Formulation and Evaluation of Isradipine Nanosuspension and Exploring its Role as a Potential Anticancer Drug by Computational Approach.

Background: T-type calcium channels are aberrantly expressed in different human cancers and regulate cell cycle progression, proliferation, migration, and survival. FAK-1 can promote tumor protein degradation (p53) through ubiquitination, leading to cancer cell growth and proliferation. Similar findings are obtained regarding protease inhibitors' effect on cytokine-induced neutrophil activation that suppresses Granulocyte-macrophage colony-stimulatingfactor (GM-CSF) TNF-α-induced O2 release and adherence in human neutrophils without affecting phosphorylation of Extracellular signal-regulated kinase (ERK) and p38. Nanosuspensions are carrier-free, submicron colloidal dispersions, which consist of pure drugs and stabilizers. Incorporating drug loaded in nanosuspensions offer a great advantages of passive drug targeting with improved solubility, stability, and bioavailability, as well as lower systemic toxicity.

Objective: The present investigation objective was to establish a molecular association of Protease and Focal Adhesion Kinase 1 as cancer targets for isradipine, a calcium channel blocker (CCB). Furthermore, the study also aimed to formulate its optimized nanosuspension and how the physical, morphological, and dissolution properties of isradipine impact nanosuspension stability.

Methods: Five different molecular targets, namely Cysteine Proteases (Cathepsin B), Serine Proteases (Matriptase), Aspartate Proteases, Matrix Metalloproteases (MMP), and FAK-1 were obtained from RCSB-PDB, which has some potential associations with inhibition in cancer pathogenesis. Molecular interactions of these targets with CCB isradipine were identified and established by molecular simulation docking studies. Isradipine-loaded nanosuspension was prepared by precipitation technique by employing a 2 factorial design. PVP K-30, poloxamer 188, and sodium lauryl sulfate (SLS) were used as polymer, co-polymer, and surfactant, respectively. The nanosuspension particles were assessed for particle size, zeta potential, viscosity, polydispersity index (PDI), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), In-vitro drug release kinetics, and short-term stability study.

Results: Considerable interactions were found with Cysteine, Serine, Aspartate, Threonine, and Matrix metalloproteases with binding energies of -3.91, -6.7, -3.48, -8.42, respectively. Furthermore, the interaction of isradipine with FAK-1 was compared with 7 native ligands and was found to show significant interaction with binding energies of - 8.62, -7.27, -7.69, -5.67, -5.41, -7.44, -8.21, respectively. The optimized nanosuspension was evaluated and exhibited a particle size of 754.9 nm, zeta potential of 32.5 mV, viscosity of 1.287 cp, and PDI of 1.000. The In-vitro dissolution of the optimized formulation (F8) was found to be higher (96.57%) as compared to other formulations.

Conclusion: Isradipine could act as a potential inhibitor of different proteases and FAK-1 associated with tumor growth initiation, progression, and metastasis. Furthermore, isradipine-loaded nanosuspension with optimized release could be utilized to deliver the anticancer drug in a more targeted way as emerging cancer nanotechnology.