Metformin ameliorates calcium oxalate crystallization and stone formation by activating the Nrf2/HO-1 signaling pathway: Two birds with one stone.

Deposition of calcium oxalate (CaOx) crystals and oxidative stress-induced injury of renal tubular epithelial cell are the primary pathogenic factors of nephrolithiasis. In this study we investigated the beneficial effects of metformin hydrochloride (MH) against nephrolithiasis and explored the underlying molecular mechanism. Our results demonstrated that MH inhibited the formation of CaOx crystals and promoted the transformation of thermodynamically stable CaOx monohydrate (COM) to more unstable CaOx dihydrate (COD). MH treatment effectively ameliorated oxalate-induced oxidative injury and mitochondrial damage in renal tubular cells and reduced CaOx crystal deposition in rat kidneys. MH also attenuated oxidative stress by lowering MDA level and enhancing SOD activity in HK-2 and NRK-52E cells and in a rat model of nephrolithiasis. In both HK-2 and NRK-52E cells, COM exposure significantlylowered the expressions of HO-1 and Nrf2, which was rescued by MH treatment even in the presence of Nrf2 and HO-1 inhibitors. In rats with nephrolithiasis, MH treatment significantly rescued the down-regulation of the mRNA and protein expression of Nrf2 and HO-1 in the kidneys. These results demonstrate that MH can alleviate CaOx crystal deposition and kidney tissue injury in rats with nephrolithiasis by suppressing oxidative stress and activating the Nrf2/HO-1 signaling pathway, suggesting the potential value of MH in the treatment of nephrolithiasis.

Phenolipid JE improves metabolic profile and inhibits gluconeogenesis via modulating AKT-mediated insulin signaling in STZ-induced diabetic mice.

Phenolipids are characteristic phytochemicals of Syzygium genus. However, the antidiabetic potential and underlying molecular mechanism of these components are not fully elucidated. Herein, we studied the anti-diabetic effects of jambone E (JE), a phenolipid from S. cumini, with in vitro and in vivo models. Data from current study showed that JE enhanced glucose consumption and uptake, promoted glycogen synthesis, and suppressed gluconeogenesis in insulin resistant (IR)-HepG2 cells and primary mouse hepatocytes. JE also attenuated streptozotocin-induced hyperglycemia and hyperlipidemia in type 1 diabetic (T1D) mice. Eleven metabolites (e.g. trimethylamine n-oxide, 4-pyridoxic acid, phosphatidylinositol 39:4, phenaceturic acid, and hippuric acid) were identified as potential serum biomarkers for JE's antidiabetic effects by an untargeted metabolomics approach. The further molecular mechanistic study revealed that JE up-regulated phosphorylation levels of protein kinase B (AKT), glycogen synthase kinase 3 beta, and forkhead box O1 (FoxO1), promoted nuclear exclusion of FoxO1 whilst decreased gene expression levels of peroxisome proliferator-activated receptor gamma coactivator-1 alpha, phosphoenolpyruvate carboxykinase and glucose 6-phosphatase in IR-HepG2 cells and T1D mice. Our data suggested that JE might be a potent activator for AKT-mediated insulin signaling pathway, which was confirmed by the usage of AKT inhibitor and AKT-target siRNA interference, as well as the cellular thermal shift assay. Findings from the current study shed light on the anti-diabetic effects of phenolipids in the Syzygium species, which supports the use of medicinal plants in the Syzygium genus for potential pharmaceutical applications.

Ground and Excited State Dipole Moments of Metformin Hydrochloride using Solvatochromic Effects and Density Functional Theory.

