Quick Facts
| CAS Number | 51-05-8 |
|---|---|
| Molecular Formula | C13H20N2O2 · HCl |
| Molecular Weight | 272.77 |
| Pharmacopoeia | BP/EP/USP |
| Packaging | 25 KG/DRUM |
Product Overview
Procaine hydrochloride was synthesized in 1905 by the German chemist Alfred Einhorn at the Hoechst dye works — an origin story that connects directly to the broader history of pharmaceutical chemistry. Einhorn had been searching for a synthetic substitute for cocaine, which was then the only available local anesthetic but carried well-known toxicity and addiction risks. His breakthrough was the amino ester scaffold: a lipophilic aromatic ring (para-aminobenzoic acid) linked by an ester bond to a hydrophilic tertiary amine (diethylaminoethanol). Einhorn named his creation "Novocain" (from Latin novus = new + cocaine) and it was commercialized by Hoechst in 1905. For the next four decades, procaine was the dominant local anesthetic worldwide.
The class distinction between amino ester and amino amide local anesthetics is both chemically and clinically important. Procaine, as an ester, is hydrolyzed by plasma pseudocholinesterase to para-aminobenzoic acid (PABA) and diethylaminoethanol — both metabolites are pharmacologically inactive and rapidly excreted. This plasma-based metabolism means procaine has lower systemic toxicity than liver-metabolized amides like lidocaine, but it also means a shorter duration of action (30-60 minutes vs. 1-2 hours). The PABA metabolite is responsible for the rare allergic reactions associated with ester anesthetics, though the incidence is very low at less than 1%. This is the fundamental clinical trade-off: procaine is intrinsically safer from a toxicity standpoint but more likely to cause allergic sensitization than amide anesthetics.
The most important use of procaine by volume today is not as a standalone anesthetic — it is as the procaine component in procaine penicillin G. When procaine and penicillin G are combined in equimolar amounts, they form a poorly water-soluble salt (1:1 complex) with a solubility of approximately 4 mg/mL. Following intramuscular injection, the salt slowly dissociates, releasing penicillin G gradually over 12-24 hours for a prolonged depot effect. This extends the penicillin dosing interval from every 6 hours to once daily, which has enormous practical significance in veterinary medicine where handling animals for frequent injections is labor-intensive and stressful. Procaine penicillin G is one of the most widely used veterinary antibiotics worldwide.
As of mid-2026, procaine HCl maintains two distinct and stable global markets. The larger market by volume is procaine penicillin G API, driven by livestock antibiotic demand in Asia, Latin America and Africa. The smaller but higher-margin market is pharmaceutical-grade procaine for injectable anesthetic solutions and dental cartridges, primarily in Eastern Europe and parts of Asia where procaine has never been displaced by lidocaine. China dominates global procaine production, with manufacturing concentrated in Shandong and Zhejiang provinces. KingWish supplies GMP-certified procaine HCl meeting BP, EP and USP specifications for both the veterinary penicillin salt market and human pharmaceutical anesthetic formulations.
Quality Specifications
| Purity (Titration) | ≥ 99.0% (dried basis), per BP/EP/USP monograph |
|---|---|
| 4-Aminobenzoic Acid (PABA) | ≤ 0.05% (critical stability-indicating degradation product) |
| Melting Point | 154-158 deg C (BP/EP specification) |
| pH (2% Solution) | 5.0-6.5 |
| Residual Solvents | Compliant with ICH Q3C |
| Heavy Metals | ≤ 10 ppm |
| GMP Status | Manufactured under ICH Q7 GMP conditions |
Veterinary Applications
Local Anesthesia (2% Injection)
Infiltration and nerve block anesthesia for minor veterinary surgical procedures — wound suturing, skin biopsy, abscess drainage, dental extractions and castration. Onset 5-10 min, duration 30-60 min.
Procaine Penicillin G Formulations
Prolonged-release intramuscular penicillin for livestock and companion animals. Once-daily dosing replaces 4x daily sodium/potassium penicillin. The most important use of procaine by global volume.
Therapeutic Areas
- Veterinary local anesthesia: Infiltration anesthesia, nerve blocks, dental procedures, minor surgery in cattle, swine, horses and companion animals
- Procaine penicillin G: Prolonged-release depot antibiotic for bacterial infections in livestock — respiratory infections, wound infections, clostridial diseases
- Human dental anesthesia: 2% procaine with epinephrine for dental procedures in markets where procaine is the standard local anesthetic
- Minor surgical procedures: Wound suturing, skin biopsy, abscess drainage, laceration repair
Sourcing Procaine HCL: Key Checks
Documentation
Request CoA with titration assay, PABA content (the most important stability-indicating test), melting point, pH of 2% solution, residual solvent statement (ICH Q3C), heavy metals and GMP certificate. For procaine penicillin G manufacturers, also request particle size distribution data.
Red Flags
Elevated PABA above the 0.05% limit (indicates ester hydrolysis during storage or inadequate purification), low melting point (impurity), off-white or yellow discoloration, pH outside 5.0-6.5 range and missing PABA test entirely on the CoA.
Packaging & Logistics
Standard: 25 KG/DRUM with PE liner. Store at 15-30 deg C in airtight containers, protected from moisture. Procaine HCL is hygroscopic and sensitive to pH — both moisture and alkaline conditions accelerate ester hydrolysis to PABA. Standard lead time 4-6 weeks.
Market Context
Global procaine demand is driven primarily by procaine penicillin G manufacturing. While procaine has been replaced by lidocaine/articaine for most human surgery in Western markets, it retains strong positions in Eastern Europe Latin America and Asia. Procaine HCL is also a regulated precursor in some jurisdictions due to its structural relationship to controlled substances — verify local import requirements.