Influence of polymer blends on the characterization of gliclazide – encapsulated into poly (Æ-caprolactone) microparticles

The Effects of Accelerated Temperature-Controlled Stability Systems on the Release Profile of Primary Bile Acid-Based Delivery Microcapsules

Introduction: Bile acid-based drug encapsulation for oral delivery has been recently explored in our laboratory and has shown to be beneficial in terms of drug-targeted delivery and release profile, but stability at various temperatures has not previously been examined; hence, this is the aim of this study. Methods: Various types of bile acid-based microcapsules containing the drug metformin were produced and tested for accelerated temperature-controlled profiles, as well as morphology, elemental composition, drug content, resilience, floatability, wettability and release profiles at various pH values. Results: Accelerated temperature-controlled analysis showed negligible effects on morphology, size, or shape at very low temperatures (below 0 °C), while higher temperatures (above 25 °C) caused alterations. Drug contents, morphology and elemental composition remained similar, while wettability and the release profiles showed formulation-dependent effects. Discussion and Conclusion: Results suggest that bile acid-based microcapsules containing metformin are affected by temperature; hence, their shelf life is likely to be affected by storage temperature, all of which have a direct impact on drug release and stability profiles.

Pharmacological and Biological Study of Microencapsulated Probucol-Secondary Bile Acid in a Diseased Mouse Model

Probucol (PB) is a highly lipophilic drug with potential protective effects on pancreatic β-cells from inflammation and oxidation. PB has poor bioavailability and solubility, and despite many attempts, significant improvement in antidiabetic effects or absorption has yet to be discovered. Recently, the role of bile acids has been established in significant drug formulation stabilisation effects and as cell-penetrating agents. Promising results in pharmaceutical formulation studies on drug stability and release patterns when lithocholic acid (LCA) is conjugated with PB and sodium alginate (SA) have been demonstrated. Thus, this study aimed to develop and characterise PB microcapsules incorporating LCA and examine the biological effects of the microcapsules in vitro and in vivo. PB/LCA microcapsules were prepared using an encapsulation method, ionic gelation vibrational jet flow technology. LCA incorporation in PB microcapsules showed positive effects on β-cells with improved insulin release, antioxidant activity, and PB intracellular uptake. Diabetic mice gavaged LCA-PB microcapsules showed a significant reduction in diabetes signs and symptoms, better survival rate, reduced blood glucose levels, and pro-inflammatory cytokines, with an increase PB level in blood and tissues suggesting a potential therapy for treating diabetes mellitus.

Pharmacological and Advanced Cell Respiration Effects, Enhanced by Toxic Human-Bile Nano-Pharmaceuticals of Probucol Cell-Targeting Formulations

Bile acids have recently been studied for potential applications as formulation excipients and enhancers for drug release; however, some bile acids are not suitable for this application. Unconjugated lithocholic acid (ULCA) has recently shown drug formulation-stabilizing and anti-inflammatory effects. Lipophilic drugs have poor gut absorption after an oral dose, which necessitates the administration of high doses and causes subsequent side effects. Probucol (PB) is a highly lipophilic drug with poor oral absorption that resulted in restrictions on its clinical prescribing. Hence, this study aimed to design new delivery systems for PB using ULCA-based matrices and to test drug formulation, release, temperature, and biological effects. ULCA-based matrices were formulated for PB oral delivery by applying the jet-flow microencapsulation technique using sodium alginate as a polymer. ULCA addition to new PB matrices improved the microcapsule’s stability, drug release in vitro (formulation study), and showed a promising effect in ex vivo study (p < 0.05), suggesting that ULCA can optimize the oral delivery of PB and support its potential application in diabetes treatment.

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 β-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 β-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.

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. β-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.

Morphological, Stability, and Hypoglycemic Effects of New Gliclazide-Bile Acid Microcapsules for Type 1 Diabetes Treatment: the Microencapsulation of Anti-diabetics Using a Microcapsule-Stabilizing Bile Acid

When we administered orally a mixture of the anti-diabetic drug, gliclazide (G) and a primary bile acid, they exerted a hypoglycemic effect in a rat model of type 1 diabetes (T1D), but stability of mixture was limited. We aimed to develop and characterize microcapsules incorporating G with a microcapsule-stabilizing bile acid, ursodeoxycholic acid (UDCA). Sodium alginate (SA)-based microcapsules were prepared with either G or G with UDCA and analyzed in terms of morphological, physico-chemical, and electro-chemical characteristics at different pH and temperatures. The microcapsules' effects on viability on muscle cell line (C2C12) and on diabetic rats' blood glucose levels and inflammatory profiles were also examined. Bile acid-based microcapsules maintained their morphology, showed good stability, and compatibility profiles, and the incorporation of UDCA resulted in less G content per microcapsule (p < 0.01) and production of stronger microcapsules that were more resistant to mechanical pressure (p < 0.01). G-UDCA-SA microcapsules enhanced muscle cell viability at higher glucose concentrations compared with control (G-SA and UDCA-SA), and they had strong anti-inflammatory effects on diabetic rats. In addition, the incorporation of UDCA into G microcapsules enhanced the physical characteristics of the microcapsules and optimized G delivery after oral administration.

