Oleogels for the ocular delivery of epalrestat: formulation, in vitro, in ovo, ex vivo and in vivo evaluation.

The ocular administration of lipophilic and labile drugs such as epalrestat, an aldose reductase inhibitor with potential for diabetic retinopathy treatment, demands the development of topical delivery systems capable of providing sufficient ocular bioavailability. The aim of this work was to develop non-aqueous oleogels based on soybean oil and gelators from natural and sustainable sources (ethyl cellulose, beeswax and cocoa butter) and to assess their reproducibility, safety and efficiency in epalrestat release and permeation both ex vivo and in vivo. Binary combinations of gelators at 10% w/w resulted in solid oleogels (oleorods), while single gelator oleogels at 5% w/w remained liquid at room temperature, with most of the oleogels displaying shear thinning behavior. The oleorods released up to 4 µg epalrestat per mg of oleorod in a sustained or burst pattern depending on the gelator (approx. 10% dose in 24 h). The HET-CAM assay indicated that oleogel formulations did not induce ocular irritation and were safe for topical ocular administration. Corneal and scleral ex vivo assays evidenced the permeation of epalrestat from the oleorods up to 4 and 2.5 µg/cm2 after six hours, respectively. Finally, the capacity of the developed oleogels to sustain release and provide significant amounts of epalrestat to the ocular tissues was demonstrated in vivo against aqueous-based niosomes and micelles formulations loaded with the same drug concentration. Overall, the gathered information provides valuable insights into the development of oleogels for ocular drug delivery, emphasizing their safety and controlled release capabilities, which have implications for the treatment of diabetic neuropathy and other ocular conditions.

Gemcitabine-Vitamin E Prodrug-Loaded Micelles for Pancreatic Cancer Therapy.

Pancreatic cancer (PC) is an aggressive cancer subtype presenting unmet clinical challenges. Conventional chemotherapy, which includes antimetabolite gemcitabine (GEM), is seriously undermined by a short half-life, its lack of targeting ability, and systemic toxicity. GEM incorporation in self-assembled nanosystems is still underexplored due to GEM's hydrophilicity which hinders efficient encapsulation. We hypothesized that vitamin E succinate-GEM prodrug (VES-GEM conjugate) combines hydrophobicity and multifunctionalities that can facilitate the development of Pluronic® F68 and Pluronic® F127 micelle-based nanocarriers, improving the therapeutic potential of GEM. Pluronic® F68/VES-GEM and Pluronic® F127/VES-GEM micelles covering a wide range of molar ratios were prepared by solvent evaporation applying different purification methods, and characterized regarding size, charge, polydispersity index, morphology, and encapsulation. Moreover, the effect of sonication and ultrasonication and the influence of a co-surfactant were explored together with drug release, stability, blood compatibility, efficacy against tumour cells, and cell uptake. The VES-GEM conjugate-loaded micelles showed acceptable size and high encapsulation efficiency (>95%) following an excipient reduction rationale. Pluronic® F127/VES-GEM micelles evidenced a superior VES-GEM release profile (cumulative release > 50%, pH = 7.4), stability, cell growth inhibition (<50% cell viability for 100 µM VES-GEM), blood compatibility, and extensive cell internalization, and therefore represent a promising approach to leveraging the efficacy and safety of GEM for PC-targeted therapies.

Biomechanical characteristics of different methods of neo-chordal fixation to the papillary muscles.