In this research, the ground (µg) and excited (µe) state dipole moments of metformin hydrochlorides were determined using Lippert-Mataga, Bakhshiev's, Kawski-Chamma-Viallet, and Reichardt models from fluorescence emission and UV-Vis absorption spectra in various solvents. From solvatochromic effects the calculated excited (µe ) dipole moment of metformin hydrochloride were, 8.55 D, 8.34 D, 6.08 D, and 6.40 D using the Lippert-Mataga, Bakhshiev's, Kawski-Chamma-Viallet and Reichardt models respectively. The results also indicated that the dipole moment at the ground state is smaller than the excited state. This is due to solvent polarity having a stronger effect on fluorescence emission than absorption spectra. Similarly, from density functional theory, the calculated ground and excited states dipole moments of metformin hydrochloride using (DFT-B3LYP- 3-21+G*(µg = 10.02 D and µe = 11.94 D), DFT-B3LYP- 6-31+G (d, p) (µg = 8.44 D and µe = 10.87 D), and DFT-B3LYP- 6-311+G (d, p) (µg = 8.24 D and µe = 18.74 D)) analyzed by Gaussian 09W. From the optimized geometry of the molecule, the HOMO-LUMO energy band gap of metformin hydrochloride were computed using DFT [DFT-B3LYP- 3-21+G*(5.51 eV), DFT-B3LYP- 6-31+G (d, p) (5.66 eV), and DFT-B3LYP- 6-311+G (d, p) (5.70 eV)] respectively.

Influence of permeability enhancers on the paracellular permeability of metformin hydrochloride and furosemide across Caco-2 cells.

Permeability enhancers can affect absorption of paracellularly transported drugs. This study aims to evaluate effects of permeability enhancers (chitosan, methyl-ß -cyclodextrin, sodium caprate, sodium lauryl sulfate, etc.) on the permeability of paracellularly absorbed furosemide and metformin hydrochloride. Methyl thiazole tetrazolium bromide test was carried out to determine the drug concentrations in permeability study. Trans-epithelial electrical resistance (TEER) values determined to assess the integrity of tight junctions. Permeability enhancers were applied at different concentrations alone, in dual/triple combinations. Permeability was determined using human colorectal adenocarcinoma (Caco-2) cells (TEER > 400 Ω·cm2). Permeability enhancers have no significant effect (<2-fold; p > 0.05) on the permeability of furosemide (1.80 × 10-5 ± 4.55 × 10-7 cm/s); however, metformin permeability (1.36 × 10-5 ± 1.25 × 10-6 cm/s) increased significantly (p < 0.05) with 0.3% and 0.5% (w/v) chitosan (2.0- and 2.7-fold, respectively), 1% methyl-ß -cyclodextrin (w/v) (3.5-fold), 10 and 20 µmol/L sodium caprate (2.2- and 2.8-fold, respectively), and 0.012% sodium lauryl sulfate (w/v) (1.9-fold). Furosemide permeability increased significantly (p < 0.05) with chitosan-sodium lauryl sulfate combination (1.7-fold), and all triple combinations (1.4- to 1.9-fold). Chitosan containing dual/triple combinations resulted in significant increase (p < 0.05) in metformin permeability (1.7 to 2.8-fold). All results indicated that absorption of furosemide and metformin can be improved by the combination of permeability enhancers. Therefore, it can be evaluated for the formulation of development strategies containing furosemide and metformin by the pharmaceutical industry.

Valuation of environmental influence of recently invented high-performance liquid chromatographic method for hypoglycemic mixtures of gliflozins and metformin in the presence of melamine impurities: Application of molecular modeling simulation approach.

Molecular modeling is the science of representing molecular structures numerically and simulating their behavior with the equations of quantum and classical physics. Coupling molecular modeling and simulation with chromatographic resolution for pharmaceutical products constitutes a new technique in pharmaceutical analysis. An innovative high-performance liquid chromatographic (HPLC) methodology was developed for the quantification of metformin hydrochloride (MET), empagliflozin (EMP), and canagliflozin (CAN) in bulk, laboratory-developed combinations, pharmaceutical tablets, and in the presence of melamine. Chromatographic separation was accomplished using a Symmetry column with 0.03 M potassium dihydrogen phosphate buffer and 0.02 M heptane sulphonic acid: acetonitrile as the mobile phase. Molecular modeling using molecular operating environment software was applied to properly select the stationary phase suitable for the developed HPLC method. Additionally, molecular modeling estimates and validates binding between the studied analytes and the stationary phase to clarify and explain the chromatographic separation and elution order. In accordance with the International Conference of Harmonization recommendations, the method was validated in terms of linearity, accuracy, precision, and selectivity. The linearity ranges (µg/ml) were 200-1500 (MET), 2-15 (EMP), and 20-150 (CAN) and the limit of detection values were in the ranges of 0.17-54.58 µg/ml. Analysis of pharmaceutical tablets using the suggested approach yielded satisfactory outcomes. As a result, it might be used in quality control laboratories to analyze the aforementioned medications.