A comprehensive study of novel microcapsules incorporating gliclazide and a permeation enhancing bile acid: hypoglycemic effect in an animal model of Type-1 diabetes

CONTEXT

Gliclazide (G) is a commonly prescribed drug for Type 2 diabetes (T2D). In a recent study, we found that when G was combined with a primary bile acid, and gavaged to an animal model of Type 1 diabetes (T1D), it exerted a hypoglycemic effect. We hypothesized this to be due to metabolic activation of the primary bile acid into a secondary or a tertiary bile acid, which enhanced G solubility and absorption. The tertiary bile acid, taurocholic acid (TCA), has shown strong permeation-enhancing effects in vivo. Thus, we aimed to design, characterize, and test microcapsules incorporating G and TCA in an animal model of T1D.

METHODS

Microcapsules were prepared using the polymer sodium alginate (SA). G-SA microcapsules (control) and G-TCA-SA microcapsules (test) were extensively examined (in-vitro) at different pH and temperatures. The microcapsules were gavaged to diabetic rats, and blood glucose and G concentrations in serum were examined. Ex-vivo studies were also performed using a muscle cell line (C2C12), and cell viability and glucose intake post-treatment were examined.

RESULTS

G-TCA-SA microcapsules showed good stability, uniformity, and thermal and chemical excipient compatibilities. TCA did not change the size or the shape of the microcapsules, but it enhanced their mechanical resistance and reduced their swelling properties. G-TCA-SA enhanced the viability of C2C12 cells over 24 hours, and exerted a hypoglycemic effect in alloxan-induced type-1 diabetic rats.

CONCLUSIONS

The incorporation of TCA into G-microcapsules resulted in functionally improved microcapsules with a positive effect on cell viability and glycemic control in Type-1 diabetic animals.

The role of the bile acid chenodeoxycholic acid in the targeted oral delivery of the anti-diabetic drug gliclazide, and its applications in type 1 diabetes

Gliclazide (G) is used to treat type 2 diabetes (T2D), and also has anti-platelet, anti-radical, and anti-inflammatory effects. G has poor water solubility and high inter-individual variations in absorption, limiting its application in type 1 diabetes (T1D). The bile acid, chenodeoxycholic acid (CDCA), has permeation-enhancing effects. Sodium alginate (SA) was used to microencapsulate G and CDCA to produce control (G-SA) and test (G-CDCA-SA) microcapsules. Both microcapsules showed uniform structure, morphology, and good stability profiles. CDCA reduced G-release at pH 7.8, while G-release was negligible at lower pH values in both microcapsules. CDCA incorporation resulted in less swelling and stronger microcapsules, suggesting improved stability.

Novel drug delivery system: an immense hope for diabetics

CONTEXT

Existing medication systems for the treatment of diabetes mellitus (DM) are inconvenient and troublesome for effective and safe delivery of drugs to the specific site. Therefore, investigations are desired to deliver antidiabetics using novel delivery approaches followed by their commercialization.

OBJECTIVE

The present review aims to provide a compilation on the latest development in the field of novel drug delivery systems (NDDSs) for antidiabetics with special emphasis on particulate, vesicular and miscellaneous systems.

METHODS

Review of literature (restricted to English language only) was done using electronic databases like Pubmed® and Scirus, i.e. published during 2005-2013. The CIMS/MIMS India Medical Drug Information eBook was used regarding available marketed formulation of antidiabetic drugs. Keywords used were "nanoparticle", "microparticle", "liposomes", "niosomes", "transdermal systems", "insulin", "antidiabetic drugs" and "novel drug delivery systems". Single inclusion was made for one article. If in vivo study was not done then article was seldom included in the manuscript.

RESULTS

The curiosity to develop NDDSs of antidiabetic drugs with special attention to the nanoparticulate system followed by microparticulate and lipid-based system is found to emerge gradually to overcome the problems associated with the conventional dosage forms and to win the confidence of end users towards the higher acceptability.