BACKGROUND AND AIM OF THE STUDY: Several techniques have been described for neo-chordal fixation to the papillary muscles without any reported clinical differences. The objective of this study is to compare in vitro the biomechanical properties of four of these common techniques. METHODS: We studied the biomechanical properties of expanded polytetrafluoroethylene neo-chordal fixation using four techniques: nonknotted simple stitch, nonknotted figure-of-eight stitch, knotted pledgeted mattress stitch, and knotted pledgeted stitch using commercially available prefabricated loops. Neo-chordae were submitted to a total of 20 traction-relaxation cycles with incremental loads of 1, 2, and 4 N. We calculated the elongation, the force-strain curve, elasticity, and the maximum tolerated load before neo-chordal failure. RESULTS: The elongation of the neo-chordae was lowest in the simple stitch followed by the figure-of-eight, the pledgeted mattress, and he commercially prefabricated loops (p < .001). Conversely, the elastic modulus was highest in the simple stitch followed by the figure-of-eight, the pledgeted mattress, and the prefabricated loops (p < .001). The maximum tolerated load was similar with the simple stitch (28.87 N) and with the figure-of-eight stitch (31.39 N) but was significantly lower with the pledgeted mattress stitch (20.51 N) and with the prefabricated loops (7.78 N). CONCLUSION: In vitro, neo-chordal fixation by nonknotted simple or nonknotted figure-of-eight stitches resulted in less compliance as opposed to the use of knotted pledgeted stitches. Fixation technique seemed to influence neo-chordal biomechanical properties, however, it did not seem to affect the strength of the suture when subjected to loads within physiological ranges.

New Advances in Biomedical Application of Polymeric Micelles.

In the last decade, nanomedicine has arisen as an emergent area of medicine, which studies nanometric systems, namely polymeric micelles (PMs), that increase the solubility and the stability of the encapsulated drugs. Furthermore, their application in dermal drug delivery is also relevant. PMs present unique characteristics because of their unique core-shell architecture. They are colloidal dispersions of amphiphilic compounds, which self-assemble in an aqueous medium, giving a structure-type core-shell, with a hydrophobic core (that can encapsulate hydrophobic drugs), and a hydrophilic shell, which works as a stabilizing agent. These features offer PMs adequate steric protection and determine their hydrophilicity, charge, length, and surface density properties. Furthermore, due to their small size, PMs can be absorbed by the intestinal mucosa with the drug, and they transport the drug in the bloodstream until the therapeutic target. Moreover, PMs improve the pharmacokinetic profile of the encapsulated drug, present high load capacity, and are synthesized by a reproducible, easy, and low-cost method. In silico approaches have been explored to improve the physicochemical properties of PMs. Based on this, a computer-aided strategy was developed and validated to enable the delivery of poorly soluble drugs and established critical physicochemical parameters to maximize drug loading, formulation stability, and tumor exposure. Poly(2-oxazoline) (POx)-based PMs display unprecedented high loading concerning water-insoluble drugs and over 60 drugs have been incorporated in POx PMs. Among various stimuli, pH and temperature are the most widely studied for enhanced drug release at the site of action. Researchers are focusing on dual (pH and temperature) responsive PMs for controlled and improved drug release at the site of action. These dual responsive systems are mainly evaluated for cancer therapy as certain malignancies can cause a slight increase in temperature and a decrease in the extracellular pH around the tumor site. This review is a compilation of updated therapeutic applications of PMs, such as PMs that are based on Pluronics®, micelleplexes and Pox-based PMs in several biomedical applications.

Where Is Nano Today and Where Is It Headed? A Review of Nanomedicine and the Dilemma of Nanotoxicology.

Worldwide nanotechnology development and application have fueled many scientific advances, but technophilic expectations and technophobic demands must be counterbalanced in parallel. Some of the burning issues today are the following: (1) Where is nano today? (2) How good are the communication and investment networks between academia/research and governments? (3) Is there any spotlight application for nanotechnology? Nanomedicine is a particular arm of nanotechnology within the healthcare landscape, focused on diagnosis, treatment, and monitoring of emerging (such as coronavirus disease 2019, COVID-19) and contemporary (including diabetes, cardiovascular diseases, neurodegenerative disorders, and cancer) diseases. However, it may only represent the bright side of the coin. In fact, in the recent past, the concept of nanotoxicology has emerged to address the dark shadows of nanomedicine. The nanomedicine field requires more nanotoxicological studies to identify undesirable effects and guarantee safety. Here, we provide an overall perspective on nanomedicine and nanotoxicology as central pieces of the giant puzzle of nanotechnology. First, the impact of nanotechnology on education and research is highlighted, followed by market trends and scientific output tendencies. In the next section, the nanomedicine and nanotoxicology dilemma is addressed through the interplay of in silico, in vitro, and in vivo models with the support of omics and microfluidic approaches. Lastly, a reflection on the regulatory issues and clinical trials is provided. Finally, some conclusions and future perspectives are proposed for a clearer and safer translation of nanomedicines from the bench to the bedside.

