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.

Bile acids as novel enhancers of CNS targeting antitumor drugs: a comprehensive review.

Despite a relatively low prevalence of primary brain tumors, they continuously attract scientific interest because of the complexity of their treatment due to their location behind the blood-brain barrier. The main challenge in treatment of brain tumors is not the efficacy of the drugs, per se, but the low efficiency of drug delivery to malignant cells. At the core of the problem is the complex structure of the blood-brain barrier. Nowadays, there is evidence supporting the claim that bile acids have the ability to cross the blood-brain barrier. That ability can be exploited by taking a part in novel drug carrier designs. Bile acids represent a drug carrier system as a part of a mixed micelle composition, bilosomes and conjugates with various drugs. This review discusses the current knowledge related to bile acid molecules as drug penetration modifying agents, with the focus on central nervous system antitumor drug delivery.

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 molecular weights of microencapsulating polymers on viability of mouse-cloned pancreatic ß-cells: biomaterials, osmotic forces and potential applications in diabetes treatment.

INTRODUCTION: Ideal cell-containing microcapsules should be capable of maintaining cell viability and exhibit significant structural stability to support cellular functionality. To date, such microcapsules remain unavailable; thus, this study used our well-established microencapsulating methods to examine a total of 32 different microencapsulating formulations and correlate polymers' molecular weights (Mwt) and UDCA addition, with cell viability and microcapsules' stability, postmicroencapsulation. METHODS: MIN6 mouse-cloned pancreatic ß-cells were microencapsulated using control (n = 16; without UDCA) and test (n = 16; with UDCA) different polymers. Confocal microscopic imaging, cell viability, and microcapsules' stability were assessed. RESULTS: Best cell viability (>50%) was obtained at average Mwt of 50,000 g/mol (poly-l-ornithine), followed by 110,000 g/mol (poly-l-lysine). There was no linear correlation between Mwt and viability. Confocal imagining showed similar microcapsules' shape and cell distribution among all different polymers' molecular weights, which suggests that the microencapsulating method was efficient and maintained microcapsules' uniformity. UDCA addition resulted in enhanced osmotic stability of the microcapsules and improved cell viability, when the formulation contained 1% polylornithine, 1% polyethylene glycol, 20% Eudragit® NM30D, 1% polytetrafluoroethylene, or 5% pentamethylcyclopentasiloxane. CONCLUSIONS: UDCA addition improved microenvironmental conditions within the microcapsules but this effect was largely dependent on the polymer systems used.

New Biotechnological Microencapsulating Methodology Utilizing Individualized Gradient-Screened Jet Laminar Flow Techniques for Pancreatic ß-Cell Delivery: Bile Acids Support Cell Energy-Generating Mechanisms.

In previous studies, we developed a new technique (ionic gelation vibrational jet flow; IGVJF) in order to encapsulate pancreatic ß-cells, for insulin in vivo delivery, and diabetes treatment. The fabricated microcapsules showed good morphology but limited cell functions. Thus, this study aimed to optimize the IGVJF technique, by utilizing integrated electrode tension, coupled with high internal vibration, jet-flow polymer stream rate, ionic bath-gelation concentrations, and gelation time stay. The study also utilized double inner/outer nozzle segmented-ingredient flow of microencapsulating dispersion, in order to form ß-cell microcapsules. Furthermore, a microcapsule-stabilizing bile acid was added, and microcapsule's stability and cell functions measured. Buchi-based built-in system utilizing IGVJF technology was screened to produce best microcapsule-containing ß-cells with or without a stabilizing-enhancing bile acid. Formed microcapsules were examined, for physical characteristics, and encapsulated cells were examined for survival, insulin release, and inflammatory profiles. Optimized microencapsulating parameters, using IGJVF, were: 1000 V voltage, 2500 Hz frequency, 1 mL/min flow rate, 3% w/v ionic-bath gelation concentration, and 20 min gelation time. Microcapsules showed good morphology and stability, and the encapsulated cells showed good survival, and insulin secretion, which was optimized by the bile acid. Deployed IGVJF-based microencapsulating parameters utilizing stability-enhancing bile acid produced best microcapsules with best pancreatic ß-cells functions and survival rate, which, suggests potential application in cell transplantation.

Innovative Microcapsules for Pancreatic ß-Cells Harvested from Mature Double-Transgenic Mice: Cell Imaging, Viability, Induced Glucose-Stimulated Insulin Measurements and Proinflammatory Cytokines Analysis.

