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.

Pharmacological Effects of Secondary Bile Acid Microparticles in Diabetic Murine Model.

AIM: Examine bile acids effects in Type 2 diabetes. BACKGROUND: In recent studies, the bile acid ursodeoxycholic acid (UDCA) has shown potent antiinflammatory effects in obese patients while in type 2 diabetics (T2D) levels of the pro-inflammatory bile acid lithocholic acid were increased, and levels of the anti-inflammatory bile acid chenodeoxycholic acid were decreased, in plasma. OBJECTIVE: Hence, this study aimed to examine applications of novel UDCA microparticles in diabetes. METHODS: Diabetic balb/c adult mice were divided into three equal groups and gavaged daily with either empty microcapsules, free UDCA, or microencapsulated UDCA over two weeks. Their blood, tissues, urine, and faeces were collected for blood glucose, inflammation, and bile acid analyses. UDCA resulted in modulatory effects on bile acids profile without antidiabetic effects suggesting that bile acid modulation was not directly linked to diabetes treatment. RESULTS: UDCA resulted in modulatory effects on bile acids profile without antidiabetic effects suggesting that bile acid modulation was not directly linked to diabetes treatment. CONCLUSION: Bile acids modulated the bile profile without affecting blood glucose levels.

Bio Micro-Nano Technologies of Antioxidants Optimised Their Pharmacological and Cellular Effects, ex vivo, in Pancreatic ß-Cells.

INTRODUCTION: Recent formulation and microencapsulation studies of probucol (PB) using the polymer sodium alginate (SA) and bile acids have shown promising results but PB stability, and pharmacology profiles remain suboptimal. This study aimed to investigate novel polymers for the nano and micro encapsulation of PB, with the anti-inflammatory bile acid ursodeoxycholic acid (UDCA). MATERIAL AND METHODS: Six formulations using three types of polymers were investigated with and without UDCA. The polymers were NM30D, RL30D, and RS30D and they were mixed with SA and PB at set ratios and microencapsulated using oscillating-voltage-mediated nozzle technology coupled with ionic gelation. The microcapsules were examined for physical and biological effects using pancreatic ß-cells. RESULTS AND DISCUSSION: UDCA addition did not adversely affect the morphology and physical features of the microcapsules. Despite thermal stability remaining unchanged, bile acid incorporation did enhance the electrokinetic stability of the formulation system for NM30D and RL30D polymers. Mechanical stability remained similar in all groups. Enhanced uptake of PB from the microcapsule by pancreatic ß-cells was only seen with NM30D-UDCA-intercalated microcapsules and this effect was sustained at both glucose levels of 5.5 and 35.5 mM. CONCLUSION: UDCA addition enhanced PB delivery and biological effects in a formulation-dependent manner.

Modulatory Nano/Micro Effects of Diabetes Development on Pharmacology of Primary and Secondary Bile Acids Concentrations.

BACKGROUND: Recent studies have suggested that hyperglycaemia influences the bile acid profile and concentrations of secondary bile acids in the gut. INTRODUCTION: This study aimed to measure changes in the bile acid profile in the gut, tissues, and faeces in type 1 Diabetes (T1D) and Type 2 Diabetes (T2D). METHODS: T1D and T2D were established in a mouse model. Twenty-one seven-weeks old balb/c mice were randomly divided into three equal groups, healthy, T1D and T2D. Blood, tissue, urine and faeces samples were collected for bile acid measurements. RESULTS: Compared with healthy mice, T1D and T2D mice showed lower levels of the primary bile acid, chenodeoxycholic acid, in the plasma, intestine, and brain, and higher levels of the secondary bile acid, lithocholic acid, in the plasma and pancreas. Levels of the bile acid ursodeoxycholic acid were undetected in healthy mice but were found to be elevated in T1D and T2D mice. CONCLUSION: Bile acid profiles in other organs were variably influenced by T1D and T2D development, which suggests similarity in effects of T1D and T2D on the bile acid profile, but these effects were not always consistent among all organs, possibly since feedback mechanisms controlling enterohepatic recirculation and bile acid profiles and biotransformation are different in T1D and T2D.

Oral gavage of nano-encapsulated conjugated acrylic acid-bile acid formulation in type 1 diabetes altered pharmacological profile of bile acids, and improved glycaemia and suppressed inflammation.

