Nanostructured lipid carrier-based smart gel: a delivery platform for intra-articular therapeutics

Advances in local drug delivery technologies for improved rheumatoid arthritis therapy

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by an inflammatory microenvironment and cartilage erosion within the joint cavity. Currently, antirheumatic agents yield significant outcomes in RA treatment. However, their systemic administration is limited by inadequate drug retention in lesion areas and non-specific tissue distribution, reducing efficacy and increasing risks such as infection due to systemic immunosuppression. Development in local drug delivery technologies, such as nanostructure-based and scaffold-assisted delivery platforms, facilitate enhanced drug accumulation at the target site, controlled drug release, extended duration of the drug action, reduced both dosage and administration frequency, and ultimately improve therapeutic outcomes with minimized damage to healthy tissues. In this review, we introduced pathogenesis and clinically used therapeutic agents for RA, comprehensively summarized locally administered nanostructure-based and scaffold-assisted drug delivery systems, aiming at improving the therapeutic efficiency of RA by alleviating the inflammatory response, preventing bone erosion and promoting cartilage regeneration. In addition, the challenges and future prospects of local delivery for clinical translation in RA are discussed.

In situ hydrogel containing diazepam-loaded nanostructured lipid carriers (DZP-NLC) for nose-to-brain delivery: development, characterization and deposition studies in a 3D-printed human nasal cavity model

The nasal route has been investigated as a promising alternative for drug delivery to the central nervous system, avoiding passage through the blood-brain barrier and improving bioavailability. In this sense, it is necessary to develop and test the effectiveness of new formulations proposed for the management of neurological disorders. Thereby, the aim of this work was to develop and characterize an ion sensitive in situ hydrogel containing diazepam-loaded nanostructured lipid carriers (DZP-NLC) for nasal delivery in the treatment of epilepsy. Physical characterization of the developed formulations was performed and included the evaluation of rheological features, particle size, polydispersity index (PDI) and zeta potential (ZP) of an in situ hydrogel containing DZP-NLC. Afterwards, in vitro drug release, in vitro mucoadhesion and biocompatibility studies with RPMI 2650 nasal cells were performed. The in situ hydrogel containing DZP-NLC was aerosolized with a nasal spray device specifically designed for nose-to-brain delivery (VP7 multidose spray pump with a 232 N2B actuator) and characterized for droplet size distribution and spray cone angle. Finally, the deposition pattern of this hydrogel was evaluated in a 3D-printed human nasal cavity model. The developed in situ hydrogel containing DZP-NLC presented adequate characteristics for nasal administration, including good gelling ability, mucoadhesiveness and prolonged drug release. In addition, after inclusion in the hydrogel net, the particle size (81.79 ± 0.53 nm), PDI (0.21 ± 0.10) and ZP (-30.90 ± 0.10 mV), of the DZP-NLC remained appropriate for nose-to-brain delivery. Upon aerosolization in a nasal spray device, a suitable spray cone angle (22.5 ± 0.2°) and adequate droplet size distribution (Dv (90) of 317.77 ± 44.12 µm) were observed. Biocompatibility studies have shown that the developed formulation is safe towards RPMI 2650 cells in concentrations up to 100 μg/mL. Deposition studies on a 3D-printed human nasal cavity model revealed that the best nasal deposition profile was obtained upon formulation administration without airflow and at an angle from horizontal plane of 75°, resulting in 47% of administered dose deposited in the olfactory region and 89% recovery. The results of this study suggested that the intranasal administration of the developed in situ hydrogel containing DZP-NLC could be a promising alternative to the conventional treatments for epilepsy.

Thermosensitive In Situ Gels for Joint Disorders: Pharmaceutical Considerations in Intra-Articular Delivery

The intra-articular administration of conventional drug solutions or dispersions in joint diseases such as osteoarthritis has a relatively short retention time and, therefore, limited therapeutic effect. Thermosensitive polymer solutions that exhibit a sol-gel phase transition near body temperature after injection can prolong drug retention by providing a depot from which the drug release is sustained while relieving inflammation and preventing degradation of the joint complex. Thermosensitive hydrogels have in recent times garnered considerable attention in the intra-articular therapeutics of joint diseases such as osteoarthritis. Among the stimuli-responsive gelling systems, most research has focused on thermosensitive hydrogels. These gels are preferred over other stimuli-sensitive hydrogels since they have well-controlled in situ gelling properties and are also easier to load with drugs. Temperature-sensitive polymers, such as block copolymers or poloxamers, are frequently used to modify their gelation properties, usually in combination with other polymers. They are compatible with most drugs but may pose formulation challenges in terms of their low-response time, highly fragile nature, and low biocompatibility. The stability and biodegradability of implant hydrogels can control the drug release rate and treatment efficacy. This review stresses the application of thermosensitive gels in joint disorders and summarizes recent developments for intra-articular application, including the incorporation of nanoparticles. The hydrogel composition, drug release mechanisms, and the challenges involved in their formulation and storage are also discussed.

Curcumin-based nanotechnology approaches and therapeutics in restoration of autoimmune diseases

Autoimmune diseases usually arise as a result of an aberrant immune system attack on normal tissues of the body, which leads to a cascade of inflammatory reactions. The immune system employs different types of protective and anti-inflammatory cells for the regulation of this process. Curcumin is a known natural anti-inflammatory agent that inhibits pathological autoimmune processes by regulating inflammatory cytokines and their associated signaling pathways in immune cells. Due to the unstable nature of curcumin and its susceptibility to either degradation, or metabolism into other chemical entities (i.e., metabolites), encapsulation of this agent into various nanocarriers would appear to be an appropriate strategy for attaining greater beneficial effects from curcumin as it pertains to immunomodulation. Many studies have focused on the design and development of curcumin nanodelivery systems (micelles, dendrimers, and diverse nanocarriers) and are summarized in this review in order to obtain greater insight into novel drug delivery systems for curcumin and their suitability for the management of autoimmune diseases.

An Innovative Formulation Based on Nanostructured Lipid Carriers for Imatinib Delivery: Pre-Formulation, Cellular Uptake and Cytotoxicity Studies

Imatinib (IMT) is a tyrosine kinase enzyme inhibitor and extensively used for the treatment of gastrointestinal stromal tumors (GISTs). A nanostructured lipid carrier system (NLCS) containing IMT was developed by using emulsification-sonication methods. The characterization of the developed formulation was performed in terms of its particle size, polydispersity index (PDI), zeta potential, entrapment efficiency, loading capacity, sterility, syringeability, stability, in vitro release kinetics with mathematical models, cellular uptake studies with flow cytometry, fluorescence microscopy and cytotoxicity for CRL-1739 cells. The particle size, PDI, loading capacity and zeta potential of selected NLCS (F16-IMT) were found to be 96.63 ± 1.87 nm, 0.27 ± 0.15, 96.49 ± 1.46% and -32.7 ± 2.48 mV, respectively. F16-IMT was found to be stable, thermodynamic, sterile and syringeable through an 18 gauze needle. The formulation revealed a Korsmeyer-Peppas drug release model of 53% at 8 h, above 90% of cell viability, 23.61 µM of IC50 and induction of apoptosis in CRL-1739 cell lines. In the future, F16-IMT can be employed to treat GISTs. A small amount of IMT loaded into the NLCSs will be better than IMT alone for therapy for GISTs. Consequently, F16-IMT could prove to be useful for effective GIST treatment.