PURPOSE: Recently we demonstrated that microencapsulation of a murine pancreatic ß-cell line using an alginate-ursodeoxycholic acid (UDCA) matrix produced microcapsules with good stability and cell viability. In this study, we investigated if translation of this formulation to microencapsulation of primary ß-cells harvested from mature double-transgenic healthy mice would also generate stable microcapsules with good cell viability. METHODS: Islets of Langerhans were isolated from Ngn3-GFP/RIP-DsRED mice by intraductal collagenase P digestion and density gradient centrifugation, dissociated into single cells and the ß-cell population purified by Fluorescence Activated Cell Sorting. ß-cells were microencapsulated using either alginate-poly-l-ornithine (F1; control) or alginate-poly-l-ornithine-UDCA (F2; test) formulations. Microcapsules were microscopically examined and microencapsulated cells were analyzed for viability, insulin and cytokine release, 2 days post-microencapsulation. RESULTS: Microcapsules showed good uniformity and morphological characteristics and even cell distribution within microcapsules with or without UDCA. Two days post microencapsulation cell viability, mitochondrial ATP and insulin production were shown to be optimized in the presence of UDCA whilst production of the proinflammatory cytokine IL-1ß was reduced. Contradictory to our previous studies, UDCA did not reduce production of any other pro-inflammatory biomarkers. CONCLUSIONS: These results suggest that UDCA incorporation improves microcapsules' physical and morphological characteristics and improves the viability and function of encapsulated mature primary pancreatic ß-cells.

The Influence of Stabilized Deconjugated Ursodeoxycholic Acid on Polymer-Hydrogel System of Transplantable NIT-1 Cells.

PURPOSE: The encapsulation of pancreatic ß-cells in biocompatible matrix has generated great interest in diabetes treatment. Our work has shown improved microcapsules when incorporating the bile acid ursodeoxycholic acid (UDCA), in terms of morphology and cell viability although cell survival remained low. Thus, the study aimed at incorporating the polyelectrolytes polyallylamine (PAA) and poly-l-ornithine (PLO), with the polymer sodium alginate (SA) and the hydrogel ultrasonic gel (USG) with UDCA and examined cell viability and functionality post microencapsulation. METHODS: Microcapsules without (control) and with UDCA (test) were produced using 1% PLO, 2.5% PAA, 1.8% SA and 4.5% USG. Pancreatic ß-cells were microencapsulated and the microcapsules' morphology, surface components, cellular and bile acid distribution, osmotic and mechanical stability as well as biocompatibilities, insulin production, bioenergetics and the inflammatory response were tested. RESULTS: Incorporation of UDCA at 4% into a PLO-PAA-SA formulation system increased cell survival (p < 0.01), insulin production (p < 0.01), reduced the inflammatory profile (TNF-α, IFN-ϒ, IL-6 and IL-1ß; p < 0.01) and improved the microcapsule physical and mechanical strength (p < 0.01). CONCLUSIONS: ß-cell microencapsulation using 1% PLO, 2.5% PAA, 1.8% SA, 4.5% USG and the bile acid UDCA (4%) has good potential in cell transplantation and diabetes treatment.

The impact of allylamine-bile acid combinations on cell delivery microcapsules in diabetes.

OBJECTIVE: In a recent study, we developed a new microencapsulating method for ß-cell microencapsulation, but cell viability declined rapidly, post microencapsulation, due to potential polymer-polyelectrolyte chelation and non-porous microcapsules' membranes resulting in cell apoptosis. Thus, this study tested the effects of incorporating cationic polyamine at 1% w/v, on microcapsule strength and cell viability, in the absence or presence of an anionic tertiary bile acid (ATBA) with potential cell-protective effects. METHODS: 1% w/v polyamine was used without or with ATBA, to form ß-cell microcapsules and physical and biological analyses was carried out 50 h post microencapsulation. RESULTS: Microcapsules containing 1% w/v polyamine showed weak physical properties and low cell viability and ATBA incorporation resulted in >30% reduction in cell viability and increased levels of pro-inflammatory cytokines. CONCLUSION: Neither 1% w/v polyamine nor the presence of ATBA resulted in optimised cell viability, but rather reduced cell viability, enhanced inflammation and lowered insulin secretion.

Novel chenodeoxycholic acid-sodium alginate matrix in the microencapsulation of the potential antidiabetic drug, probucol. An in vitro study.

CONTEXT: We previously designed, developed and characterized a novel microencapsulated formulation as a platform for the targeted delivery of Probucol (PB) in an animal model of Type 2 Diabetes. OBJECTIVE: The objective of this study is to optimize this platform by incorporating Chenodeoxycholic acid (CDCA), a bile acid with good permeation-enhancing properties, and examine its effect in vitro. Using sodium alginate (SA), we prepared PB-SA (control) and PB-CDCA-SA (test) microcapsules. RESULTS AND DISCUSSION: CDCA resulted in better structural and surface characteristics, uniform morphology, and stable chemical and thermal profiles, while size and rheological parameters remained unchanged. PB-CDCA-SA microcapsules showed good excipients' compatibilities, as evidenced by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy studies. CDCA reduced microcapsule swelling at pH 7.8 at both 37 °C and 25 °C and improved PB-release. CONCLUSION: CDCA improved the characteristics and release properties of PB-microcapsules and may have potential in the targeted oral delivery of PB.