BACKGROUND: Ursodeoxycholic acid (UDCA) is a secondary hydrophilic bile acid, metabolised in the gut, by microbiota. UDCA is currently prescribed for primary biliary cirrhosis, and of recently has shown ß-cell protective effects, which suggests potential antidiabetic effects. Thus, this study aimed to design targeted-delivery microcapsules for oral uptake of UDCA and test its effects in type 1 diabetes (T1D). METHODS: UDCA microcapsules were produced using alginate-NM30 matrix. Three equal groups of mice (6-7 mice per group) were gavaged daily UDCA powder, empty microcapsules and UDCA microcapsules for 7 days, then T1D was induced by alloxan injection and treatments continued until mice had to be euthanised due to weight loss > 10% or severe symptoms develop. Plasma, tissues, and faeces were collected and analysed for bile acids' concentrations. RESULTS: UDCA microcapsules brought about reduction in elevated blood glucose, reduced inflammation and altered concentrations of the primary bile acid chenodeoxycholic acid and the secondary bile acid lithocholic acid, without affecting survival rate of mice. CONCLUSION: The findings suggest that UDCA exerted direct protective effects on pancreatic ß-cells and this is likely to be associated with alterations of concentrations of primary and secondary bile acids in plasma and tissues. Three equal groups of mice were gavaged daily UDCA (ursodeoxycholic acid) powder, empty microcapsules and UDCA microcapsules for 7 days, then T1D was induced and treatments continued until mice had to be euthanised. UDCA microcapsules brought about reduction in elevated blood glucose, reduced inflammation and altered concentrations of the primary bile acid chenodeoxycholic acid and the secondary bile acid lithocholic acid, without affecting survival rate of mice. The findings suggest that UDCA exerted direct protective effects on pancreatic ß-cells and this is likely to be associated with alterations of concentrations of primary and secondary bile acids in plasma and tissues.

Stability and biological testing of taurine-conjugated bile acid antioxidant microcapsules for diabetes treatment.

AIM: Taurine-conjugated bile acids possess positive formulation-stabilization effects, which are desirable in diabetes treatments. The taurine-conjugated bile acid, taurocholic acid (TCA), has shown promising formulation-stabilizing effects on the delivery of the antioxidant drug, probucol (PB), but success is limited due to its poor release profile. This study aimed to design new PB-TCA formulations using new polymers, and examine antioxidant and antidiabetic effects using ß-cells for PB with or without TCA. MATERIALS AND METHODS: Different formulations using alginate-insoluble esters of polymethylacrylate polymers encapsulating PB and TCA were developed, microencapsulated and examined for stability and biological activity. RESULTS: TCA addition to new PB matrices improved osmotic and mechanical properties, and this effect was dependent on polymethylacrylate composition and concentration. CONCLUSION: TCA can optimize the oral delivery of anti-diabetic compounds.

An in vivo pharmacological study: Variation in tissue-accumulation for the drug probucol as the result of targeted microtechnology and matrix-acrylic acid optimization and stabilization techniques.

Type 2 diabetes (T2D) is characterised by ß-cell damage and hyperglycaemia. The lipophilic drug, probucol, has shown significant ß-cell protective and potential antidiabetic effects, which were enhanced by hydrophilic bile acid incorporation using taurocholic acid and chenodeoxycholic acid. However, probucol has severe cardiotoxicity and a variable absorption profile, which limit its potential applications in T2D. Accordingly, this study aimed to design multiple formulations to optimise probucol oral delivery in T2D and test their effects on probucol absorption and accumulation in the heart. Adult male mice were given a high fat diet (HFD), and a week later, injected with a single dose of alloxan to accelerate T2D development, and once diabetes confirmed, divided into three groups (six to seven mice each). The groups were gavaged a daily dose of probucol powder, probucol microcapsules, or probucol-bile acid microcapsules for three months, and euthanized; and blood, tissues, and feces collected for blood glucose and probucol concentration analyses. Probucol concentrations in plasma were similar among all the groups. Groups given probucol microcapsules and probucol-bile acid microcapsules showed significant reduction in probucol accumulation in the heart compared with the group given probucol powder (p<0.05). Probucol microencapsulation with or without bile acids reduced its accumulation in heart tissues, without changing plasma concentrations, which may be beneficial in reducing its cardiotoxicity and optimise its potential applications in T2D.

Probucol-poly(meth)acrylate-bile acid nanoparticles increase IL-10, and primary bile acids in prediabetic mice.

