Description

Technical Parameters

Introduction

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product-1400-1400

Products Description

## 1. Overview

Lidocaine, chemically known as 2-diethylamino-N-(2,6-dimethylphenyl)acetamide, is an aminoamide local anesthetic and antiarrhythmic drug. Since its first synthesis in 1943, it has become one of the most widely used local anesthetics in clinical practice. Its CAS number is **137-58-6**, molecular formula C₁₄H₂₂N₂O, and molecular weight is 234.34 g/mol. This article will systematically analyze lidocaine API from multiple dimensions, including classification, chemical properties, production process, application fields, and quality standards.

## 2. Classification system: segmentation based on purity and use

Lidocaine APIs can be divided into the following three categories based on purity, production process and end use:

### 1. Pharmaceutical Grade Lidocaine

- **CAS number**: 137-58-6

- **Purity standard**: ≥99.5% (HPLC)

- **Key indicators**: Meet the standards of the United States Pharmacopoeia (USP), European Pharmacopoeia (EP) or Chinese Pharmacopoeia (ChP), strictly control impurities (such as 2,6-dimethylaniline residue <0.1%), heavy metals (<10 ppm) and microbial limits.

- **Advantages**:

- High bioavailability, suitable for injections, patches, creams and other preparations.

- Strict aseptic process control to ensure clinical safety.

- High batch-to-batch consistency, meeting GMP production requirements.

- **Application scenarios**:

- Local anesthesia (such as surgery, dentistry, dermatology).

- Antiarrhythmic (intravenous injection).

- Analgesic patch (for neuropathic pain).

### 2. Industrial Grade Lidocaine

- **CAS number**: 137-58-6

- **Purity standard**: 95%-99%

- **Key indicators**: Focus on physical and chemical stability, with low requirements for microbial limits and specific impurities.

- **Advantages**:

- Cost-effective, suitable for non-invasive products.

- Customizable particle size (such as micronization).

- **Application scenarios**:

- External analgesic devices (such as electrode gel).

- Cosmetic additives (soothing ingredients).

- Veterinary anesthetic preparations.

### 3. Experimental Grade Lidocaine (Research Grade)

- **CAS Number**: 137-58-6

- **Purity Standard**: ≥99.9% (Mass Spectrometry Grade)

- **Key Indicators**: Ultra-low trace impurities (HPLC-MS verification), isotope labeling (such as ¹³C/¹⁵N labeling) optional.

- **Advantages**:

- Suitable for molecular mechanism research (such as sodium ion channel action analysis).

- Support pharmacokinetic (PK/PD) model development.

- **Application Scenarios**:

- Neuroscience laboratory (electrophysiological research).

- New dosage form development (nanocarrier delivery system).

- Toxicology research (metabolic pathway analysis).

## 3. Chemical and physical properties

### 1. Physical and chemical properties

- **Appearance**: White crystalline powder, odorless, slightly bitter.

- **Solubility**: easily soluble in ethanol (1:1.5), chloroform (1:40), slightly soluble in water (1:70,000).

- **Melting point**: 68-69℃.

- **pKa value**: 7.9 (25℃), which makes it partially ionized at physiological pH, which is conducive to penetrating cell membranes.

### 2. Synthesis process

The mainstream synthesis route uses 2,6-dimethylaniline as the starting material:

1. **Acylation reaction**: Condensation with chloroacetyl chloride to form 2-chloro-N-(2,6-dimethylphenyl)acetamide.

2. **Amination reaction**: Replace chlorine atoms with diethylamine under alkaline conditions to produce crude lidocaine.

3. **Refining**: Recrystallization (ethanol/water system) or column chromatography purification.

## 4. Pharmacological mechanism and clinical application

### 1. Mechanism of action

- **Sodium channel blockade**: reversibly inhibits voltage-gated sodium channels (VGSCs) and blocks nerve impulse conduction.

- **Membrane stabilization effect**: reduces the autonomy of cardiomyocytes and prolongs the effective refractory period (anti-arrhythmic effect).

### 2. Core indications

- **Local anesthesia**: infiltration anesthesia (0.5-1%), surface anesthesia (2-4%).

- **Arrhythmia**: ventricular tachycardia (1-3 mg/kg intravenous injection).

- **Pain management**: postherpetic neuralgia (transdermal patch 5%).

## 5. Quality and safety control

### 1. Key quality parameters

| Test items | Pharmaceutical grade standard (USP) | Industrial grade standard |

|----------------|-------------------|----------------|

| Purity (HPLC) | ≥99.5% | ≥95% |

| Moisture (KF method) | ≤0.5% | ≤1.0% |

| Residual solvent (GC) | Comply with ICH Q3C | No clear restrictions |

| Bacterial endotoxin | ＜0.1 EU/mg | Not tested |

### 2. Safety and storage

- **Toxicity data**: Rat oral LD₅₀=459 mg/kg, avoid inhalation or contact with mucous membranes.

- **Stability**: Store in a sealed container away from light (2-8℃), valid for 3 years.

- **Transportation specifications**: UN3249 (drugs, dangerous goods in item 6.1).

## 6. Market and regulatory trends

- **Major global suppliers**: Pfizer, Aspen Pharmacare, Jiangsu Hengrui Medicine, etc.

- **Patent status**: The patent for the core compound has expired, but new dosage forms (such as liposomes) are still protected.

- **Regulatory trends**: FDA strengthens the cardiotoxicity warning of local anesthetics, and the EU promotes green solvent technology.

## 7. Future research directions

1. **Targeted delivery system**: Develop pH-sensitive nanoparticles to reduce systemic exposure.

2. **Combined preparations**: Combined with epinephrine to extend the duration of anesthesia (1:100,000 ratio).

3. **Treatment of neurological diseases**: Exploring the neuromodulatory effects in epilepsy and chronic pain.

## Conclusion

The multidimensional classification system of lidocaine API reflects its full-chain value from basic research to industrial production. With the development of precision medicine, the development of high-purity and functionalized derivatives will further expand its application boundaries. Continuous optimization of synthesis process and quality control is the key to ensuring its clinical efficacy and safety.