CAPS, cyclohexylaminopropane sulfonic acid, is a surfactant. CAPS can be used as a biological buffer for dialysis (0.05 M, pH 11).

Physicochemical Properties

Molecular Formula	C9H19NO3S
Molecular Weight	221.32
Exact Mass	259.085
CAS #	1135-40-6
Related CAS #	3-(Cyclohexylamino)-1-propanesulfonic Acid-d17;1219804-15-5
PubChem CID	70815
Appearance	White to off-white solid powder
Density	1.2±0.1 g/cm3
Melting Point	>300 °C(lit.)
Index of Refraction	1.515
LogP	0.05
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	5
Heavy Atom Count	14
Complexity	239
Defined Atom Stereocenter Count	0
SMILES	S(C([H])([H])C([H])([H])C([H])([H])N([H])C1([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C1([H])[H])(=O)(=O)O[H]
InChi Key	PJWWRFATQTVXHA-UHFFFAOYSA-N
InChi Code	InChI=1S/C9H19NO3S/c11-14(12,13)8-4-7-10-9-5-2-1-3-6-9/h9-10H,1-8H2,(H,11,12,13)
Chemical Name	3-(cyclohexylamino)propane-1-sulfonic 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
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

ln Vitro	Because amines do not ionize at high pH values, CAPS surfactants have a single negative charge [1].
References	[1]. Ion Interaction: The Energetics and Mechanism of The Competitive Behavior Between Two Similarly Charged Molecules. 1. The Effect of Ionic Strength, Acetonitrile and Surfactant Concentration. Journal of Liquid Chromatography, 1985, 8(13):2417-2443. [2]. The effect of the dimeric and multimeric forms of fibronectin on the adhesion and growth of primary glomerular cells. Exp Cell Res. 1983 May;145(2):265-76.
Additional Infomation	Cyclohexylaminopropanesulfonic acid is an amine.

Solubility Data

Solubility (In Vitro)

H2O : ~125 mg/mL (~564.79 mM) DMSO : ~5 mg/mL (~22.59 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 0.5 mg/mL (2.26 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 5.0 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: ≥ 0.5 mg/mL (2.26 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 5.0 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.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	4.5183 mL	22.5917 mL	45.1834 mL
	5 mM	0.9037 mL	4.5183 mL	9.0367 mL
	10 mM	0.4518 mL	2.2592 mL	4.5183 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.