3D printed carboxymethyl cellulose scaffolds for autologous growth factors delivery in wound healing.

This work aims to use carboxymethyl cellulose (CMC) as main structural and functional component of 3D printed scaffolds for healing of diabetic wounds. Differently from previous inks involving small contents in CMC, herein sterile (steam-heated) concentrated CMC solely dispersions (10-20%w/v) were screened regarding printability and fidelity properties. CMC (15%w/v)-citric acid inks showed excellent self-healing rheological properties and stability during storage. CMC scaffolds loaded with platelet rich plasma (PRP) sustained the release of relevant growth factors. CMC scaffolds both with and without PRP promoted angiogenesis in ovo, stem cell migration in vitro, and wound healing in a diabetic model in vivo. Transparent CMC scaffolds allowed direct monitoring of bilateral full-thickness wounds created in rat dorsum. CMC scaffolds facilitated re-epithelialization, granulation, and angiogenesis in full-thickness skin defects, and the performance was improved when combined with PRP. Overall, CMC is pointed out as outstanding component of active dressings for diabetic wounds.

Niosomes-based gene delivery systems for effective transfection of human mesenchymal stem cells.

Gene transfer to mesenchymal stem cells (MSCs) has arisen as a powerful approach to increase the therapeutic potential of this effective cell population. Over recent years, niosomes have emerged as self-assembled carriers with promising performance for gene delivery. The aim of our work was to develop effective niosomes-based DNA delivery platforms for targeting MSCs. Niosomes based on 1,2-di-O-octadecenyl-3-trimethylammonium propane (DOTMA; 0, 7 or 15%) as cationic lipid, cholesterol as helper lipid, and polysorbate 60 as non-ionic surfactant, were prepared using a reverse phase evaporation technique. Niosomes dispersions (filtered or not) and their corresponding nioplexes with a lacZ plasmid were characterized in terms of size, charge, protection, and complexation abilities. DOTMA concentration had a large influence on the physicochemical properties of resulting nioplexes. Transfection efficiency and cytotoxic profiles were assessed in two immortalized cell lines of MSCs. Niosomes formulated with 15% DOTMA provided the highest values of ß-galactosidase activity, being similar to those achieved with Lipofectamine®, but showed less cytotoxicity. Filtration of niosomes dispersions before adding to the cells resulted in a loss of their biological activities. Storage of niosomes formulations (for 30 days at room temperature) caused minor modification of their physicochemical properties but also attenuated the transfection capability of the nioplexes. Differently, addition of the lysosomotropic agent sucrose into the culture medium during transfection or to the formulation itself improved the transfection performance of non-filtered niosomes. Indeed, steam heat-sterilized niosomes prepared in sucrose medium demonstrated transfection capability.

One-step electrospun scaffold of dual-sized gelatin/poly-3-hydroxybutyrate nano/microfibers for skin regeneration in diabetic wound.

This work aimed to implement an electrospinning protocol that allows simultaneous production of micro- and nanofibers in a single scaffold to mimic the extracellular matrix (ECM) combining biodegradable polymers and proteins, and to evaluate its capability to manage diabetic wounds. Poly-3-hydroxybutyrate (PHB) and gelatin (Ge) were chosen to prepare micro- and nanofibers, respectively. Electrospinning conditions were optimized testing various polymer concentrations, voltages, and flow rates. One-step dual-size fibers were obtained from 8%w/v PHB in chloroform (microfibers, 1.25 ± 0.17 µm) and 30%w/v gelatin in acetic acid (75%w/v) (nanofibers, 0.20 ± 0.04 µm), at 0.5 mL/h and 25 kV. A chemical characterization, swelling, hydrophilicity of scaffolds made of PHB-microfibers, Ge-nanofibers and their combination (Ge-PHB) were evaluated before and after crosslinking with genipin. All scaffolds showed excellent fibroblasts viability and attachment after incubation for 1, 3, and 7 days, and low levels of hemolysis. In vivo wound healing was evaluated in diabetic rats for 21 days. Ge-containing scaffolds promoted faster healing. The wounds treated with the Ge-PHB scaffolds proved to be in a late proliferative stage showing higher content of hair follicles and sweat glands and lower content in fibroblast compared with the control wounds.

