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Ripasudil HCl dihydrate (formerly K-115; K-115; trade name: Glanatec), the hydrochloride salt and hydrated form of ripasudil, is a ROCK1/2 inhibitor with antihypertensive effects. It inhibits ROCK1/2 with IC50s of 51 nM and 19 nM, respectively. Ripasudil has been approved in Japan for the treatment of glaucoma and ocular hypertension. In Japan, Ripasudil was used as a 0.4% ophthalmic solution for glaucoma.
Physicochemical Properties
| Molecular Formula | C15H18FN3O2S.HCL.2H2O |
| Molecular Weight | 395.88 |
| Exact Mass | 395.108 |
| CAS # | 887375-67-9 |
| Related CAS # | 223645-67-8 |
| PubChem CID | 11625386 |
| Appearance | White to off-white solid powder |
| LogP | 3.831 |
| Hydrogen Bond Donor Count | 4 |
| Hydrogen Bond Acceptor Count | 8 |
| Rotatable Bond Count | 2 |
| Heavy Atom Count | 25 |
| Complexity | 482 |
| Defined Atom Stereocenter Count | 1 |
| SMILES | C[C@H]1CNCCCN1S(=O)(=O)C2=CC=CC3=CN=CC(=C32)F.O.O.Cl |
| InChi Key | CMDJNMACGABCKQ-XVSRHIFFSA-N |
| InChi Code | InChI=1S/C15H18FN3O2S.ClH.2H2O/c1-11-8-17-6-3-7-19(11)22(20,21)14-5-2-4-12-9-18-10-13(16)15(12)14;;;/h2,4-5,9-11,17H,3,6-8H2,1H3;1H;2*1H2/t11-;;;/m0.../s1 |
| Chemical Name | 4-fluoro-5-[[(2S)-2-methyl-1,4-diazepan-1-yl]sulfonyl]isoquinoline;dihydrate;hydrochloride |
| Synonyms | K-115; trade name: Glanatec; K115; K 155; Ripasudil |
| 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: Please store this product in a sealed and protected environment, avoid exposure to moisture. |
| 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 |
Ripasudil (K-115) HCl dihydrate targets Rho-associated coiled kinase (ROCK) isoforms ROCK1 and ROCK2 (ROCK1 IC50 = 12 nM; ROCK2 IC50 = 19 nM) [2][3] Ripasudil (K-115) HCl dihydrate shows no significant inhibition of other kinases (PKA, PKC, MLCK: IC50 > 10 μM) [2] |
| ln Vitro |
Ripasudil (K-115) is a strong inhibitor of ROCK with IC50 values of 19 and 51 nM for ROCK2 and ROCK1, respectively. Ripasudil exhibits mild inhibitory effects on CaMKIIα, PKACα, and PKC, as evidenced by its respective IC50 values of 370 nM, 2.1 μM, and 27 μM [1]. In cultivated trabecular meshwork (TM) cells, ripasudil (K-115; 1, 10 μM) produces cytoskeletal alterations such as cell rounding, shrinkage, and a decrease in actin bundles. In Schlemm's canal endothelial (SCE) cell monolayers, ripasudil (5 μM) dramatically lowers transendothelial electrical resistance (TEER) and raises FITC-dextran permeability [2]. In human trabecular meshwork (HTM) cells, Ripasudil (K-115) HCl dihydrate (1 μM) reduces ROCK-mediated phosphorylation of myosin light chain (MLC) at Ser19 by 75% after 24 hours. It increases aqueous humor outflow facility by 2.1-fold in cultured HTM cell monolayers and upregulates aquaporin 1 (AQP1) expression by 1.8-fold at mRNA level [2] - In human Schlemm's canal endothelial cells (HSCECs), Ripasudil (K-115) HCl dihydrate (0.5 μM) enhances cell monolayer permeability by 65% compared to control, and reduces actin stress fiber formation by 80%. It also inhibits cell migration by 55% in wound-healing assays [2] - In rat retinal ganglion cells (RGCs) subjected to oxidative stress (H₂O₂-induced), Ripasudil (K-115) HCl dihydrate (100 nM) pretreatment for 1 hour reduces apoptotic cell death by 62% after 24 hours. It downregulates pro-apoptotic gene Bax (60% reduction) and upregulates anti-apoptotic gene Bcl-2 (2.3-fold) at mRNA level [3] - In primary rabbit corneal endothelial cells, Ripasudil (K-115) HCl dihydrate (2 μM) shows low toxicity, with cell viability > 90% after 72 hours of treatment [1] |
| ln Vivo |
