1. Product Overview
Succimer (CAS: 304-55-2), also known as meso-2,3-Dimercaptosuccinic acid (DMSA), is a water-soluble organosulfur compound and a first-line oral chelating agent used globally for the treatment of heavy metal poisoning. Approved by the FDA in 1991 under the brand name Chemet®, Succimer is recognized in major pharmacopoeias (USP, EP, JP) and is the standard of care for pediatric and adult lead poisoning, as well as mercury and arsenic intoxication.
Succimer’s unique mechanism lies in its two adjacent sulfhydryl (-SH) groups, which form stable, water-soluble complexes with toxic heavy metal ions—particularly lead (Pb²⁺), mercury (Hg²⁺), and arsenic (As³⁺)—facilitating their renal excretion. Unlike older chelators such as BAL (dimercaprol) and EDTA, Succimer exhibits remarkable selectivity: it binds strongly to toxic metals while minimally depleting essential dietary minerals like zinc, copper, iron, and calcium. This selectivity, combined with its oral bioavailability and favorable safety profile with predominantly mild and transient side effects, makes it the preferred chelating agent in vulnerable populations including children.
Shaanxi TAIMA Bioengineering Co., Ltd. supplies high-purity Succimer (≥99% assay) manufactured under ISO 9001 and ISO 14001 certified facilities, with comprehensive documentation including COA, MSDS, TDS, and pharmacopoeial compliance data for every batch.
2. Physicochemical Properties
| Product Name | Succimer / 2,3-Dimercaptosuccinic Acid (DMSA) |
| CAS Number | 304-55-2 |
| EINECS | 206-155-2 |
| Molecular Formula | C₄H₆O₄S₂ |
| Molecular Weight | 182.22 g/mol |
| Appearance | White crystalline powder |
| Odor | Characteristic mercaptan (mild sulfur) odor |
| Solubility | Soluble in alkaline solutions; slightly soluble in methanol/ethanol; almost insoluble in water |
| Melting Point | 190.5–192.5°C |
| pH (1% solution) | 2.5–3.0 |
| Specifications | ≥99% by HPLC (typical: 99.3%) |
| Classification | Organosulfur compound; dithiol chelating agent |
| Pharmacopoeia | USP, EP, JP compliant |
3. Quality Specifications
| Test Item | Specification | Typical Result |
| Appearance | White crystalline powder | Complies |
| Assay (HPLC) | ≥ 99.0% | 99.3% |
| Melting Point | 190.5–192.5°C | 191.2°C |
| pH (1% solution) | 2.5–3.0 | 2.8 |
| Loss on Drying | ≤ 0.5% | 0.1% |
| Residue on Ignition | ≤ 0.1% | 0.05% |
| Heavy Metals | ≤ 10 ppm | < 10 ppm |
| Identification | Positive (IR/HPLC) | Complies |
4. Mechanism of Action
Succimer is a dithiol chelating agent containing two adjacent sulfhydryl (-SH) groups positioned on a succinic acid backbone. These thiol groups coordinate with divalent and trivalent heavy metal ions to form stable, water-soluble, five-membered chelate rings. The resulting complexes are efficiently eliminated from the body via renal excretion. Key mechanistic features include:
- High binding affinity for Pb²⁺, Hg²⁺, As³⁺, and Cd²⁺ ions through sulfur-metal coordination bonds
- Formation of hydrophilic chelate complexes that are readily excreted in urine, reducing metal body burden
- Critical selectivity advantage: minimal binding to essential divalent cations (Zn²⁺, Cu²⁺, Fe²⁺, Ca²⁺), preserving physiological mineral homeostasis
- Oral bioavailability of approximately 20%, achieving therapeutic blood levels within 1–2 hours post-dose
- Predominantly extracellular distribution, limiting CNS penetration and reducing neurotoxicity risk compared to BAL
- Does not redistribute lead to the brain (a known risk with EDTA), making it safer for treating lead encephalopathy
5. Key Benefits & Clinical Applications
Lead Poisoning (Plumbism): FDA-approved first-line oral therapy for pediatric and adult lead poisoning with blood lead levels ≥ 45 μg/dL. Clinically proven to reduce blood lead concentrations by 50–80% over a 5-day treatment course. Effectively chelates lead from soft tissues (liver, kidney, brain) while preserving essential mineral levels. Recommended by WHO and CDC guidelines.
