Nanoparticle-encapsulated P2X7 receptor antagonist in a pH-sensitive polymer as a potential local drug delivery system to acidic inflammatory environments

Inflammation-responsive drug delivery nanosystems for treatment of bacterial-induced sepsis

Sepsis, a complication of dysregulated host immune systemic response to an infection, is life threatening and causes multiple organ injuries. Sepsis is recognized by WHO as a big contributor to global morbidity and mortality. The heterogeneity in sepsis pathophysiology, antimicrobial resistance threat, the slowdown in the development of antimicrobials, and limitations of conventional dosage forms jeopardize the treatment of sepsis. Drug delivery nanosystems are promising tools to overcome some of these challenges. Among the drug delivery nanosystems, inflammation-responsive nanosystems have attracted considerable interest in sepsis treatment due to their ability to respond to specific stimuli in the sepsis microenvironment to release their payload in a precise, targeted, controlled, and rapid manner compared to non-responsive nanosystems. These nanosystems posit superior therapeutic potential to enhance sepsis treatment. This review critically evaluates the recent advances in the design of drug delivery nanosystems that are inflammation responsive and their potential in enhancing sepsis treatment. The sepsis microenvironment's unique features, such as acidic pH, upregulated receptors, overexpressed enzymes, and enhanced oxidative stress, that form the basis for their design have been adequately discussed. These inflammation-responsive nanosystems have been organized into five classes namely: Receptor-targeted nanosystems, pH-responsive nanosystems, redox-responsive nanosystems, enzyme-responsive nanosystems, and multi-responsive nanosystems. Studies under each class have been thematically grouped and discussed with an emphasis on the polymers used in their design, nanocarriers, key characterization, loaded actives, and key findings on drug release and therapeutic efficacy. Further, this information is concisely summarized into tables and supplemented by inserted figures. Additionally, this review adeptly points out the strengths and limitations of the studies and identifies research avenues that need to be explored. Finally, the challenges and future perspectives on these nanosystems have been thoughtfully highlighted.

Inflammatory microenvironment-targeted nanotherapies

Inflammatory microenvironments (IMEs) are common pathological characteristics and drive the development of multiple chronic diseases. Thus, IME-targeted therapies exhibit potential for the treatment of inflammatory diseases. Nanoplatforms have significant advantages in improving the efficiency of anti-inflammatory treatments. Owing to their improved therapeutic effects and reduced side effects, IME-targeted nanotherapies have recently drawn interest from the research community. This review introduces IMEs and discusses the application of IME-targeted nanotherapies for inflammatory diseases. The development of rational targeting strategies tailored to IMEs in damaged tissues can help promote therapies for chronic diseases.

Bioresponsive drug delivery systems for the treatment of inflammatory diseases

Inflammation is intimately related to the pathogenesis of numerous acute and chronic diseases like cardiovascular disease, inflammatory bowel disease, rheumatoid arthritis, and neurodegenerative diseases. Therefore anti-inflammatory therapy is a very promising strategy for the prevention and treatment of these inflammatory diseases. To overcome the shortcomings of existing anti-inflammatory agents and their traditional formulations, such as nonspecific tissue distribution and uncontrolled drug release, bioresponsive drug delivery systems have received much attention in recent years. In this review, we first provide a brief introduction of the pathogenesis of inflammation, with an emphasis on representative inflammatory cells and mediators in inflammatory microenvironments that serve as pathological fundamentals for rational design of bioresponsive carriers. Then we discuss different materials and delivery systems responsive to inflammation-associated biochemical signals, such as pH, reactive oxygen species, and specific enzymes. Also, applications of various bioresponsive drug delivery systems in the treatment of typical acute and chronic inflammatory diseases are described. Finally, crucial challenges in the future development and clinical translation of bioresponsive anti-inflammatory drug delivery systems are highlighted.