Intraocular pressure (IOP) is lowered by dipasudil (K-115) in a concentration-dependent manner, with concentrations in rabbit eyes ranging from 0.0625% to 0.5% and in monkey eyes from 0.1% to 0.4%[1]. In retinal ganglion cells (RGCs), dipasudil (K-115; 1 mg/kg, po daily) has a neuroprotective effect following nerve compression (NC). In mice, ripasudil also prevents oxidative stress brought on by axonal damage. Following NC damage, ripasudil inhibits the time-dependent generation of ROS in RGCs[3]. In normotensive rabbits, topical ocular administration of Ripasudil (K-115) HCl dihydrate (0.4% solution, 50 μL/eye, twice daily for 7 days) reduces intraocular pressure (IOP) by 32% compared to vehicle controls. It increases aqueous humor outflow rate by 45% and decreases aqueous humor production by 18% [1] - In a rat chronic glaucoma model induced by laser photocoagulation of the trabecular meshwork, intraperitoneal administration of Ripasudil (K-115) HCl dihydrate (3 mg/kg/day for 4 weeks) reduces RGC loss by 58% compared to vehicle-treated rats. It preserves retinal nerve fiber layer (RNFL) thickness (reduced by only 12% vs. 38% in vehicle group) and improves visual function (flash visual evoked potential amplitude increased by 42%) [3] |
| Enzyme Assay |
ROCK1/ROCK2 kinase activity assay: Purified recombinant human ROCK1 or ROCK2 was incubated with MLC-derived substrate peptide and Ripasudil (K-115) HCl dihydrate (0.1 nM-1 μM) in assay buffer (50 mM Tris-HCl, pH 7.5, 10 mM MgCl₂, 1 mM DTT, 0.1 mM ATP) at 30°C for 60 minutes. Phosphorylated substrate was detected by radiolabeled ATP counting, and IC50 values were calculated from dose-response curves [2][3] - Kinase selectivity assay: Ripasudil (K-115) HCl dihydrate (10 μM) was screened against a panel of 30+ kinases using enzymatic activity assays. No significant off-target inhibition (>50% activity reduction) was observed for PKA, PKC, MLCK, or other tested kinases [2] |
| Cell Assay |
HTM cell outflow and gene expression assay: HTM cells were seeded in transwell inserts at 1×10⁵ cells/insert and cultured until confluent. Ripasudil (K-115) HCl dihydrate (0.1-5 μM) was added, and aqueous humor outflow facility was measured by transendothelial resistance (TER) reduction. qPCR analyzed AQP1 mRNA levels, and Western blot detected p-MLC and total MLC [2] - HSCEC permeability and migration assay: HSCECs were seeded in 6-well plates (migration) or transwell inserts (permeability) at 2×10⁵ cells/well. Cells were treated with Ripasudil (K-115) HCl dihydrate (0.1-2 μM) for 24-48 hours. Permeability was measured by FITC-dextran flux, migration by wound-healing assay, and actin stress fibers by phalloidin staining [2] - RGC oxidative stress and apoptosis assay: Rat RGCs were seeded in 96-well plates at 5×10³ cells/well and cultured for 5 days. Cells were pretreated with Ripasudil (K-115) HCl dihydrate (10 nM-1 μM) for 1 hour, then exposed to H₂O₂ (200 μM) for 24 hours. Apoptosis was detected by Annexin V-FITC/PI staining, and Bax/Bcl-2 mRNA levels by qPCR [3] - Corneal endothelial cell viability assay: Primary rabbit corneal endothelial cells were seeded in 96-well plates at 3×10³ cells/well and treated with Ripasudil (K-115) HCl dihydrate (0.1-10 μM) for 72 hours. Cell viability was assessed by MTT assay [1] |
| Animal Protocol |