Hyaluronan/Poly-L-lysine/Berberine Nanogels for Impaired Wound Healing.

Physiological wound healing process can be delayed in the presence of certain pathologies, such as diabetes or cancer. In this perspective, the aim of this study was to design a new nanogel platform of hyaluronan, poly-L-lysine and berberine suitable for wound treatment. Two different nanogel formulations were selected after a first formulation screening. They were prepared by adding dropwise 2 mg/mL hyaluronan aqueous solution (200 or 700 kDa) to 1.25 mg/mL poly-L-lysine aqueous solution. Blank nanogels formulated with 200 kDa HA resulted stable after freeze-drying with dimensions, polydispersity index and zeta potential of 263.6 ± 13.1 nm, 0.323 ± 0.029 and 32.7 ± 3.5 mV, respectively. Both blank and berberine-loaded nanogels showed rounded-shape structures. Loaded nanogels released nearly 50% of loaded berberine within 45 min, whereas the remaining 50% was released up to 24 h in vitro. Both, blank and berberine-loaded nanogels were able to completely close the fibroblasts gap in 42 h.

Micelleplexes as nucleic acid delivery systems for cancer-targeted therapies.

Cancer remains one of the leading causes of death worldwide despite significant therapeutic advancements and improved detection methods. Nucleic acid (NA) therapeutics are receiving increasing attention for cancer management and cure. Indeed, ribonucleic acid (RNA) oligonucleotides (such as small interfering RNA (siRNA) and micro RNA (miRNA)), messenger RNA (mRNA) and deoxyribonucleic acid (DNA) (such as plasmidic DNA (pDNA) and minicircle DNA (mcDNA)), have demonstrated potential as novel therapeutic agents. The imposing prospects of NA-based therapeutics reside in their ability to act as key-players mediating cellular pathways and bestowing potent gene silencing properties, as in the case of RNA interference (RNAi) agents, or by promoting the expression of specific required proteins for disease management (pDNA, mcDNA and mRNA, for instance). However, efficient NA therapeutics delivery is seriously hampered by NA physicochemical features, low in vivo serum stability and compromised cellular internalization, which swiftly reduce their biological activities. Recently, nano-based systems emerged as suitable vehicles for NA delivery. This review covers NA-carrying micelleplexes as robust and multifunctional polymer-based NA delivery systems, as well as the specific in vivo challenges for successful NA delivery to cancer cells and their prospects to become clinical reality, followed by a critical analysis of the major in vivo micelleplex-based cancer-targeted strategies accomplished till the present day.

Polypseudorotaxanes of Pluronic® F127 with Combinations of α- and ß-Cyclodextrins for Topical Formulation of Acyclovir.

Acyclovir (ACV) is one of the most used antiviral drugs for the treatment of herpes simplex virus infections and other relevant mucosal infections caused by viruses. Nevertheless, the low water solubility of ACV limits both its bioavailability and antiviral performance. The combination of block copolymer micelles and cyclodextrins (CDs) may result in polypseudorotaxanes with tunable drug solubilizing and gelling properties. However, the simultaneous addition of various CDs has barely been investigated yet. The aim of this work was to design and characterize ternary combinations of Pluronic® F127 (PF127), αCD and ßCD in terms of polypseudorotaxane formation, rheological behavior, and ACV solubilization ability and controlled release. The formation of polypseudorotaxanes between PF127 and the CDs was confirmed by FT-IR spectroscopy, X-ray diffraction, and NMR spectroscopy. The effects of αCD/ßCD concentration range (0-7% w/w) on copolymer (6.5% w/w) gel features were evaluated at 20 and 37 °C by rheological studies, resulting in changes of the copolymer gelling properties. PF127 with αCD/ßCD improved the solubilization of ACV, maintaining the biocompatibility (hen's egg test on the chorio-allantoic membrane). In addition, the gels were able to sustain acyclovir delivery. The formulation prepared with similar proportions of αCD and ßCD provided a slower and more constant release. The results obtained suggest that the combination of Pluronic with αCD/ßCD mixtures can be a valuable approach to tune the rheological features and drug release profiles from these supramolecular gels.