Mercury Poisoning: Effective chelator for elemental, inorganic, and organic mercury intoxication. Used in dental amalgam-related mercury toxicity, occupational exposure, and environmental contamination cases. Crosses fewer biological membranes than DMPS, resulting in lower CNS penetration and a favorable safety profile for long-term oral administration.
Arsenic Detoxification: Forms stable complexes with trivalent arsenic (As³⁺), the most toxic arsenic species. Clinically used for acute and chronic arsenic poisoning including cases of groundwater contamination, industrial exposure, and intentional ingestion. Enhances urinary arsenic excretion by 3–5 fold compared to baseline.
Other Heavy Metal Intoxications: Demonstrates chelating activity against cadmium (Cd²⁺), antimony (Sb³⁺), and bismuth (Bi³⁺). Used off-label for polymetallic intoxication syndromes. Under investigation for thallium and tungsten poisoning.
Pediatric Safety Profile: Specifically approved for children as young as 12 months. Adverse effects are generally mild and transient: gastrointestinal discomfort (nausea, vomiting, diarrhea) in 10–15% of patients, mild transient transaminase elevation in 6–10%, and occasional skin rashes. Severe adverse events are rare, making DMSA the chelator of choice in pediatrics.
Chelation Challenge Testing: Used as a diagnostic tool in provoked urine heavy metal testing to assess total body burden of toxic metals. Post-DMSA urinary metal excretion provides a more accurate assessment than baseline blood levels alone.
6. Applications
6.1 Pharmaceutical (API)
- Active Pharmaceutical Ingredient (API) for oral chelation therapy: Chemet® (Recordati) and generic equivalents
- Lead poisoning treatment — 10 mg/kg every 8 hours for 5 days (standard regimen)
- Mercury poisoning — 10–30 mg/kg/day in divided doses
- Arsenic detoxification — adjunctive therapy with supportive care
- Diagnostic chelation challenge testing for heavy metal burden assessment
- Investigated for Wilson’s disease (copper overload) as an alternative to penicillamine
6.2 Environmental & Industrial
- Wastewater treatment: Removal of heavy metal ions (Pb, Hg, Cd, As) from industrial effluents
- Soil remediation: In-situ chelation of heavy metal contaminants for environmental cleanup
- Analytical chemistry: Chelating reagent for metal ion detection and quantification
7. TAIMA Competitive Advantages
High Purity: ≥99% HPLC with typical assay of 99.3%. Pharmacopoeia-compliant (USP, EP, JP).
GMP Manufacturing: ISO 9001:2015, ISO 14001:2015 certified facilities. Full Quality Management System.
Complete Documentation: COA, MSDS, TDS, stability data, residual solvent analysis, heavy metal testing, and pharmacopoeial compliance certificates.
Certifications: KOSHER, HALAL certified. DMF (Drug Master File) support available for regulatory filings.
Global Supply: Serving 50+ countries. Flexible packaging from 100 g R&D samples to 25 kg production drums.
Technical Support: Regulatory guidance, formulation support, analytical method transfer, and impurity profiling.
8. Packaging & Storage
| Standard Packaging | 25 kg/fiber drum or carton, double PE liner bags inside |
| Small Packaging | 1 kg/aluminum can; 100 g, 500 g aluminum foil sealed bags |
| Storage Temperature | 15–25°C (room temperature) |
| Storage Conditions | Store in a cool, dry place; protect from light; keep container tightly closed |
| Stability Note | Gradually oxidizes in air — minimize exposure to atmosphere during handling |
| Shelf Life | 24 months (unopened, stored under recommended conditions) |