Preparation and characterisation of self-emulsifying drug delivery system (SEDDS) for enhancing oral bioavailability of metformin hydrochloride using hydrophobic ion pairing complexation.

AIM: The aim of this study was preparation of a self-emulsifying drug delivery system (SEEDS) containing metformin hydrochloride. METHODS: Hydrophobic ion paired complexes were prepared by electrostatic interaction between metformin and sodium lauryl sulphate (SLS). The nanodroplets were optimised using two-level full factorial methodology and their morphology were examined. In vitro release of metformin from SEDDS was evaluated in simulated gastric and intestinal fluids. Finally, the ex-vivo efficacy of the optimised formulation in enhancing the intestinal permeability of metformin was evaluated using non-everted intestinal sac. RESULTS: The data revealed that in weight ratio 1:4(metformin: SLS), the highest recovery was achieved. The physico-chemical properties of the optimised nano-droplets including size, polydispersity index (PdI), zeta potential, and loading efficiency (%) were 192.33 ± 9.9 nm, 0.275 ± 0.051; -1.52 mV, and 93.75 ± 0.77% (w/w), respectively. CONCLUSIONS: The data obtained from the intestinal transport study demonstrated that SEDDS can significantly enhance the oral permeability of the compound.

In Vitro and In Vivo Evaluation of Metformin Hydrochloride Hydrogels Developed with Experimental Design in the Treatment of Burns.

Burns alter the normal skin barrier and affect various host defense processes that help prevent infections. An ineffective repair process can lead to serious damage, such as the onset of an infection or skin loss, which can then harm the surrounding tissues and ultimately the entire organism. This study aims to prepare in situ gels containing metformin hydrochloride, a compound known for its wound healing properties. To achieve this, in situ gels were prepared using three different gelling agents (Poloxamer 407®, Carbopol 934®, and sodium carboxymethyl cellulose (Na-CMC)) and three different concentrations of metformin hydrochloride (4 mg/g, 6 mg/g, and 8 mg/g), which were optimized through experimental design. Metformin concentration and gelling agent type were independent variables, and the loaded amount and the percentage of metformin released after 150 min were chosen as dependent variables in the optimization process. After determining the optimum values of the dependent variables according to the ANOVA analysis results, in vivo studies were conducted with optimized hydrogel formulations. Two groups, each consisting of seven Wistar rats with a burn model, were treated with metformin-poloxamer 407® gels at doses of 4 mg/g and 8 mg/g for 29 days. The results were then compared to untreated and placebo gel groups. Rats treated with in situ Poloxamer 407® hydrogels containing metformin hydrochloride showed a significant reduction in the size of the burned area after 29 days of treatment. However, for a comprehensive understanding of the wound healing mechanism, further studies such as immuno-histochemical and cell culture studies are needed.

PLGA-based microspheres loaded with metformin hydrochloride: Modified double emulsion method preparation, optimization, characterization, and in vitro evaluation.

The modified solvent removal method was used to encapsulate metformin hydrochloride (MH) within poly(lactic-co-glycolic acid) (PLGA) microspheres. The study investigated the effect of varying polymer concentrations on the loading and release of the drug from the microspheres. The encapsulation process involved using a double emulsion method, resulting in microspheres with particle diameters ranging from approximately 4.4µm to 2.7µm. The study achieved high encapsulation efficiencies, ranging from 81% to 90%, with drug loadings ranging from 18% to 11%. The release of the drug from the microspheres followed a biphasic pattern over 24 days, with nearly complete release by the end of the study period. Fourier transform infrared spectroscopy (FTIR) analysis indicated that there were no notable differences between PLGA and MH-loaded microspheres, suggesting minimal interactions between MH and PLGA. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques were used to investigate the state of the MH within the microspheres. The results suggested that the MH was dispersed at a molecular level within the spheres and existed in an amorphous state. This amorphous state of the drug may explain the slow and prolonged release observed in the study.

