Polymer-Based Nanoparticles with Probucol and Lithocholic Acid: A Novel Therapeutic Approach for Oxidative Stress-Induced Retinopathies.

Oxidative stress is pivotal in retinal disease progression, causing dysfunction in various retinal components. An effective antioxidant, such as probucol (PB), is vital to counteract oxidative stress and emerges as a potential candidate for treating retinal degeneration. However, the challenges associated with delivering lipophilic drugs such as PB to the posterior segment of the eye, specifically targeting photoreceptor cells, necessitate innovative solutions. This study uses formulation-based spray dry encapsulation technology to develop polymer-based PB-lithocholic acid (LCA) nanoparticles and assesses their efficacy in the 661W photoreceptor-like cell line. Incorporating LCA enhances nanoparticles' biological efficacy without compromising PB stability. In vitro studies demonstrate that PB-LCA nanoparticles prevent reactive oxygen species (ROS)-induced oxidative stress by improving cellular viability through the nuclear erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. These findings propose PB-LCA nanoparticles as a promising therapeutic strategy for oxidative stress-induced retinopathies.

Novel Nanoencapsulation Technology and its Potential Role in Bile Acid-Based Targeted Gene Delivery to the Inner Ear.

Hearing loss impacts a large proportion of the global population. Damage to the inner ear, in particular the sensitive hair cells, can impact individuals for the rest of their lives. There are very limited options for interventions after damage to these cells has occurred. Targeted gene delivery may provide an effective means to trigger appropriate differentiation of progenitor cells for effective replacement of these sensitive hair cells. There are several hurdles that need to be overcome to effectively deliver these genes. Nanoencapsulation technology has previously been used for the delivery of pharmaceuticals, proteins and nucleic acids, and may provide an effective means of delivering genes to trigger appropriate differentiation. This review investigates the background of hearing loss, current advancements and pitfalls of gene delivery, and how nanoencapsulation may be useful.

Biguanide Pharmaceutical Formulations and the Applications of Bile Acid-Based Nano Delivery in Chronic Medical Conditions.

Biguanides, particularly the widely prescribed drug metformin, have been marketed for many decades and have well-established absorption profiles. They are commonly administered via the oral route and, despite variation in oral uptake, remain commonly prescribed for diabetes mellitus, typically type 2. Studies over the last decade have focused on the design and development of advanced oral delivery dosage forms using bio nano technologies and novel drug carrier systems. Such studies have demonstrated significantly enhanced delivery and safety of biguanides using nanocapsules. Enhanced delivery and safety have widened the potential applications of biguanides not only in diabetes but also in other disorders. Hence, this review aimed to explore biguanides' pharmacokinetics, pharmacodynamics, and pharmaceutical applications in diabetes, as well as in other disorders.

A second-generation micro/nano capsules of an endogenous primary un-metabolised bile acid, stabilized by Eudragit-alginate complex with antioxidant compounds.

Bile acids (BAs) are amphiphilic compounds and of recently have demonstrated wide range of formulation stabilizing effects. A recent study showed that primary un-metabolised bile acids (PUBAs) have ß-cell protective effects, and synergistic antidiabetic effects when combined with antioxidant and anti-inflammatory drugs, such as probucol (PB). Thus, this study aimed to design and test microcapsules containing a PUBA incorporated with PB and an alginate-Eudragit matrix. Six types of microcapsules were developed without (control) or with (test) PUBA, and tested for internal and external features and ß-cell protective effects. The incorporation of PB-alginate-Eudragit with PUBA produced stable microcapsules but did not exert consistent positive effects on cell viability in the hyperglycaemic state, which suggests that PUBA in alginate-Eudragit matrices did not exhibit synergistic effects with PB nor exerted antidiabetic effects.

Bile acid-polymer-probucol microparticles: protective effect on pancreatic ß-cells and decrease in type 1 diabetes development in a murine model.

