PEGylated mesoporous silica core-shell redox-responsive nanoparticles for delivering paclitaxel to breast cancer cells.

Controlling the drug release and restricting its presence in healthy organs is extremely valuable. In this study, mesoporous silica nanoparticles (MSN) as the core, loaded with paclitaxel (PTX), were coated with a non-porous silica shell functionalized with disulfide bonds. The nanoparticles were further coated with polyethylene glycol (PEG) via disulfide linkages. We analyzed the physicochemical properties of nanoparticles, including hydrodynamic size via Dynamic Light Scattering (DLS), zeta potential, X-ray Diffraction (XRD) patterns, Fourier-Transform Infrared (FTIR) spectra, and imaging through Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The drug release profile in two distinct glutathione (GSH) concentrations of 2 µM and 10 µM was measured. The cellular uptake of nanoparticles by MCF-7 cell line was determined using Confocal Laser Scanning Microscopy (CLSM) images and flow cytometry. Furthermore, the cell viability and the capability of nanoparticles to induce apoptosis in MCF-7 cell line were studied using the MTT assay and flow cytometry, respectively. Our investigations revealed that the release of PTX from the drug delivery system was redox-responsive. Also, results indicated an elevated level of cellular uptake and efficient induction of apoptosis, underscoring the promising potential of this redox-responsive drug delivery system for breast cancer therapy.

Triamcinolone-loaded self nano-emulsifying drug delivery systems for ocular use: An alternative to invasive ocular surgeries and injections.

Inflammation of the posterior segment of the eye is a severe condition and hard to cure as delivery of drugs to the inflammation site is inefficient. Currently, the primary treatment approach is ocular surgery or invasive ocular injections. Herein, we designed and developed a topically self nano-emulsifying drug delivery system (SNEDDs) to deliver triamcinolone acetonide (TCA) to the posterior segment of the eye. A screening based on TCA solubility was conducted on each excipient followed by preparation of various formulations using different ratios of the selected excipients. Vesicles of optimized SNEDDs had less than 100 nm size and spherical morphology. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay showed self-emulsified vesicles have relatively high safety on retinal pigment epithelium (RPE) cell line. Furthermore, efficient cellular uptake of coumarin 6-loaded SNEDDs in RPE using confocal laser scanning microscopy (CLSM) was confirmed. In addition, an in-vivo study using hematoxylin and eosin (H&E) staining revealed that 14 days of topical treatment of albino rabbit eyes with TCA-loaded SNEDDs was safe and no sign of tissue destruction and inflammation was detected in different parts of the eye sections including cornea, sclera, retina, and optic nerve. Also, the CLSM images from topically treated eyes with coumarin 6 (a hydrophobic, fluorescent drug model) loaded SNEDDs, showed that the optimized SNEDDs could properly penetrate toward the posterior segments of the eye especially the retina, posterior parts of the choroid, and sclera. Considering the outstanding results obtained by ocular tissue penetration and low toxicity, prepared SNEDDs, have the potential to be used as a topical administration for treating posterior segment disorders of the eye through an utterly non-invasive route and TCA-loaded SNEDDs could be an alternative for TCA intravitreal and intra conjunctival injections.