[Cross-Sectional Study on Adverse Effects of Metformin Hydrochloride on 130 Patients Type 2 Diabetic Admitted to Medical Center and Diabetes Home of Sidi Bel-Abbès]. / Étude Transversale sur les Effets Indésirables de la Chlorhydrate de Métformine chez 130 Patients Diabétiques Type 2 Admis au Centre Médical et à la Maison du Diabète de Sidi Bel-Abbès.

INTRODUCTION: MetforminHydrochloride is an antidiabetic used for many years, currently; it considered the first choice in treatment of type 2 diabetes (T2D). It decreases insulin resistance, does not induce hypoglycaemia, increases glucose utilization in the liver and skeletal muscle, and decreases hepatic glucose production. Its adverse effects (AE) are gastrointestinal, decrease in vitamin B12 absorption, abnormalities of hemogram and rarely skin reactions. The objective of this study was to report the type and frequency of AEs of Metformin Hydrochloride used in the therapeutic management of T2D patients admitted to the medical center and the diabetes home of Sidi Bel-Abbès in Algeria. MATERIALS AND METHODS: A cross-sectional descriptive study was carried out over a period of four months, from January 1st, 2017 to April 30th, 2017, involving 130 patients treated with Metformin Hydrochloride consulting at Mimoun City Diabetes Home and Gambetta Diabetes Center in the town of Sidi Bel-Abbès. The primary outcome measure was the determination of the type and frequency of AEs related to normal dosages or overdose use of Metformin Hydrochloride in T2D. Data were collected from patient records, using a questionnaire, and analyzed using Statistical Package for the Social Sciences, version 20 software. RESULTS: 130 patients were included, including 82 women, with a mean age of 51.08±8.85 years (30-66). One hundred and ninety-eight (198) AEs were reported, an average of 1.52 AEs per patient. Among them, 95 (47.98%) AEs are digestive disorders (30.77% of patients suffered from diarrhea, 10.77% had nausea and vomiting, 8.46% suffered from abdominal pain and bloating, 3.85% lost their taste, 7.69% complained of epigastric cramps and 11.54% of anorexia), 29 (14.65%) AEs are hypoglycaemia, 73 (36.87%) AEs are other symptoms and 1 (0.50%) EI is vitamin B12 deficiency and no cases of lactic acidosis or allergic reaction were reported. Five (3.85%) patients had a total and lasting intolerance to Metformin Hydrochloride leading to its discontinuation following persistent diarrhoea. CONCLUSION: AEs of Metformin Hydrochloride used in the management of T2D patients consulting at the medical center and the Diabetes home of Sidi Bel-Abbès are frequent. Digestive disorders were the most frequent, diarrhea was very frequent and led to discontinuation of treatment in 3.85% of T2D patients, followed by nausea and vomiting, then abdominal pain, bloating and epigastric cramps, and rarely taste metallic. Hypoglycaemia was frequent following its association with insulin, the onset of headaches and fatigue were frequent, but no case of lactic acidosis or allergic reaction was reported. Due to a lack of means, the dosage of homocysteine and methylmalonic acid had not been carried out to confirm the vitamin B12 deficiency in the patient whose level was less than 200ng/mL. A precise assessment of the imputability of reported AEs is necessary.

Metformin Hydrochloride Mucosal Nanoparticles-Based Enteric Capsule for Prolonged Intestinal Residence Time, Improved Bioavailability, and Hypoglycemic Effect.