Controlled Release of rAAV Vectors from APMA-Functionalized Contact Lenses for Corneal Gene Therapy.

As an alternative to eye drops and ocular injections for gene therapy, the aim of this work was to design for the first time hydrogel contact lenses that can act as platforms for the controlled delivery of viral vectors (recombinant adeno-associated virus, rAAV) to the eye in an effective way with improved patient compliance. Hydrogels of hydroxyethyl methacrylate (HEMA) with aminopropyl methacrylamide (APMA) (H1: 40, and H2: 80 mM) or without (Hc: 0 mM) were synthesized, sterilized by steam heat (121 °C, 20 min), and then tested for gene therapy using rAAV vectors to deliver the genes to the cornea. The hydrogels showed adequate light transparency, oxygen permeability, and swelling for use as contact lenses. Loading of viral vectors (rAAV-lacZ, rAAV-RFP, or rAAV-hIGF-I) was carried out at 4 °C to maintain viral vector titer. Release in culture medium was monitored by fluorescence with Cy3-rAAV-lacZ and AAV Titration ELISA. Transduction efficacy was tested through reporter genes lacZ and RFP in human bone marrow derived mesenchymal stem cells (hMSCs). lacZ was detected with X-Gal staining and quantified with Beta-Glo®, and RFP was monitored by fluorescence. The ability of rAAV-hIGF-I-loaded hydrogels to trigger cell proliferation in hMSCs was evaluated by immunohistochemistry. Finally, the ability of rAAV-lacZ-loaded hydrogels to transduce bovine cornea was confirmed through detection with X-Gal staining of ß-galactosidase expressed within the tissue.

Nanomedicine in osteosarcoma therapy: Micelleplexes for delivery of nucleic acids and drugs toward osteosarcoma-targeted therapies.

Osteosarcoma(OS) represents the main cancer affecting bone tissue, and one of the most frequent in children. In this review we discuss the major pathological hallmarks of this pathology, its current therapeutics, new active biomolecules, as well as the nanotechnology outbreak applied to the development of innovative strategies for selective OS targeting. Small RNA molecules play a role as key-regulator molecules capable of orchestrate different responses in what concerns cancer initiation, proliferation, migration and invasiveness. Frequently associated with lung metastasis, new strategies are urgent to upgrade the therapeutic outcomes and the life-expectancy prospects. Hence, the prominent rise of micelleplexes as multifaceted and efficient structures for nucleic acid delivery and selective drug targeting is revisited here with special emphasis on ligand-mediated active targeting. Future landmarks toward the development of novel nanostrategies for both OS diagnosis and OS therapy improvements are also discussed.

Nanotheranostic Pluronic-Like Polymeric Micelles: Shedding Light into the Dark Shadows of Tumors.

Cancer is a leading cause of death worldwide. Despite the advances in prevention, detection, diagnosis, and treatment, many tumors relapse and become resistant to conventional treatments. Theranostics and real-time molecular imaging using nanoscale materials, such as polymeric micelles, are being widely explored as promising gold standard approaches in a personalized medicine perspective for cancer. Theranostics is intended for the three-in-one purpose of simultaneously diagnose, treat, and monitor tumor evolution. Compared to the conventional treatments, theranostic functional polymeric micelles have demonstrated great potential to improve and monitor the delivery of pharmacological agents following administration, which can enhance therapeutic efficacy and minimize off-target toxicity. This review provides an overview of the current state of the art related to the use of polymeric micelles as theranostic multicarriers targeting the cancer cells and tumor microenvironment. Some future directions toward the design of nanotheranostic platforms are also proposed. In particular, we focused our attention on Pluronics and Tetronics as they advantageously present sol-gel transition, which makes them smart nanosystems suitable for oral theranostic administration and sustained depots, increasing patient compliance.