Studies in our laboratory have shown potential applications of the anti-atherosclerotic drug probucol (PB) in diabetes due to anti-inflammatory and ß-cell protective effects. The anti-inflammatory effects were optimized by incorporation of the anti-inflammatory bile acid, ursodeoxycholic acid (UDCA). This study aimed to test PB absorption, tissue accumulation profiles, effects on inflammation and type 1 diabetes prevention when combined with UDCA. Balb/c mice were divided into three equal groups and gavaged daily PB powder, PB microcapsules or PB-UDCA microcapsules for one week, at a constant dose. Mice were injected with a single dose of intraperitoneal/subcutaneous alloxan to induce type-1 diabetes and once diabetes was confirmed, treatments were continued for 3 days. Mice were euthanized and blood and tissues collected for analysis of PB and cytokine levels. The PB-UDCA group showed the highest PB concentrations in blood, gut, liver, spleen, brain, and white adipose tissues, with no significant increase in pancreas, heart, skeletal muscles, kidneys, urine or feces. Interferon gamma in plasma was significantly reduced by PB-UDCA suggesting potent anti-inflammatory effects. Blood glucose levels remained similar after treatments, while survival was highest among the PB-UDCA group. Our findings suggest that PB-UDCA resulted in best PB blood and tissue absorption and reduced inflammation.

The effect of deoxycholic acid-based hydrogels on hepatic, muscle and pancreatic beta cells.

Aim: The aim of this study is to test the biocompatibility of hydrogels with polysaccharides and bile acids on three murine cell lines. Materials & methods: Novel hydrogels containing poloxamer 407, polysaccharides (starch, pectin, acacia, carboxymethyl and methyl 2-hydroxyethyl cellulose) and deoxycholic acid were prepared using cold method, sterilized and used in biological assays to determine effects on hepatic, muscle, and pancreatic beta cells. Results and conclusion: Hydrogels with deoxycholic acid had tissue-depending effects on cellular survival and bioenergetics, resulting in the best cellular viability and bioenergetics within pancreatic beta cells. Further research is needed as proposed hydrogels may be beneficial for cell delivery systems of pancreatic beta cells.

In this study, we made gels using different materials, including five types of sugar and an acid found in bile. We investigated whether these gels would harm cells and their respiration. Muscle cells responded poorly to gels, as gels harmed their natural processes. Liver cells responded slightly better to gels, but gels still harmed them a lot. Cells found in the pancreas were not especially affected by gels, and these gels may be good candidates for further research with pancreatic cells. The gels could potentially be used to deliver drugs to the cells.

Biotechnological Effects of Advanced Smart-Bile Acid Cyclodextrin-Based Nanogels for Ear Delivery and Treatment of Hearing Loss.

Inner ear delivery requires safe and effective drug delivery vehicles incorporating high-viscosity formulations with permeation enhancers. This study designs novel thermoresponsive-smart polymer-bile acid and cyclodextrin-based nanogels for inner ear delivery. Nanogels are examined for their rheological and physical properties. The biocompatibility studies will be assessed on auditory and macrophage cell lines by investigating the impact of nanogels on cellular viability, mitochondrial respiration, glycolysis, intracellular oxidative stress, inflammatory profile, and macrophage polarization. Novel ther nanogels based on bile acid and beta-cyclodextrin show preserved porous nanogels' inner structure, exhibit non-Newtonian, shear-thinning fluid behavior, have fast gelation at 37 °C and minimal albumin adsorption on the surface. The nanogels have minimal impact on cellular viability, mitochondrial respiration, glycolysis, intracellular oxidative stress, and inflammatory profile of the auditory cell line House Ear Institute-Organ of Corti 1 after 24 h incubation. Nanogel exposure of 24 h to macrophage cell line RAW264.7 leads to decreased viability, mitochondrial dysfunction, and increased intracellular ROS and inflammatory cytokines. However, polarization changes from M2 anti-inflammatory to M1 pro-inflammatory macrophages are minimal, and inflammatory products of RAW264.7 macrophages do not overly disrupt the survivability of HEI-OC1 cells. Based on these results, thermoresponsive bile acid and cyclodextrin nanogels can be potential drug delivery vehicles for inner ear drug delivery.

