Diclofenac Potassium / Sodium

Product Story

Diclofenac was synthesized in 1973 by Alfred Sallmann and Rudolf Pfister at Ciba-Geigy (now Novartis) in Basel, Switzerland. The discovery emerged from a systematic medicinal chemistry program to develop a non-steroidal anti-inflammatory drug with improved potency over existing options like indomethacin and phenylbutazone. The research team deliberately pursued a phenylacetic acid scaffold — structurally distinct from the propionic acid derivatives (ibuprofen, naproxen) and salicylates (aspirin) that dominated the NSAID class. The para-dichlorophenyl substitution and the 2,6-dichloroanilino motif proved critical to potency: diclofenac inhibits cyclooxygenase enzymes (COX-1 and COX-2) at roughly 10-50 times the potency of ibuprofen on a molar basis.

Diclofenac was first launched in Japan in 1974 under the brand name Voltaren (from the German "Volt" for voltage and "-aren" from the arylethanoic acid class), and rapidly became one of the most prescribed NSAIDs globally. Its clinical success reflects a genuinely differentiated profile: high potency at COX inhibition, good tissue penetration (synovial fluid concentrations exceed plasma levels within hours), and versatile formulation options. The introduction of diclofenac potassium in the 1990s addressed the one limitation of the sodium salt — slow absorption — by leveraging the higher aqueous solubility of the potassium salt to achieve peak plasma levels in 15-30 minutes rather than 1-2 hours. A 2015 Cochrane systematic review confirmed that diclofenac potassium provides effective pain relief within 30-60 minutes at the 50 mg dose for acute post-operative pain, placing it among the most effective single-dose oral analgesics.

The two salt forms serve complementary therapeutic roles. Diclofenac sodium (MW 318.13) is used in delayed-release, sustained-release, and enteric-coated formulations for chronic inflammatory conditions — osteoarthritis, rheumatoid arthritis, ankylosing spondylitis — where sustained 24-hour COX inhibition matters more than speed of onset. Diclofenac potassium (MW 334.24) is formulated in immediate-release tablets and soluble powders for acute pain indications — migraine (50 mg), dental pain, post-operative pain, acute gout flares — where rapid plasma levels drive clinical efficacy. Both salts contain the identical active moiety (diclofenac free acid); the counter-ion difference affects only the dissolution and absorption rate, not the pharmacological activity or ultimate bioavailability.

As of mid-2026, diclofenac remains on the WHO Model List of Essential Medicines and is one of the highest-volume NSAID APIs globally, with annual consumption measured in thousands of metric tons. China and India are the dominant manufacturing sources for generic diclofenac API. The market is mature and highly competitive, with quality differentiation separating GMP-certified manufacturers from lower-tier suppliers. Key quality issues in the API supply chain include control of the cyclooxygenase-related impurity profile (particularly diclofenac-related compound A, an indolinone degradant), polymorphic consistency, and trace elemental impurities per ICH Q3D. KingWish supplies diclofenac sodium and potassium salts meeting USP, EP, and CP standards, with full analytical documentation.

Quality Specifications

Therapeutic Applications

Additional Applications

• Ophthalmic preparations: Diclofenac sodium 0.1% eye drops for post-operative ocular inflammation and pain after cataract surgery.
• Injectable formulations: Diclofenac sodium 75 mg/3 ml solution for intramuscular administration in acute severe pain when oral route is unavailable.
• Topical formulations: 1% diclofenac sodium gel, 1.3% or 2% diclofenac sodium patch, and 1.5% diclofenac sodium topical solution for localized musculoskeletal pain.
• Suppository formulations: 12.5/25/50/100 mg for patients unable to take oral medication.