Smart Drug Release from Medical Devices.

Medical devices are becoming key players on health monitoring and treatment. Advances in materials science and electronics have paved the way to the design of advanced wearable, insertable, and implantable medical devices suitable for the prevention and cure of diseases and the physical or functional replacement of damaged tissues or organs. However, intimate and prolonged contact of the medical devices with the human body increases the risks of adverse foreign-body reactions and biofilm formation. Drugs can be included in/on the medical device not only to minimize the risks but also to improve the therapeutic outcomes. Drug-eluting medical devices can deliver the drug in the place where it is needed using lower doses and avoiding systemic effects. Drug-device combination products that release the drug following preestablished rates have already demonstrated their clinical relevance. The aim of this mini-review is to bring attention to medical devices that can actively regulate drug release as a function of tiny changes in their environment, caused by the pathology itself, microorganisms adhesion or some external events. Thus, endowing medical devices with stimuli-responsiveness should allow for precise, on-demand, regulated release of the ancillary drugs to expand the therapeutic performance of the medical device and also should serve as a first step to offer personalized solutions to each patient. Main sections deal with smart drug-eluting medical devices that are sensitive to infection-related stimuli, natural healing processes, mechanical forces, electric fields, ultrasound, near-infrared radiation, or chemicals such as vitamin C.

RNAi-based therapeutics for lung cancer: biomarkers, microRNAs, and nanocarriers.

INTRODUCTION: Despite the current advances in the discovery of the lung cancer biomarkers and, consequently, in the diagnosis, this pathology continues to be the primary cause of cancer-related death worldwide. In most cases, the illness is diagnosed in an advanced stage, which limits the current treatment options available and reduces the survival rate. Therefore, RNAi-based therapy arises as a promising option to treat lung cancer. AREAS COVERED: This review provides an overview on the exploitation of lung cancer biology to develop RNAi-based therapeutics to be applied in the treatment of lung cancer. Furthermore, the review analyzes the main nanocarriers designed to deliver RNAi molecules and induce antitumoral effects in lung cancer, and provides updated information about current RNAi-based therapeutics for lung cancer in clinical trials. EXPERT OPINION: RNAi-based therapy uses nanocarriers to perform a targeted and efficient delivery of therapeutic genes into lung cancer cells, by taking advantage of the known biomarkers in lung cancer. These therapeutic genes are key regulatory molecules of crucial cellular pathways involved in cell proliferation, migration, and apoptosis. Thereby, the characteristics and functionalization of the nanocarrier and the knowledge of lung cancer biology have direct influence in improving the therapeutic effect of this therapy.

Gallic acid loaded PEO-core/zein-shell nanofibers for chemopreventive action on gallbladder cancer cells.

Coaxial electrospinning was used to develop gallic acid (GA) loaded poly(ethylene oxide)/zein nanofibers in order to improve its chemopreventive action on human gallbladder cancer cells. Using a Plackett-Burman design, the effects of poly(ethylene oxide) and zein concentration and applied voltage on the diameter and morphology index of nanofibers were investigated. Coaxial nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). GA loading efficiency as high as 77% was obtained under optimal process conditions. The coaxial nanofibers controlled GA release in acid and neutral pH medium. Cytotoxicity and reactive oxygen species (ROS) production on gallbladder cancer cell lines GB-d1 and NOZ in the presence of GA-nanofibers were assessed. GA-nanofibers triggered an increase in the cellular cytotoxicity compared with free GA on GB-d1 and NOZ cells. Statistically significant differences were found in ROS levels of GA-nanofibers compared with free GA on NOZ cells. Differently, ROS production on GB-d1 cell line was similar. Based on these results, the coaxial nanofibers obtained in this study under optimized operational conditions offer an alternative for the development of a GA release system with improved chemopreventive action on gallbladder cancer cells.

