Aspirin DL-lysine
[CAS# 62952-06-1]

Identification

• Classification: API >> Antipyretic analgesics >> Antipyretic and analgesic
• Name: Aspirin DL-lysine
• Synonyms: DL-Lysine acetylsalicylate
• Molecular Formula: C₉H₈O₄^.C₆H₁₄N₂O₂;C₁₅H₂₂N₂O₆
• Molecular Weight: 326.35
• CAS Registry Number: 62952-06-1
• EC Number: 263-769-3
• SMILES: CC(=O)OC1=CC=CC=C1C(=O)O.C(CCN)CC(C(=O)O)N

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H302
• Precautionary Statements: P264-P270-P301+P317-P330-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302

Discovory and Applicatios

Aspirin DL-lysine is a salt formed by combining acetylsalicylic acid (aspirin) with DL-lysine, a racemic mixture of the amino acid lysine. This compound exists as a white to slightly yellowish crystalline powder, readily soluble in water, and was developed to enhance the solubility and gastrointestinal tolerability of aspirin for rapid therapeutic use, particularly in injectable and high-bioavailability formulations.

Aspirin itself is a well-known nonsteroidal anti-inflammatory drug (NSAID) discovered in the late 19th century and widely used for its analgesic, antipyretic, anti-inflammatory, and antiplatelet effects. Its therapeutic action is primarily through irreversible inhibition of cyclooxygenase (COX) enzymes, particularly COX-1 and COX-2, which are responsible for the synthesis of prostaglandins and thromboxanes. Despite its efficacy, aspirin in its free acid form has poor water solubility and may cause gastrointestinal irritation or ulceration with prolonged use or at high doses.

The formation of the aspirin DL-lysine salt addresses several of these limitations. By reacting acetylsalicylic acid with DL-lysine, a more water-soluble and less acidic compound is produced. This modification enables the preparation of intravenous or intramuscular solutions for emergency clinical applications, such as acute myocardial infarction or thrombotic events, where rapid onset of platelet inhibition is crucial. The lysine component helps buffer the acidity of aspirin, potentially reducing local irritation upon injection or ingestion.

Pharmacologically, aspirin DL-lysine retains all the core effects of acetylsalicylic acid. It is used to relieve pain, reduce fever, decrease inflammation, and inhibit platelet aggregation. The salt rapidly dissociates upon administration, releasing free aspirin and DL-lysine into systemic circulation. The aspirin component exerts its effects by acetylating a serine residue in the active site of COX enzymes, thereby inhibiting the production of prostaglandin precursors and preventing platelet aggregation through reduced thromboxane A₂ synthesis.

This salt form has been particularly valuable in hospital settings for the treatment of acute coronary syndromes and stroke prevention. In such cases, the intravenous route using aspirin DL-lysine allows for rapid absorption and immediate therapeutic effect, which is not achievable with orally administered aspirin. The lysine moiety is pharmacologically inactive in the context of anti-inflammatory or antithrombotic action but contributes to the physicochemical stability and solubility of the compound.

Aspirin DL-lysine has also been explored in oral formulations marketed for rapid relief of pain or fever, especially in patients sensitive to standard aspirin tablets. The improved dissolution rate may lead to faster absorption and onset of action, although the overall pharmacodynamics remain consistent with conventional aspirin therapy.

In terms of safety, aspirin DL-lysine shares the same contraindications and precautions as aspirin. These include risks of gastrointestinal bleeding, peptic ulcer disease, hypersensitivity reactions (particularly in individuals with asthma), and Reye’s syndrome in children with viral infections. At high doses or in prolonged use, systemic side effects such as tinnitus, metabolic acidosis, and renal impairment may occur. The use of DL-lysine as a counterion does not alter the metabolic pathway of aspirin, which is hydrolyzed to salicylic acid and subsequently metabolized in the liver and excreted by the kidneys.

In summary, aspirin DL-lysine is a water-soluble salt of acetylsalicylic acid and DL-lysine designed to improve the solubility, onset, and tolerability of aspirin. It is particularly useful in acute clinical situations requiring rapid platelet inhibition or analgesia and is available in both parenteral and oral formulations. While its pharmacological actions mirror those of conventional aspirin, its enhanced physicochemical properties offer advantages in specific therapeutic contexts.

References

2022. Effects of intravenous lysine acetylsalicylate versus oral aspirin on platelet responsiveness in patients with ST-segment elevation myocardial infarction: the ECCLIPSE-STEMI trial. Journal of Thrombosis and Thrombolysis, 54(4).
DOI: 10.1007/s11239-022-02737-y

2015. Impact of Intravenous Lysine Acetylsalicylate Versus Oral Aspirin on Prasugrel-Inhibited Platelets: Results of a Prospective, Randomized, Crossover Study (the ECCLIPSE Trial). Circulation: Cardiovascular Interventions, 8(6).
DOI: 10.1161/circinterventions.114.002281

2014. Topical nasal lysine aspirin in aspirin-sensitive and aspirin-tolerant chronic rhinosinusitis with nasal polyposis. Expert Review of Clinical Immunology, 10(6).
DOI: 10.1586/1744666x.2014.901889