Fenamic acid (N-Phenylanthranilic acid, NPAA) is an orally bioactive chloride channel blocker. Fenamic acid is the basic component of non-steroidal anti-inflammatory agents (NSAIA) and can be derived from mefenamic acid, tofenacin, flufenamic acid and melofenac acid. Fenamic acid also works as an antibacterial and analgesic.

Physicochemical Properties

Molecular Formula	C13H11NO2
Molecular Weight	213.23
Exact Mass	213.078
CAS #	91-40-7
PubChem CID	4386
Appearance	Yellow to khaki solid powder
Density	1.3±0.1 g/cm3
Boiling Point	385.2±25.0 °C at 760 mmHg
Melting Point	182-185 °C(lit.)
Flash Point	186.7±23.2 °C
Vapour Pressure	0.0±0.9 mmHg at 25°C
Index of Refraction	1.667
LogP	4.41
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	3
Rotatable Bond Count	3
Heavy Atom Count	16
Complexity	236
Defined Atom Stereocenter Count	0
InChi Key	ZWJINEZUASEZBH-UHFFFAOYSA-N
InChi Code	InChI=1S/C13H11NO2/c15-13(16)11-8-4-5-9-12(11)14-10-6-2-1-3-7-10/h1-9,14H,(H,15,16)
Chemical Name	2-anilinobenzoic acid
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: This product requires protection from light (avoid light exposure) during transportation and storage.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Chloride Channel[1]
ln Vitro	In endothelial cells, fenamic acid (N-Phenylanthranilic acid, NPAA) (2.5 mM; 3 h) inhibits Cl-transport and prevents 36C1-uptake and efflux[1][2]. Fenamic acid suppresses AKR1B10 with IC50s of 0.76 μM for flufenamic acid, 1.6 μM for mefenamic acid, and 9.89 μM for meclofenamic acid, respectively. Fenamic acid shows selectivity to AKR1B10 (the tumor-marker) over human AR[4]. 50% of Neisseria gonorrhoeae with a MIC50 value between 4 and 16 µg/mL (tolfenamic acid, flufenamic acid, and meclofenamic acid) in a low frequency of resistance are inhibited by fenamic acid (4–16 μg/mL; 72 h)[5]. When applied to infected endocervical cells, fenamic acid (2–8 µg/mL; 8 h) decreases the expression of porinflammatory cytokines (IL–8, IL–6, and IL-ß) without inhibiting the cells' ability to bind commensally to Lactobacillus species (>128 µg/mL; 24 h). being a member of a healthy female vaginal microbiota[5].
ln Vivo	RPA-1 is a biomarker used to identify collecting duct damage in male rats with papillary necrosis[3]. In rats, fenamic acid (N-Phenylanthranilic acid, NPAA) (350–700 mg/kg/day; op; 4 d, 8 d, and 15 d) increases urine renal papillary antigen-1 (RPA-1) and promotes renal papillary necrosis[3]. Mice's abdominal constriction caused by acetic acid is inhibited by fenamic acid (20 g/0.2 mL; ip)[6].
Animal Protocol	Animal/Disease Models: Male Wistar Hannover rats (8-10 weeks old; weighting 220-270 g)[3] Doses: 50, 350, or up to 700 mg/kg Route of Administration: Oral gavage; one time/day; 7 days or 14 days Experimental Results: Increased absolute paired kidney weights (13.8% at 350 mg/kg and 21.2% at 700/500 mg/kg) and relative to body weight (10.5% at 350 mg/kg/day and 20.3% at 700/500 mg/kg/day). Caused minimal papillary necrosis of tip with necrosis, hemorrhage, and inflammation of collecting ducts. Animal/Disease Models: Male NMRI mice (weighting 20-25 g); abdominal constriction model (writhing test), induced by acetic acid[6] Doses: 100 g/mL, each mice injected with 20 mL Route of Administration: intraperitoneal (ip) injection; once Experimental Results: demonstrated anti-nociceptive activity and inhibited the abdominal constriction with the maximal inhibition of 96.3% (Mefenamic acid).
References	[1]. Biomarkers of collecting duct injury in Han-Wistar and Sprague-Dawley rats treated with N-phenylanthranilic Acid. Toxicol Pathol. 2012 Jun;40(4):682-94. [2]. Characterization of a cyclic AMP-activated Cl-transport pathway in the apical membrane of a human colonic epithelial cell line. J Biol Chem. 1986 Jan 15. 261(2):704-12. [3]. Chloride efflux in cyclic AMP-induced configurational change of bovine pulmonary artery endothelial cells. Circ Res. 1990 Apr. 66(4):957-67. [4]. Selective inhibition of the tumor marker AKR1B10 by antiinflammatory N-phenylanthranilic acids and glycyrrhetic acid. Biol Pharm Bull. 2010. 33(5):886-90. [5]. Repurposing Fenamic Acid Drugs To Combat Multidrug-Resistant Neisseria gonorrhoeae. Antimicrob Agents Chemother. 2020 Jun 23. 64(7):e02206-19. [6]. Synthesis and analgesic activity of 2-phenoxybenzoic acid and N-phenylanthranilic acid hydrazides. Biol Pharm Bull. 2006 Jun. 29(6):1180-5.
Additional Infomation	Fenamic acid is an aminobenzoic acid that is the N-phenyl derivative of anthranilic acid. It acts as a parent skeleton for the synthesis of several non-steroidal anti-inflammatory drugs. It has a role as a membrane transport modulator. It is a secondary amino compound and an aminobenzoic acid. It is functionally related to an anthranilic acid.

Solubility Data

Solubility (In Vitro)

DMSO: 125 mg/mL (586.22 mM) H2O: < 0.1 mg/mL

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 4.17 mg/mL (19.56 mM) (saturation unknown) in 10% DMSO + 40% PEG300 +5% Tween-80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 41.7 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 + to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	4.6898 mL	23.4489 mL	46.8977 mL
	5 mM	0.9380 mL	4.6898 mL	9.3795 mL
	10 mM	0.4690 mL	2.3449 mL	4.6898 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.