Probucol-bile acid nanoparticles: a novel approach and promising solution to prevent cellular oxidative stress in sensorineural hearing loss.

The use of antioxidants could thus prove an effective medication to prevent or facilitate recovery from oxidative stress-induced sensorineural hearing loss (SNHL). One promising strategy to prevent SNHL is developing probucol (PB)-based nanoparticles using encapsulation technology and administering them to the inner ear via the established intratympanic route. The preclinical, clinical and epidemiological studies support that PB is a proven antioxidant that could effectively prevent oxidative stress in different study models. Such findings suggest its applicability in preventing oxidative stress within the inner ear and its associated neural cells. However, several hurdles, such as overcoming the blood-labyrinth barrier, ensuring sustained release, minimising systemic side effects and optimising targeted delivery in the intricate inner ear structures, must be overcome to efficiently deliver PB to the inner ear. This review explores the background and pathogenesis of hearing loss, the potential of PB in treating oxidative stress and its cellular mechanisms, and the obstacles linked to inner ear drug delivery for effectively introducing PB to the inner ear.

Probucol-bile acid based nanoparticles protect auditory cells from oxidative stress: an in vitro study.

Aim: Excessive free radicals contribute to oxidative stress and mitochondrial dysfunction in sensorineural hearing loss (SNHL). The antioxidant probucol holds promise, but its limited bioavailability and inner ear barriers hinder effective SNHL treatment. Methodology: We addressed this by developing probucol-loaded nanoparticles with polymers and lithocholic acid and tested them on House Ear Institute-Organ of Corti cells. Results: Probucol-based nanoparticles effectively reduced oxidative stress-induced apoptosis, enhanced cellular viability, improved probucol uptake and promoted mitochondrial function. Additionally, they demonstrated the capacity to reduce reactive oxygen species through the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 pathway. Conclusion: This innovative nanoparticle system holds the potential to prevent oxidative stress-related hearing impairment, providing an effective solution for SNHL.

Hearing loss affects millions of people worldwide, and its prevalence is expected to double by 2050. Current treatments have limitations, pushing researchers to explore new options. Oxidative stress is a key player in hearing loss and is known to damage inner ear hair cells. While antioxidants, known for their protective effects, hold promise, delivering them effectively to the inner ear is challenging. Scientists have been testing nanoparticles loaded with the antioxidant probucol to fight hearing loss. In this study, these particles protected inner ear cells in cell studies, offering potential hope for preventing hearing problems. This research is a significant step toward finding better treatments for hearing loss.

Probucol-Ursodeoxycholic Acid Otic Formulations: Stability and In Vitro Assessments for Hearing Loss Treatment.

Targeted drug delivery is an ongoing aspect of scientific research that is expanding through the design of micro- and nanoparticles. In this paper, we focus on spray dried microparticles as carriers for a repurposed lipophilic antioxidant (probucol). We characterise the microparticles and quantify probucol prior to assessing cytotoxicity on both control and cisplatin treated hair cells (known as House Ear Institute-Organ of Corti 1; HEI-OC1). The addition of water-soluble polymers to 2% ß-cyclodextrin resulted in a stable probucol formulation. Ursodeoxycholic acid (UDCA) used as formulation excipient increases probucol miscibility and microparticle drug content. Formulation characterisations reveals spray drying results in spherical UDCA-drug microparticles with a mean size distribution of ∼5-12 µm. Probucol microparticles show stable short-term storage conditions accounting for only ∼10% loss over seven days. By mimicking cell culture conditions, both UDCA-probucol (67%) and probucol only (82%) microparticles show drug release in the initial two hours. Furthermore, probucol formulations with or without UDCA preserve cell viability and reduce cisplatin-induced oxidative stress. Mitochondrial bioenergetics results in lower basal respiration and non-mitochondrial respiration, with higher maximal respiration, spare capacity, ATP production and proton leak within cisplatin challenged UDCA-probucol groups. Overall, we present a facile method for incorporating lipophilic antioxidant carriers in polymer-based particles that are tolerated by HEI-OC1 cells and show stable drug release, sufficient in reducing cisplatin-induced reactive oxygen species accumulation.

