What certifications should a reliable aspirin API supplier hold?

At minimum, the supplier should hold a valid GMP certificate (ICH Q7) and provide batch-specific CoA with HPLC assay data. For regulated markets, an active DMF (US FDA) or CEP (EDQM) adds substantial credibility. Request the residual solvent statement and elemental impurity risk assessment per ICH Q3D. A supplier's willingness to share these documents before receiving a purchase order is itself a strong reliability signal.

Acetylsalicylic Acid | CAS 50-78-2 | Pharma API Supplier

Name: Acetylsalicylic Acid
SKU: 50-78-2
Availability: InStock

Acetylsalicylic Acid pharmaceutical raw material

Quick Facts

CAS Number	50-78-2
Molecular Formula	C9H8O4
Molecular Weight	180.16
Pharmacopoeia	USP, EP, CP
Packaging	25 KG/DRUM

USP Standard EP/BP Standard

Product Overview

Acetylsalicylic acid was first synthesized in a pure and stable form by Felix Hoffmann at Bayer in 1897, building on centuries of traditional use of willow bark (which contains the prodrug salicin). Bayer launched it as Aspirin in 1899, and it remains one of the most widely consumed medications globally — with over 40,000 metric tons produced annually as of 2025. The compound's mechanism was not elucidated until 1971, when John Vane discovered that it works by irreversibly inhibiting cyclooxygenase (COX-1 and COX-2), a finding that earned him the 1982 Nobel Prize in Physiology or Medicine.

Unlike most NSAIDs, aspirin's irreversible acetylation of COX-1 in platelets produces a lasting antiplatelet effect that persists for the platelet's entire 7-10 day lifespan. This unique property makes low-dose aspirin (75-100 mg) a cornerstone of cardiovascular disease prevention, reducing the risk of recurrent myocardial infarction and ischemic stroke. No other NSAID shares this irreversible, long-duration antiplatelet mechanism.

The dual-dose utility of aspirin API — high-dose (300-1000 mg) for analgesia and inflammation, low-dose for antiplatelet therapy — makes it one of the most versatile bulk APIs in pharmaceutical manufacturing. It serves as the active ingredient in tablets, effervescent powders, enteric-coated formulations, and fixed-dose combinations. The compound is also the starting material for derivatives such as diflunisal and the prodrug benorylate.

As of mid-2026, global aspirin API production is concentrated in China, which accounts for an estimated 60-70% of worldwide output, with key manufacturing hubs in Shandong, Hebei, and Jiangsu provinces. The aspirin API market was valued at approximately USD 1.68 billion in 2024 and continues to grow at roughly 4% CAGR, driven by aging populations and expanding cardiovascular prophylaxis guidelines in emerging markets. KingWish supplies GMP-certified acetylsalicylic acid meeting USP, EP, and CP standards, supporting pharmaceutical manufacturers worldwide.

Quality Specifications

Assay (HPLC, dried basis)	99.5% - 101.0% (USP/EP)
Free Salicylic Acid	≤ 0.05% (USP); ≤ 0.1% (EP)
Loss on Drying	≤ 0.5%
Heavy Metals	≤ 10 ppm
Residual Solvents	Compliant with ICH Q3C; Class 2 solvents ≤ limits
GMP Status	Manufactured under ICH Q7 GMP conditions

Applications

Analgesic and antipyretic: Oral tablets and powders for pain relief and fever reduction. One of the most widely used OTC APIs worldwide.
Cardiovascular prophylaxis: Low-dose formulations (75-100 mg) for antiplatelet therapy and cardiovascular event prevention. Irreversible COX-1 inhibitor.
Anti-inflammatory therapy: Key NSAID API for reducing inflammation in rheumatoid arthritis, osteoarthritis, and acute musculoskeletal conditions.
Thrombosis prevention: Cornerstone of dual antiplatelet therapy post-stent placement, combined with P2Y12 inhibitors.

Sourcing Acetylsalicylic Acid: Key Checks

Documentation

Request CoA with HPLC assay data, free salicylic acid content, and residual solvent statement (ICH Q3C). Verify loss on drying and heavy metals. For regulated markets, confirm DMF or CEP filing status.

Red Flags

Elevated free salicylic acid above 0.1% indicates degradation or poor synthesis control. Vinegar-like odor from opened samples suggests moisture exposure and hydrolysis. Vague pharmacopoeia claims without batch-specific data.

Packaging & Logistics

Standard: 25 KG/DRUM with inner PE liner. Must be stored at 15-25 degrees Celsius, protected from moisture and light. Ship containers with desiccant. Standard lead time 4-6 weeks depending on regulatory documentation.

Market Context

Global aspirin API market valued at ~USD 1.68 billion in 2024, growing at ~4% CAGR. China accounts for 60-70% of global production. Demand driven by aging populations and expanding cardiovascular prophylaxis guidelines. Market report

Frequently Asked Questions

They are the same molecule. Acetylsalicylic acid is the chemical name (INN); Aspirin is Bayer's original trade name from 1899 that became a genericized trademark in many countries. Both refer to CAS 50-78-2, C₉H₈O₄. As an API buyer, the key distinction is pharmacopoeia grade — USP, EP, or CP — not the naming convention.

The most important specification is free salicylic acid content — limited to ≤ 0.05% in USP and ≤ 0.1% in EP — as salicylic acid is both a degradation product and a gastric irritant. Also verify assay (99.5-101.0% on dried basis per USP), total impurities by HPLC, residual solvents per ICH Q3C, and heavy metals (≤ 10 ppm). For sustained-release formulations, particle size distribution should also be specified in the quality agreement.

Acetylsalicylic acid is moisture-sensitive: it hydrolyzes back to salicylic acid and acetic acid in the presence of water. The characteristic vinegar odor in old aspirin bottles indicates this degradation. API should be stored at 15-25 degrees Celsius in airtight containers with desiccant, protected from humidity. The USP specifies a loss on drying of ≤ 0.5%. Improper storage during shipping or warehousing can reduce shelf life and push free salicylic acid content beyond pharmacopoeia limits.

At minimum, the supplier should hold a valid GMP certificate (ICH Q7) and provide batch-specific CoA with HPLC assay data. For regulated markets, an active DMF (US FDA) or CEP (EDQM) adds substantial credibility. Also request the residual solvent statement and elemental impurity risk assessment per ICH Q3D. KingWish provides all these documents and welcomes pre-order quality audits. A supplier's willingness to share complete documentation before receiving a purchase order is itself a strong reliability signal.

Standards: USP, EP, CP | CAS: 50-78-2 | Quality data verified against pharmacopoeia monograph COA and MSDS available | DrugBank | July 2026