Poloxamer 407/TPGS Mixed Micelles as Promising Carriers for Cyclosporine Ocular Delivery.

Cyclosporine is an immunosuppressant agent approved for the treatment of dry eye disease and used off-label for other ocular pathologies. Its formulation and ocular bioavailability present a real challenge due to the large molecular weight (1.2 kDa), high lipophilicity, and low water solubility. The aim of the work was to develop an aqueous micellar formulation for an efficient cyclosporine delivery to the ocular tissues, using a water-soluble derivative of vitamin E (TPGS: d-α-tocopheryl polyethylene glycol 1000 succinate) and poloxamer 407 (Pluronic ®F127) as excipients. The mixed micelles were characterized in terms of particle size, zeta potential, rheology, and stability upon dilution and freeze-drying. Additionally, the enzymatic-triggered release of vitamin E and vitamin E succinate from TPGS was investigated in vitro in the presence of esterase. Compared to the commercially available ophthalmic formulation, the poloxamer 407:TPGS 1:1 molar ratio micellar formulation significantly improved cyclosporine solubility, which increased proportionally to surfactant concentration reaching 0.4% (w/v) for 20 mM surfactant total concentration. Cyclosporine-loaded mixed micelles efficiently retained the drug once diluted in simulated lachrymal fluid and, in the presence of a 20 mM surfactant concentration, were stable upon freeze-drying. The drug-loaded mixed micelles were applied ex vivo on porcine cornea and compared to Ikervis®. Drug accumulation in the cornea resulted proportional to drug concentration (6.4 ± 1.9, 17.6 ± 5.4, and 26.9 ± 7.4 µgdrug/gcornea, after 3 h for 1, 2.5, and 4 mg/mL cyclosporine concentration respectively). The formulation containing cyclosporine 4 mg/mL (20 mM surfactant) was also evaluated on the sclera, with a view to targeting the posterior segment. The results demonstrated the capability of mixed micelles to diffuse into the sclera and sustain cyclosporine delivery (28 ± 7, 38 ± 10, 57 ± 9, 145 ± 27 µg/cm2 cyclosporine accumulated after 3, 6, 24, and 48 h respectively). Reservoir effect experiments demonstrated that the drug accumulated in the sclera can be slowly released into the underlying tissues. Finally, all the formulations developed in this work successfully passed the HET-CAM assay for the evaluation of ocular irritability.

Mobility of Water and Polymer Species and Rheological Properties of Supramolecular Polypseudorotaxane Gels Suitable for Bone Regeneration.

The aim of this work was to prepare polypseudorotaxane-based supramolecular gels combining αCD with two temperature-responsive copolymers of different architecture (i.e., linear poloxamer P and X-shaped poloxamine T), at the lowest concentration as possible to form syringeable depots, and to shed light on the self-diffusion and spatial closeness of all components (including water) which in turn may determine the cooperative self-assembly phenomena and the performance of the gels at the macroscopic level. The exchange rate between bound water and bulk water was measured with a novel NMR experiment Water Diffusion Exchange-Diffusion Optimized Spectroscopy (WDE-DOSY). Polypseudorotaxane formation caused opposite effects on the mobility of αCD species (decreased) and internal water (increased) but did not affect PPO-water interaction. Consequently, designed ternary P/T/αCD supramolecular gels exhibited in situ gelling at body temperature could host large amounts of PLA/PLGA microspheres and behaved as porous 3D-scaffolds for mesenchymal stem cells (MSCs) supporting their osteogenic differentiation. Interestingly, the gels withstood freeze-drying and reconstitution with minor changes in inner structure and rheological properties. The gathered information may help to understand better the supramolecular gels and provide tools for the rational design of syringeable bone scaffolds that can simultaneously accommodate cells and drug microcarriers for efficient tissue regeneration.