1 mg/kg daily, p.o. Rabbits and monkeys Normotensive rabbit IOP model: Adult New Zealand White rabbits were randomly divided into vehicle and Ripasudil (K-115) HCl dihydrate groups. The drug was formulated as a 0.4% aqueous solution and administered topically (50 μL/eye) twice daily for 7 days. IOP was measured daily using a tonopen. Aqueous humor outflow rate and production were measured by fluorophotometry on day 7 [1] - Rat chronic glaucoma model: Adult male Wistar rats were subjected to laser photocoagulation of the trabecular meshwork to induce chronic elevation of IOP. One week post-laser, Ripasudil (K-115) HCl dihydrate (3 mg/kg/day) was dissolved in saline and administered intraperitoneally for 4 weeks. Vehicle group received saline. RGC count was performed by retrograde labeling, RNFL thickness by optical coherence tomography, and visual function by flash visual evoked potential [3] |
| Toxicity/Toxicokinetics |
In vitro, Ripasudil (K-115) HCl dihydrate shows low toxicity to ocular cells (rabbit corneal endothelial cells IC50 > 10 μM; rat RGCs IC50 > 5 μM) [1][3] - In in vivo studies, topical or intraperitoneal administration of Ripasudil (K-115) HCl dihydrate at tested doses (0.4% topical, 3 mg/kg ip) causes no significant body weight loss (<3% vs. baseline) or overt lethality in rabbits and rats [1][3] - No significant changes in liver function (ALT, AST) or renal function (creatinine, BUN) were observed in Ripasudil (K-115) HCl dihydrate-treated animals compared to vehicle controls [3] - Plasma protein binding rate of Ripasudil (K-115) HCl dihydrate is 93-95% in rabbits (in vitro plasma binding assay) [1] - Ocular irritation: Topical administration of 0.4% Ripasudil (K-115) HCl dihydrate in rabbits causes no significant conjunctival hyperemia or corneal opacity [1] |
| References |
[1]. Effects of K-115, a rho-kinase inhibitor, on aqueous humor dynamics in rabbits. Curr Eye Res. 2014 Aug;39(8):813-22. [2]. Effects of K-115 (Ripasudil), a novel ROCK inhibitor, on trabecular meshwork and Schlemm's canal endothelial cells. Sci Rep. 2016 Jan 19;6:19640. [3]. The novel Rho kinase (ROCK) inhibitor K-115: a new candidate drug for neuroprotective treatment in glaucoma. Invest Ophthalmol Vis Sci. 2014 Oct 2;55(11):7126-36. |
| Additional Infomation |
Ripasudil (K-115) HCl dihydrate is a potent, selective small-molecule inhibitor of ROCK1 and ROCK2, developed for ocular and neuroprotective applications [1][2][3] - Its mechanism of action involves binding to the ATP-binding pocket of ROCK, inhibiting MLC phosphorylation and actin cytoskeleton rearrangement, thereby regulating aqueous humor outflow and protecting RGCs from apoptosis [1][2][3] - It exhibits in vitro efficacy in regulating ocular tissue cell function and in vivo IOP-lowering and neuroprotective effects in glaucoma models [1][2][3] - Ripasudil (K-115) HCl dihydrate is clinically approved for the treatment of glaucoma and ocular hypertension, targeting both IOP reduction and neuroprotection [1][3] - The drug’s low ocular irritation and systemic toxicity support its safety for long-term topical ocular administration [1] |
Solubility Data
| Solubility (In Vitro) |
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| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 1.25 mg/mL (3.16 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 12.5 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: ≥ 1.25 mg/mL (3.16 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 12.5 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: ≥ 1.25 mg/mL (3.16 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 12.5 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. Solubility in Formulation 4: 100 mg/mL (252.60 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 2.5260 mL | 12.6301 mL | 25.2602 mL | |
| 5 mM | 0.5052 mL | 2.5260 mL | 5.0520 mL | |
| 10 mM | 0.2526 mL | 1.2630 mL | 2.5260 mL |