mepyramine API may be supplied for qualified pharmaceutical manufacturing, formulation development, analytical and research applications, subject to applicable quality and regulatory requirements.
Mepyramine API is available for qualified pharmaceutical development and manufacturing requirements. Customers can request product specifications, Certificate of Analysis, analytical documentation, packaging information and commercial details according to their requirements.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 2.0% |
| Residue on Ignition | NMT 1.0% |
| Heavy Metals | NMT 10 ppm |
| pH (1% Solution) | 5.0 – 8.0 |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 2.0% |
| Water Content | NMT 2.0% |
| Melting Point | Approximately 70–75 °C |