Polymer-Based Nanoparticles for Inner Ear Targeted Trans Differentiation Gene Therapy.

Hearing loss is a significant disability that often goes under recognised, largely due to poor identification, prevention, and treatment. Steps are being made to amend these pitfalls in the investigation of hearing loss, however, the development of a cure to reverse advanced forms remains distant. This review details some current advances in the treatment of hearing loss, with a particular focus on genetic-based nanotechnology and how it may provide a useful avenue for further research. This review presents a broad background on the pathophysiology of hearing loss and some current interventions. We also highlight some potential genes that may be useful in the amelioration of hearing loss. Pathways of cellular differentiation from stem or supporting cell to functional hair cell are covered in detail, as this mechanism represents a key means of regenerating these cell types. Overall, we believe that polymer-based nanotechnology coupled with novel excipients represents a useful area of further research in the treatment of hearing loss, although further studies in this area are required.

Bile Acid Application in Cell-Targeting for Molecular Receptors in Relation to Hearing: A Comprehensive Review.

Bile acids play important roles in the human body, and changes in their pool can be used as markers for various liver pathologies. In addition to their functional effects in modulating inflammatory responses and cellular survivability, the unconjugated or conjugated, secondary, or primary nature of bile acids accounts for their various ligand effects. The common hydrophilic bile acids have been used successfully as local treatment to resolve drug-induced cell damage or to ameliorate hearing loss. From various literature references, bile acids show concentration and tissue-dependent effects. Some hydrophobic bile acids act as ligands modulating vitamin D receptors, muscarinic receptors, and calcium-activated potassium channels, important proteins in the inner ear system. Currently, there are limited resources investigating the therapeutic effects of bile acid on hearing loss and little to no information on detecting bile acids in the remote ear system, let alone baseline bile acid levels and their prevalence in healthy and disease conditions. This review presents both hydrophilic and hydrophobic human bile acids and their tissue-specific effects in modulating cellular integrity, thus considering the possible effects and extended therapeutic applicability of bile acids to the inner ear tissue.

Novel polysaccharides-bile acid-cyclodextrin gel systems and effects on cellular viability and bioenergetic parameters.

Aim: The novel hydrogel systems made from sodium alginate, pectin, beta-cyclodextrin and deoxycholic acid (DCA) were proposed as potential drug-delivery matrices. Materials & methods: To ensure biocompatibility, rheological parameters were examined and hydrogels' effects on bioenergetic parameters and cellular viability on murine hepatic, and muscle and pancreatic beta cells. Results & conclusion: All hydrogels show non-Newtonian, shear thinning behavior. Cells displayed various oxygen-dependent viability patterns, with the bile acid overall adversely affecting their biological activities. All cells performed best under normoxia, with pancreatic beta cells displaying the most profound oxygen-dependent viability behavior. The cells tolerated the addition of a moderate concentration of beta-cyclodextrin to the polymer matrix.

Potentials and limitations of pharmaceutical and pharmacological applications of bile acids in hearing loss treatment.

Hearing loss is a worldwide epidemic, with approximately 1.5 billion people currently struggling with hearing-related conditions. Currently, the most wildly used and effective treatments for hearing loss are primarily focus on the use of hearing aids and cochlear implants. However, these have many limitations, highlighting the importance of developing a pharmacological solution that may be used to overcome barriers associated with such devices. Due to the challenges of delivering therapeutic agents to the inner ear, bile acids are being explored as potential drug excipients and permeation enhancers. This review, therefore, aims to explore the pathophysiology of hearing loss, the challenges in treatment and the manners in which bile acids could potentially aid in overcoming these challenges.

Influence of poly-L-ornithine-bile acid nano hydrogels on cellular bioactivity and potential pharmacological applications.