Aim: Common features in insulin-resistance diabetes include inflammation and liver damage due to bile acid accumulation. Results & methodology: This study aimed to test in vivo pharmacological effects of combining two drugs, ursodeoxycholic acid that has bile acid regulatory effects, and probucol (PB) that has potent anti-oxidative stress effects, using a new poly(meth)acrylate nano-targeting formulation on prediabetic mice. Mice were made diabetic and were fed daily with either PB, nanoencapsulated PB or nanoencapsulated PB-ursodeoxycholic acid before blood, tissues, urine and feces were collected for inflammation and bile acid measurements. The nanoencapsulated PB-ursodeoxycholic acid formulation increased plasma IL-10, and increased the concentration of primary bile acids in the liver and heart. Conclusion: Results suggest potential applications in regulating IL-10 in insulin-resistance prediabetes.

Novel nano-encapsulation of probucol in microgels: scanning electron micrograph characterizations, buoyancy profiling, and antioxidant assay analyses.

Smart polymers such as Eudragit (ED) have shown potential applications in oral drug delivery and targeted release. Probucol (PB) is a lipophilic drug used for hypercholesterolemia and possesses desirable antidiabetic effects such as antioxidant and cell protective effects. PB is highly hydrophobic and has poor bioavailability with significant inter- and intra-patient absorption, limiting its clinical applications in diabetes. This study aimed to design and analyse new PB-ED formulations with or without the absorption-enhancer chenodeoxycholic acid (CDCA). Sodium alginate-based microcapsules containing three different ED polymers (NM30D, RL30D and RS30D) were investigated with or without CDCA via scanning electron microscopy, energy dispersive X-ray spectroscopy (EDXR), confocal microscopy, osmotic stability, mechanical properties, buoyancy, release profiles (pH: 7.4), thermal stability and antioxidant effects. The effects of microcapsules on pancreatic ß-cell survival, function, inflammatory profile and PB cellular uptake were analysed. All microcapsules showed uniform morphology and surface topography with CDCA being distributed evenly throughout the microcapsules. Osmotic stability was significantly improved in PB-NM30D and PB-RL30D microcapsules (p < .01 and p < .05, respectively), and PB-NM30D microcapsules displayed low buoyancy (p < .01). CDCA improved PB-NM30D effects on pancreatic ß-cell function and bioenergetics, which suggests potential application of PB-NM30D-CDCA in PB delivery and diabetes treatment.

Eudragit®-based microcapsules of probucol with a gut-bacterial processed secondary bile acid.

AIM: Deoxycholic acid (DCA) has improved gliclazide oral absorption, while Eudragit® (ED) polymers have improved formulation stability of antidiabetic drugs. The aim of the study is to test if DCA and ED encapsulation will optimize the release and stability of the potential antidiabetic drug probucol (PB). MATERIALS & METHODS: The PB formulations were prepared using ED polymers and DCA, and formulations were analyzed for their rheological and biological properties. RESULTS: Rheological properties and size distribution were similar among all groups. ß-cell survival and biological activities were best with NM30D microcapsules. The inflammatory profile and oxidative stress effects of microcapsules remained similar among all groups. CONCLUSION: ED NM30D and DCA incorporation can exert positive and stabilizing effects on PB oral microcapsules.

Pharmacological effects of nanoencapsulation of human-based dosing of probucol on ratio of secondary to primary bile acids in gut, during induction and progression of type 1 diabetes.

INTRODUCTION: The ratio of secondary to primary bile acids changes during Type 1 Diabetes (T1D) development and these effects might be ameliorated by using cholesterol lowering drugs or hydrophilic bile acids. Probucol is a cholesterol-lowering drug, while ursodeoxycholic acid is a hydrophilic bile acid. This study investigated whether nanoencapsulated probucol with ursodeoxycholic acid altered bile acid ratios and the development of diabetes. METHODS: Balb/c mice were divided into three groups and gavaged daily with either free probucol, nanoencapsulated probucol or nanoencapsulated probucol with ursodeoxycholic acid for seven days. Alloxan was injected and once T1D was confirmed the mice continued to receive daily gavages until euthanasia. Blood, tissues, faeces and urine were collected for analysis of insulin and bile acids. RESULTS AND CONCLUSIONS: Nanoencapsulated probucol-ursodeoxycholic acid resulted in significant levels of insulin in the blood, lower levels of secondary bile acids in liver and lower levels of primary bile acids in brain, while ratio of secondary to primary bile acids remains similar among all groups, except in the faeces. Findings suggests that nanoencapsulated probucol-ursodeoxycholic acid may exert a protective effect on pancreatic ß-cells and reserve systemic insulin load via modulation of bile acid concentrations in the liver and brain.