Metformin hydrochloride enteric-coated capsule (MH-EC) is a commonly used clinical drug for the treatment of type 2 diabetes. In this study, we described a metformin hydrochloride mucosal nanoparticles enteric-coated capsule (MH-MNPs-EC) based on metformin hydrochloride chitosan mucosal nanoparticles (MH-CS MNPs) and its preparation method to improve the bioavailability and hypoglycemic effect duration of MH-EC. In intestinal adhesion study, the residue rates of free drugs and mucosal nanoparticles were 10.52% and 67.27%, respectively after cleaned with PBS buffer. MH-CS MNPs could significantly improve the efficacy of MH and promote the rehabilitation of diabetes rats. In vitro release test of MH-MNPs-EC showed continuous release over 12 h, while commercial MH-EC released completely within about 1 h in intestinal environment (pH 6.8). Pharmacokinetic study was performed in beagle dogs compared to the commercial MH-EC. The durations of blood MH concentration above 2 µg/mL were 9 h for MH-MNPs-EC versus 2 h for commercial MH-EC. The relative bioavailability of MH-MNPs-EC was determined as 185.28%, compared with commercial MH-EC. In conclusion, MH-CS MNPs have good intestinal adhesion and can significantly prolong the residence time of MH in the intestine. MH-MNPs-EC has better treatment effect compared with MH-EC, and it is expected to be a potential drug product for the treatment of diabetes because of its desired characteristics.

Different chromatographic methods for determination of alogliptin benzoate, metformin hydrochloride, and metformin impurity in bulk and pharmaceutical dosage form.

Two simple, sensitive, and reproducible methods were developed for the determination of alogliptin and metformin hydrochloride in presence of metformin impurity "melamin" in pure form and in pharmaceutical formulation. Method (A) was a thin layer chromatographic method in which separation was achieved using ethyl acetate-methanol-formic acid (6:3.8:0.2, by volume) as a developing system followed by densitometric scanning at 230 nm. Method (B) was a high-performance liquid chromatography method; separation was achieved on C18 column, the mobile phase consisted of a mixture of sodium lauryl sulfate buffer 0.1% w/v, pH 3: methanol in the ratio 70:30, v/v and measurement was done at 220 nm. System suitability testing parameters were calculated to ascertain the quality performance of the developed chromatographic methods. The proposed methods have been validated regarding accuracy, precision, and selectivity, moreover they have been successfully applied to Westirizide tablets containing both alogliptin and metformin hydrochloride, results indicate that there was no interference from additives. No significance difference was found when these methods were compared to the reported one.

Comparison of the performance of two grades of metformin hydrochloride elaboration by means of the SeDeM system, compressibility, compactability, and process capability indices.

Quality by design, applied to the development of a pharmaceutical drug, demands scientific methodologies, representing a source of information that will allow for a complete understanding the production process and the materials used for its manufacturing. Although the SeDeM system is a tool that enables a rational development of a product, result does not assure that an assessed material or mixture will be successful in terms of compression, hence, further research will be necessary on these features. The objective of this study was to assess and compare two grades of metformin hydrochloride elaboration: crystalline and direct compression using PXRD, the SeDeM expert system, the Heckel and Ryshkewitch-Duckworth models, as well as process control tools such as control charts and process capability indices to characterize and predict the performance of the materials in a direct compression process. The assessment identified that in spite of dealing with two different technical grades of a material with specific critical quality attributes for each one, PXRD analysis showed we dealt with the same crystalline structure, while the SeDeM system profiles obtained have very close values, and the main differences in materials were observed when subjecting them to conditions that simulate a compaction process with the Ryshkewitch-Duckworth model, in which a 46-times higher mechanical resistance was observed in the direct compression material compared with the crystalline one. The statistical control analysis revealed that only the direct compression material could be used to elaborate tablets whose weight variation was always maintained within the specification and control limits.

Adsorptive potential of Zea mays tassel activated carbon towards the removal of metformin hydrochloride from pharmaceutical effluent.