Aim: Cellular bioactivity and pathophysiological changes associated with chronic disorders are considered pivotal detrimental factors when developing novel formulations for biomedical applications. Methods: This paper investigates the use of bile acids and synthetic polypeptide poly-L-ornithine (PLO) in formulations and their impacts on a variety of cell lines, with a particular focus on their cellular bioactivity. Results: The hepatic cell line was the most negatively affected by the presence of PLO, while the muscle and beta-pancreatic cell lines did not show as profound of a negative impact of PLO on cellular viability. PLO was the least disruptive regarding mitochondrial function for muscle and beta cells. Conclusion: The addition of bile acids generally decreased mitochondrial respiration and altered bioenergetic parameters in all cell lines.

In our study, we made special gels using two kinds of materials and different acids found in bile. We wanted to see how these gels affected different cells like muscles, liver and pancreatic beta cells. The gels we made had good traits needed for injections. Liver cells didn't enjoy the new materials very much. Adding bile acids to the materials changed how the cells acted for all cell types we looked at.

The biocompatibility and the metabolic impact of thermoresponsive, bile acid-based nanogels on auditory and macrophage cell lines.

Deoxycholic acid (DCA), lithocholic acid (LCA), and ursodeoxycholic acid (UDCA) are bile acids that may serve as permeation enhancers when incorporated within the nanogel matrix for drug delivery in the inner ear. In this study, thermoresponsive nanogels were formulated with DCA, LCA and UDCA and their rheological properties and biocompatibility were assessed. The impact of nanogel on cellular viability was evaluated via cell viability assay, the impact of nanogels on cellular bioenergetic parameters was estimated by Seahorse mito-stress test and glycolysis-stress test, while the presence of intracellular free radicals was assessed by reactive oxygen species assay. Nanogels showed a high level of biocompatibility after 24-hour exposure to auditory and macrophage cell lines, with minimal cytotoxicity compared to untreated control. Incubation with nanogels did not alter cellular respiration and glycolysis of the auditory cell line but showed possible mitochondrial dysfunction in macrophages, suggesting tissue-dependent effects of bile acids. Bile acid-nanogels had minimal impact on intracellular reactive oxygen species, with LCA demonstrating the most pro-oxidative behaviour. This study suggests that thermoresponsive nanogels with bile acid, particularly DCA and UDCA, may be promising candidates for inner ear drug delivery.

The applications of targeted delivery for gene therapies in hearing loss.

Gene therapies are becoming more abundantly researched for use in a multitude of potential treatments, including for hearing loss. Hearing loss is a condition which impacts an increasing number of the population each year, with significant burdens associated. As such, this review will present the concept that delivering a gene effectively to the inner ear may assist in expanding novel treatment options and improving patient outcomes. Historically, several drawbacks have been associated with the use of gene therapies, some of which may be overcome via targeted delivery. Targeted delivery has the potential to alleviate off-target effects and permit a safer delivery profile. Viral vectors have often been described as a delivery method, however, there is an emerging depiction of the potential for nanotechnology to be used. Resulting nanoparticles may also be tuned to allow for targeted delivery. Therefore, this review will focus on hearing loss, gene delivery techniques and inner ear targets, including highlighting promising research. Targeted delivery is a key concept to permitting gene delivery in a safe effective manner, however, further research is required, both in the determination of genes to use in functional hearing recovery and formulating nanoparticles for targeted delivery.

Poly-L-lysine as a crosslinker in bile acid and alginate nanoaggregates for gene delivery in auditory cells.

Background: Hearing loss is a condition that may affect a wide array of patients from various backgrounds. There are no cures for sensorineural hearing loss. Gene therapy is one possible method of improving hearing status; however, gene delivery remains challenging. Materials & methods: Polymer nanoaggregates of alginate and poly-L-lysine were prepared with and without bile acid. The nanoaggregates had physical properties, cytotoxicity, gene release and gene expression analyzed. Results & discussion: The nanoparticles produced had appropriate size and charge, low cytotoxicity between 0.5 and 1.0 mg/ml and linear gene release but poor transfection efficiency. Conclusion: The present study provides preliminary evidence for the efficacy of polymer nanotechnology with bile acids for inner ear gene delivery; optimization is required to improve transfection efficiency.

