Pancuronium Bromide API is a synthetic, long-acting non-depolarizing neuromuscular blocking agent belonging to the aminosteroid class of muscle relaxants. It is the dibromide salt of pancuronium and acts primarily at the neuromuscular junction by competitively antagonizing nicotinic acetylcholine receptors. This prevents acetylcholine from activating skeletal-muscle motor endplates and produces reversible skeletal muscle relaxation.
Pancuronium Bromide has the CAS Number 15500-66-0, molecular formula C₃₅H₆₀Br₂N₂O₄, and molecular weight approximately 732.7 g/mol. FDA GSRS and PubChem identify Pancuronium Bromide as the bromide salt of the pancuronium dication.
Pancuronium Bromide is reported as a white, yellowish-white or slightly pink crystalline, hygroscopic powder in pharmacopoeial information. It is very soluble or freely soluble in water, very soluble in methylene chloride and freely soluble in ethanol (96%).
Pancuronium belongs to the non-depolarizing neuromuscular blocking agent class. It produces skeletal-muscle paralysis through competitive blockade of nicotinic acetylcholine receptors at the neuromuscular junction. Unlike depolarizing neuromuscular blockers, it does not produce persistent depolarization of the motor endplate.
Pancuronium competitively binds to nicotinic acetylcholine receptors at the neuromuscular junction. By preventing acetylcholine from binding effectively, it inhibits transmission of nerve impulses from motor nerves to skeletal muscle. The resulting neuromuscular blockade produces muscle relaxation and paralysis.
Pancuronium Bromide has been used as a neuromuscular blocking agent in anesthetic practice to provide skeletal-muscle relaxation during surgical and other controlled medical procedures. Because neuromuscular blockade can affect respiratory muscles, pharmaceutical formulations containing pancuronium are intended for use under appropriate medical supervision with facilities for airway and respiratory support.
The substance is pharmacologically distinct from the parent pancuronium cation. For API identification and specification purposes, the bromide salt CAS 15500-66-0 should be used when the product is Pancuronium Bromide.
Pancuronium Bromide has an established pharmacopoeial identity and assay framework. The USP monograph specifies 98.0–102.0% Pancuronium Bromide calculated on the anhydrous basis. USP identification includes infrared spectroscopy, chromatographic retention-time comparison and a bromide identification test.
The USP assay uses liquid chromatography with conductivity detection and suppression. The monograph specifies a system-suitability requirement of NMT 2.0 for tailing factor and NMT 1.0% relative standard deviation.
BP/Ph. Eur. information similarly specifies 98.0–102.0% on anhydrous substance and describes Pancuronium Bromide as a hygroscopic crystalline powder with high aqueous solubility.
Pancuronium Bromide has multiple defined stereogenic centers associated with its steroidal structure. PubChem identifies 10 defined atom stereocenters and no undefined atom stereocenters. Consequently, stereochemical identity is an important part of pharmaceutical API characterization.
Typical Pancuronium Bromide API documentation may include:
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.2% |
| Heavy Metals | NMT 10 ppm |
| Individual Impurity | NMT 0.5% |
| Specific Rotation | +39.0° to +43.0° (c = 3, water; calculated on anhydrous substance) |
| Melting Point | 150°C – 154°C |