Sustained intravitreal dissolution and kinase inhibition by an inhibitory cGMP analogue after its injection as a suspension of a poorly soluble salt - 21/05/26
, Elisa Toropainen a, Simar Pal Singh b, Annika Valtari a, Ali Koskela a, Arto Merivaara a, Oswaldo Perez c, Marika Ruponen a, John Groten b, Nicolaas Schipper c, Arto Urtti a, Kati-Sisko Vellonen a, Tatu Lajunen a, Jooseppi Puranen aAbstract |
Retinitis pigmentosa (RP) is an inherited and untreatable retinal dystrophy that leads to blindness at an early age. Cyclic guanosine monophosphate analogue, 8- bromo- β- phenyl- 1, N²- ethenoguanosine- 3′, 5′- cyclic monophosphorothioate Rp- isomer (CN03), has shown preclinical promise as systemic treatment in an RP mouse model. We explored intravitreal (IVT) CN03 delivery and resulting biochemical responses in rabbits. To prolong activity, we used poorly water-soluble benethamine (BNE) and benzathine (BNZ) salts to sustain CN03 release. Crystallinity, particle size, and solubility of CN03-BNE (385.4 ± 37.07 µM) and CN03-BNZ (275.9 ± 9.24 µM) in vitreous humor were determined. Suspension of 15% CN03-BNZ showed dissolution half-life of 7.40 ± 0.86 days in vitro and CN03 release of one month after IVT injection in rabbits . Ex vivo in retina lysates, CN03 showed concentration-dependent inhibition of PKG kinases. Furthermore, downregulation of PKG-related kinases and RP-linked cellular pathways (e.g., calmodulin, PI3K-AKT-mTOR, and NF-κB) in rabbit retina and peripheral blood monocytes (PBMC) were seen after IVT injection of CN03-BNZ suspension. Kinase inhibition profiles in the retina and PBMCs overlapped, but plasma CN03 levels were much lower than in the retina. PBMC kinase activity is a potential biomarker for retinal kinase inhibition, warranting further studies in disease state models. Overall, intravitreal delivery of cGMP analogue CN03 as a poorly water-soluble salt demonstrates kinase inhibition and sustained ocular delivery. These results lay the foundation for further translational studies towards intravitreal treatment of the RP with cGMP analogues.
Le texte complet de cet article est disponible en PDF.Graphical Abstract |
Highlights |
• | CN03-BNZ suspension releases CN03 in the rabbit vitreous up to one month. |
• | 30 µM CN03 inhibits CAMK, CMGC, and AGC kinases in rabbit retina cell lysates. |
• | Intravitreal CN03-BNZ inhibits retinitis pigmentosa-relevant pathways in vivo. |
• | Kinase inhibition profile in rabbit PBMCs and retina overlaps after CN03-BNZ. |
Abbreviations : BNE, BNZ, CGMP, CGNC, CN03, DMSO, FDR, HPLC, IC 50 , ISTD, IVT, LLOQ, MFS, MKS, MRM, MSiS, MSpS, MTvC, PBMC, PBS, Phosphosite, PKG, QC, QQQ, RP, STK, UKA
Key words : Intravitreal injection, Retinitis pigmentosa, Pharmacokinetics, Suspension, Drug release, cGMP analogue, Kinase inhibition
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Vol 199
Article 119387- juin 2026 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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