Benzolamide (CL11366) is a potent carbonic anhydrase (CA) inhibitor (antagonist) with Kis of 15 nM, 9 nM, 94 nM and 78 nM for hCA I, hCA II, EcoCAγ and VchCAγ respectively. Benzolamide also inhibits CAS3 with a Ki of 54 nM. Benzolamide may be used in research into glaucoma and epilepsy.

Physicochemical Properties

Molecular Formula	C8H8N4O4S3
Molecular Weight	320.37
Exact Mass	319.971
CAS #	3368-13-6
PubChem CID	18794
Appearance	White to light yellow solid powder
Density	1.746g/cm3
Boiling Point	585.9ºC at 760mmHg
Flash Point	308.2ºC
Index of Refraction	1.689
LogP	2.921
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	9
Rotatable Bond Count	4
Heavy Atom Count	19
Complexity	503
Defined Atom Stereocenter Count	0
InChi Key	PWDGTQXZLNDOKS-UHFFFAOYSA-N
InChi Code	InChI=1S/C8H8N4O4S3/c9-18(13,14)8-11-10-7(17-8)12-19(15,16)6-4-2-1-3-5-6/h1-5H,(H,10,12)(H2,9,13,14)
Chemical Name	5-(benzenesulfonamido)-1,3,4-thiadiazole-2-sulfonamide
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	CA Ⅱ
ln Vitro	Benzolamide inhibits hCA I, hCA II, EcoCAγ, and VchCAγ with corresponding Ki values of 15 nM, 9 nM, 94 nM, and 78 nM [1]. Whereas CAS1 (Ki=2115 nM) and CAS2 (Ki= 410 nm) are less selective than CAS3 (Ki=54 nM) when it comes to benzonzoamide [2].
ln Vivo	Rats treated with benzolamide (90 μmol/kg; intraperitoneally) have lower brain pH and fewer electroencephalographic post-asphyxia epileptic episodes[3].
Animal Protocol	Animal/Disease Models: Male and female Wistar Han rats (11-day-old)[3] Doses: 90 µmol/kg Route of Administration: A single ip Experimental Results: Induced a fast brain acidosis of a comparable magnitude. Suppressed electrographic seizures after asphyxia by slowing down the recovery of brain pH.
References	[1]. Escherichia coli γ-carbonic anhydrase: characterisation and effects of simple aromatic/heterocyclic sulphonamide inhibitors. J Enzyme Inhib Med Chem. 2020 Dec;35(1):1545-1554. [2]. Sulfonamide Inhibition Studies of the β-Class Carbonic Anhydrase CAS3 from the Filamentous Ascomycete Sordaria macrospora. Molecules. 2020 Feb 25;25(5):1036. [3]. Carbonic anhydrase inhibitors suppress seizures in a rat model of birth asphyxia. Epilepsia. 2021 Jun 27.
Additional Infomation	Selective renal carbonic anhydrase inhibitor. It may also be of use in certain cases of respiratory failure.

Solubility Data

Solubility (In Vitro)

DMSO: 250 mg/mL (780.35 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.08 mg/mL (6.49 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 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 20.8 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. Solubility in Formulation 2: ≥ 2.08 mg/mL (6.49 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in 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 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 2.08 mg/mL (6.49 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (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 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.1214 mL	15.6070 mL	31.2139 mL
	5 mM	0.6243 mL	3.1214 mL	6.2428 mL
	10 mM	0.3121 mL	1.5607 mL	3.1214 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.