Hearing loss is a global issue with significant consequences. Gene therapy is an emerging technique in the management of various conditions, including hearing loss. This involves the delivery of a new copy of a gene to a cell with a missing or defective copy of that gene. The delivery of genes such as ATOH1 has been shown to encourage cell differentiation into new functional hair cells to potentially reverse hearing loss. Unfortunately, effective and safe delivery of genes remains challenging. Polymer nanoparticles represent one method for delivering genes that allows for customizability in size, structure and function. In this study, the authors developed nanoparticles with a polymer derived from algae called alginate, an amino acid polymer called poly-L-lysine and bile acid to improve gene delivery to inner ear cells. A cell line derived from the inner ear of a mouse was used to test the effectiveness of these particles at delivering genes. A gene that makes cells that uptake these particles fluoresce was included in the nanoparticles, to demonstrate they are capable of gene delivery. In the future, this gene could be replaced with genes associated with encouraging cell differentiation. The preliminary results of this study suggest that such nanoparticles may be capable of gene delivery, although further optimization is required.

Pharmaceutical characterization of probucol bile acid-lithocholic acid nanoparticles to prevent chronic hearing related and similar cellular oxidative stress pathologies.

Background: Sensorineural hearing loss has been associated with oxidative stress. However, an antioxidant that passes effectively through the ear remains elusive. Method: Probucol (PB)-based nanoparticles were formed using a spray-drying encapsulation technique, characterized and tested in vitro. Results: Uniform, spherical nanoparticles were produced. The addition of lithocholic acid to PB formulations did not affect drug content or production yield, but it did modify capsule size, surface tension, electrokinetic stability and drug release. Cell viability, bioenergetics and inflammatory profiles were improved when auditory cells were exposed to PB-based nanoparticles, which showed antioxidant properties (p < 0.05). Conclusion: PB-based nanoparticles can potentially protect the auditory cell line from oxidative stress and could be used in future in vivo studies as a potential new therapeutic agent for sensorineural hearing loss.

Oxidative stress is an imbalance of cellular processes in which the production of free radicals outweighs the cellular defense mechanism. The association of oxidative stress with the pathophysiology of sensorineural hearing loss (SHL) is well established. SHL development is associated with chronic damage in the structure of the inner ear or auditory nerve. Therefore, potent antioxidants such as probucol could be one way to prevent or treat SHL. However, due to its isolated position, SHL is challenging to treat, imposing a desperate need for refining existing therapeutic methods; one way to do this is by optimizing the formulation using nanoparticles. We aimed to design a novel, stable formulation of PB using polymers and excipients to develop nanoparticles and examine the efficiency of these formulations on the HEI-OC1 stress cell line. We found that the prepared nanoparticle is robust and stable and protects HEI-OC1 from cellular toxicity and oxidative stress. It could be a novel therapeutic agent to treat or prevent SHL.

Novel hydrogel comprising non-ionic copolymer with various concentrations of pharmacologically active bile acids for cellular injectable gel.

Deoxycholic acid (DCA) is a bile acid capable of forming micelles and modifying the properties of hydrogels. We incorporated DCA in sodium alginate (SA) and poloxamer 407 matrices creating novel DCA-copolymer hydrogel for therapeutic delivery. Hydrogels were assessed for common rheological properties. Biocompatibility and biological effect were examined on various cell lines. Cell viability was determent in normal and various hypoxic conditions, and full mitochondrial bioenergetic parameters were assessed in cell lines in order to illustrate hydrogel effects on survival, and cell metabolic profile within the hydrogels. Obtained data suggest that a low dose of DCA in permeable, biocompatible hydrogels can be beneficial for cells to combat hypoxic conditions.