Release and swelling studies of an innovative antidiabetic-bile acid microencapsulated formulation, as a novel targeted therapy for diabetes treatment.

In previous studies carried out in our laboratory, a bile acid formulation exerted a hypoglycaemic effect in a rat model of type 1 diabetes (T1D). When the antidiabetic drug gliclazide was added to the bile acid, it augmented the hypoglycaemic effect. In a recent study, we designed a new formulation of gliclazide-deoxycholic acid (G-DCA), with good structural properties, excipient compatibility and which exhibited pseudoplastic-thixotropic characteristics. The aim of this study is to test the slow release and pH controlled properties of this new formulation. The aim is also to examine the effect of DCA on G release kinetics at various pH values and different temperatures. Microencapsulation was carried out using our Buchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared including: G-SA (control) and G-DCA-SA (test) at a constant ratio (1:3:30), respectively. Microcapsules were examined for efficiency, size, release kinetics, stability and swelling studies at pH 1.5, 3, 7.4 and 7.8 and temperatures of 25 °C and 37 °C. The new formulation is further optimised by the addition of DCA. DCA reduced bead-swelling of the microcapsules at pH 7.8 and 3 at 25 °C and 37 °C, and even though bead size remains similar after DCA addition, the percentage of G release was enhanced at high pH values (pH 7.4 and 7.8, p < 0.01). The new formulation exhibits colon-targeted delivery and the addition of DCA prolonged G release suggesting its suitability for the sustained and targeted delivery of G and DCA to the lower intestine.

An advanced microencapsulated system: a platform for optimized oral delivery of antidiabetic drug-bile acid formulations.

INTRODUCTION: In previous studies, we have shown that a gliclazide-cholic acid derivative (G-CA) mixture resulted in an enhanced ileal permeation of G (ex vivo). When administered orally to diabetic rats, it brought about a significant hypoglycaemic effect. In this study, we aim to create a novel microencapsulated-formulation of G-CA with uniform and coherent structure that can be further tested in our rat model of type 1 diabetes (T1D). We also aim to examine the effect of CA addition to G microcapsules in the morphology, structure and excipients' compatibility of the newly designed microcapsules. METHOD: Microencapsulation was carried out using our Buchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared: G-SA (control) and G-CA-SA (test) at a constant ratio (1:3:30), respectively. Complete characterizations of microcapsules were carried out. RESULTS: The new G-CA-SA formulation is further optimized by the addition of CA exhibiting pseudoplastic-thixotropic rheological characteristics. Bead size remains similar after CA addition, the new microcapsules show no chemical interactions between the excipients and this was supported further by the spectral studies suggesting bead stability. CONCLUSION: The new microencapsulated-formulation has good and uniform structural properties and may be suitable for oral delivery of antidiabetic-bile acid formulations.

Probucol release from novel multicompartmental microcapsules for the oral targeted delivery in type 2 diabetes.

In previous studies, we developed and characterised multicompartmental microcapsules as a platform for the targeted oral delivery of lipophilic drugs in type 2 diabetes (T2D). We also designed a new microencapsulated formulation of probucol-sodium alginate (PB-SA), with good structural properties and excipient compatibility. The aim of this study was to examine the stability and pH-dependent targeted release of the microcapsules at various pH values and different temperatures. Microencapsulation was carried out using a Büchi-based microencapsulating system developed in our laboratory. Using SA polymer, two formulations were prepared: empty SA microcapsules (SA, control) and loaded SA microcapsules (PB-SA, test), at a constant ratio (1:30), respectively. Microcapsules were examined for drug content, zeta potential, size, morphology and swelling characteristics and PB release characteristics at pH 1.5, 3, 6 and 7.8. The production yield and microencapsulation efficiency were also determined. PB-SA microcapsules had 2.6 ± 0.25% PB content, and zeta potential of -66 ± 1.6%, suggesting good stability. They showed spherical and uniform morphology and significantly higher swelling at pH 7.8 at both 25 and 37°C (p < 0.05). The microcapsules showed multiphasic release properties at pH 7.8. The production yield and microencapsulation efficiency were high (85 ± 5 and 92 ± 2%, respectively). The PB-SA microcapsules exhibited distal gastrointestinal tract targeted delivery with a multiphasic release pattern and with good stability and uniformity. However, the release of PB from the microcapsules was not controlled, suggesting uneven distribution of the drug within the microcapsules.

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.

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.

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.

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.