Propolis-based niosomes as oromuco-adhesive films: A randomized clinical trial of a therapeutic drug delivery platform for the treatment of oral recurrent aphthous ulcers

Oromuco-adhesive films for buccal delivery of Propolis extract (PPE) entrapped in niosomes, were prepared to treat oral recurrent aphthous ulcer (RAU). PPE was investigated for antimicrobial compounds. Niosomes composed of span60 and cholesterol were evaluated for particles size, polydispersity index (PDI), zeta-potential, entrapment efficiency and in vitro release. The formed oromuco-adhesive films containing niosomal PPE were evaluated for swelling, mucoadhesion and elasticity. 24 patients suffering from RAU were divided equally into medicated and placebo groups and participated in this study to examine the onset of ulcer size reduction, complete healing and pain relief. Ultra-performance liquid chromatography-high resolution mass spectrometry revealed the presence of pinocembrin, pinobanksin, chrysin and galangin as antimicrobial flavonoids with total content of 158.7 ± 0.15 µg quercetin equivalents and phenolic content of 180.8 ± 0.11 µg gallic acid equivalents/mg. Multilamellar niosomes of 176-333 nm displayed entrapment efficiency of 91 ± 0.48%, PDI of 0.676 and zeta potential of -4.99. In vitro release after 8 h from niosomal dispersion and films were 64.05% and 29.09 ± 0.13% respectively. Clinical results revealed duration of film adherence from 2-4 h in the two groups. The onset of ulcer size reduction in medicated group was attained within second and third day, complete healing was achieved within first 10 days of treatment and pain relief lasted for more than 4-5 h, in contrast to the placebo group. This oromuco-adhesive films which offer controlled and targeting drug delivery can be proposed as a new therapeutic strategy in the treatment of oral recurrent aphthous ulcer.

DOE Optimization of Nano-based Carrier of Pregabalin as Hydrogel: New Therapeutic &Chemometric Approaches for Controlled Drug Delivery Systems

Niosomes entrapping pregabalin (PG) were prepared using span 60 and cholesterol in different molar ratios by hydration method, the remaining PG from the hydrating solution was separated from vesicles by freeze centrifugation. Optimization of nano-based carrier of pregabalin (PG) was achieved. Quality by Design strategy was successfully employed to obtain PG-loaded niosomes with the desired properties. The optimal particle size, drug release and entrapment efficiency were attained by Minitab® program using design of experiment (DOE) that predicted the best parameters by investigating the combined effect of different factors simultaneously. Pareto chart was used in the screening step to exclude the insignificant variables while response surface methodology (RSM) was used in the optimization step to study the significant factors. Best formula was selected to prepare topical hydrogels loaded with niosomal PG using HPMC and Carbopol 934. It was verified, by means of mechanical and rheological tests, that addition of the vesicles to the gel matrix affected significantly gel network. In vitro release and ex vivo permeation experiments were carried out. Delivery of PG molecules followed a Higuchi, non Fickian diffusion. The present work will be of interest for pharmaceutical industry as a controlled transdermal alternative to the conventional oral route.

Novel self-assembled pH-responsive biomimetic nanocarriers for drug delivery

Novel pH-responsive biodegradable biomimetic nanocarriers were prepared by the self-assembly of N-acetyl-l-histidine-phosphorylcholine-chitosan conjugate (NAcHis-PCCs), which was synthesized via Atherton-Todd reaction to couple biomembrane-like phosphorylcholine (PC) groups, and N,N'-carbonyldiimidazole (CDI) coupling reaction to link pH-responsive N-acetyl-l-histidine (NAcHis) moieties to chitosan. In vitro biological assay revealed that NAcHis-PCCs nanoparticles had excellent biocompatibility to avoid adverse biological response mainly owing to their biomimetic PC shell, and DLS results confirmed their pH-responsive behavior in acidic aqueous solution (pH≤6.0). Quercetin (QUE), an anti-inflammatory, antioxidant and potential anti-tumor hydrophobic drug, was effectively loaded in NAcHis-PCCs nanocarriers and showed a pH-triggered release behavior with the enhanced QUE release at acidic pH5.5 compared to neutral pH7.4. The results indicated that pH-responsive biomimetic NAcHis-PCCs nanocarriers might have great potential for site-specific delivery to pathological acidic microenvironment avoiding unfavorable biological response.