CONCLUSION

In the current scientific panorama when the area of novel drug delivery system has been recognized for its palpable benefits, unique potential of providing physical stability, sustained and site-specific drug delivery for a scheduled period of time can open new vistas for precise, safe and quality treatment of DM.

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.

Novel artificial cell microencapsulation of a complex gliclazide-deoxycholic bile acid formulation: a characterization study

Gliclazide (G) is an antidiabetic drug commonly used in type 2 diabetes. It has extrapancreatic hypoglycemic effects, which makes it a good candidate in type 1 diabetes (T1D). In previous studies, we have shown that a gliclazide-bile acid mixture exerted a hypoglycemic effect in a rat model of T1D. We have also shown that a gliclazide-deoxycholic acid (G-DCA) mixture resulted in better G permeation in vivo, but did not produce a hypoglycemic effect. In this study, we aimed to develop a novel microencapsulated formulation of G-DCA with uniform structure, which has the potential to enhance G pharmacokinetic and pharmacodynamic effects in our rat model of T1D. We also aimed to examine the effect that DCA will have when formulated with our new G microcapsules, in terms of morphology, structure, and excipients' compatibility. Microencapsulation was carried out using the Büchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared: G-SA (control) at a ratio of 1:30, and G-DCA-SA (test) at a ratio of 1:3:30. Complete characterization of microcapsules was carried out. The new G-DCA-SA formulation was further optimized by the addition of DCA, exhibiting pseudoplastic-thixotropic rheological characteristics. The size of microcapsules remained similar after DCA addition, and these microcapsules showed no chemical interactions between the excipients. This was supported further by the spectral and microscopy studies, suggesting microcapsule stability. The new microencapsulated formulation has good structural properties and may be useful for the oral delivery of G in T1D.

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.

Stability and Release Kinetics of an Advanced Gliclazide-Cholic Acid Formulation: The Use of Artificial-Cell Microencapsulation in Slow Release Targeted Oral Delivery of Antidiabetics

Introduction

In previous studies carried out in our laboratory, a bile acid (BA) formulation exerted a hypoglycaemic effect in a rat model of type-1 diabetes (T1D). When the antidiabetic drug gliclazide (G) was added to the bile acid, it augmented the hypoglycaemic effect. In a recent study, we designed a new formulation of gliclazide-cholic acid (G-CA), with good structural properties, excipient compatibility and exhibits 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 CA on G release kinetics at various pH values and different temperatures.

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. Microcapsules were examined for efficiency, size, release kinetics, stability and swelling studies at pH 1.5, pH 3, pH 7.4 and pH 7.8 and temperatures of 20 and 30 °C.

Results

The new formulation is further optimised by the addition of CA. CA reduced microcapsule swelling of the microcapsules at pH 7.8 and pH 3 at 30 °C and pH 3 at 20 °C, and, even though microcapsule size remains similar after CA addition, percent G release was enhanced at high pH values (pH 7.4 and pH 7.8, p < 0.01).

Conclusion

The new formulation exhibits colon-targeted delivery and the addition of CA prolonged G release suggesting its suitability for the sustained and targeted delivery of G and CA to the lower intestine.

Feasibility of poly (ϵ-caprolactone-co-DL-lactide) as a biodegradable material for in situ forming implants: evaluation of drug release and in vivo degradation

The purpose of this study was to evaluate the technical feasibility of poly (ϵ-caprolactone-co-DL-lactide), P (CL/DL-LA), for injectable in situ forming implants (ISFI). The ISFI was prepared by dissolving P (CL/DL-LA) in N-methyl-2-pyrrolidone (NMP), and Testosterone undecanoate (TU) was used as model drug. The effect of various polymer concentrations, molecular weights (Mws) and drug loads on the drug release from the TU-loaded ISFI systems was investigated in vitro. The release of TU-loaded ISFI was also evaluated in rats. In addition, a subcutaneous rabbit model was used to evaluate the degradation and foreign-body reaction of P (CL/DL-LA) ISFI. The use of higher concentration of P (CL/DL-LA) with higher molecule weight and larger CL:DL-LA monomer ratio for the TU-loaded ISFI gave a slower drug release. The ISFI of 80/20 P (CL/DL-LA) (Mw 61 753):NMP 20:80 with 16% TU formulation increased serum testosterone levels in rats over a period of three months. The in vivo degradation and biocompatibility study of ISFI shows that P (CL/DL-LA) degrades by a process of bulk degradation and that the foreign-body reaction of this biomaterial is relatively mild. In summary, our investigations demonstrate that in situ parenteral drug delivery systems can be obtained from P (CL/DL-LA) solutions.