In the present study, Zea mays tassel which is a zero-value agricultural waste was used to produce a low-cost activated carbon using phosphoric acid as the activating agent. The prepared Z. mays tassel activated carbon (ZMTAC) was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The adsorbent was applied for adsorption of an emerging contaminant, metformin hydrochloride (MH) from pharmaceutical effluent. The effects of solution pH, contact time, adsorbent dosage, and initial MH concentration and their interactions were investigated using a response surface methodology following a central composite experimental design (CCD). The optimum experimental conditions were as follows: pH 9.5, contact time 67.50 min, dosage 0.5750 g, and MH concentration 152.50 mg/L. The isotherm data followed Langmuir isotherm model (R2 = 0.979; sum of square deviation, SSD = 0.321). The saturation adsorption capacity of ZMTAC was 44.84 mg/g at 20 °C. MH adsorption process followed pseudo-second-order kinetics (higher R2 and smaller SSD values). The thermodynamic properties obtained showed that the adsorption process was feasible, endothermic and spontaneous. Consequently, the study demonstrated that Z. mays tassel is a potential precursor for preparation of adsorbents for the removal of the MH from pharmaceutical effluent.

Preparation and characterization of metformin hydrochloride controlled-release tablet using fatty acid coated granules.

Metformin hydrochloride (MFM) is often used as a controlled-release (CR) tablet to reduce dosing frequency. However, the MFM CR tablet contains significant amounts of excipients and the tablet size is also large. Dosing convenience and patient compliance can be increased by reducing the size of the CR tablets. The aim of this study was to prepare and evaluate the MFM controlled-release tablet (MFM-CRT) using two types of release modulators, inner and outer. The MFM-CRT was prepared by coating the MFM granules using a binder solution containing aluminum stearate (ALS) as the inner release-modulator, and polyethylene oxide (PEO) as the outer release-modulator. The dispersion stability of the binder solution was optimized by the dispersion analyzer. The MFM-CRT was evaluated for dissolution rate and tablet volume. Additionally, dissolution behavior and dissolution kinetics of the MFM-CRT were analyzed using micro-computed tomography (micro-CT). Although the optimal MFM-CRT showed no difference in the release rate as compared to the commercially available product of Glucophage® XR 500 mg (f2 value: 72), the length of the long axis was reduced by 6 mm and the weight was reduced by about 27%. We expect patient compliance to improve because of effective sustained release and volume reduction of MFM-CRT.

Visualized analysis and evaluation of simultaneous controlled release of metformin hydrochloride and gliclazide from sandwiched osmotic pump capsule.

The aim of this study was to develop the Metformin Hydrochloride and Gliclazide (MH-GZ) sandwiched osmotic pump capsule which could overcome the problems associated with short half-life and burst release. The system could deliver drugs with different solubility simultaneously at zero-order rate, in which MH-GZ were filled in both sides of the push layer respectively. The single factor and orthogonal test were employed to obtain the optimized formulation with the evaluation index of similarity factor (ƒ2). R language was used to visualized analyze the main influence factors of drug release and their correlations. Pharmacokinetic study was performed in beagle dogs compared to the marketed conventional product, which showed decreased Cmax, prolonged Tmax, and improved bioavailability, independent of pH and agitational speed but related to osmotic pressure differences across the semi permeable membrane. The designed sandwiched osmotic pump capsule proposed a promising substitute for the marketed product for the treatment of type 2 diabetes.

Development and characterization of metformin hydrochloride- and glyburide-containing orally disintegrating tablets.

Diabetes is characterized by chronic hyperglycemia. Although metformin hydrochloride (MHCl)- and glyburide (GLB)-containing conventional tablets are available in the market and used to treat diabetes, orally disintegrating tablets (ODTs) containing the combination of these drugs are not commercially available. Therefore, the aim of this study was to prepare ODTs containing MHCl and GLB by direct-compression (DC-ODTs) and freeze-drying (FD-ODTs) methods. Physical properties of the powder mixture of DC-ODT formulation were determined (Angle of repose: 37.18 ± 1.27°; compressibility index: 20.31 ± 1.06%; Hausner ratio: 1.25 ± 0.03). Its moisture content was 0.3 ± 0.09%. The hardness values and the disintegration times for DC-ODTs and FD-ODTs were 221.60 ± 40.82 and 66.54 ± 2.68 N, and 80 and 30 s, respectively. Friability values were 0.24% for DC-ODTs and 0.38% for FD-ODTs. In uniformity-of-mass for single-dose-preparations test, the average weight was 684.38 ± 1.97 mg for DC-ODTs and 342.93 ± 2.4 mg for FD-ODTs, with less than 5% deviation for all 20 tablets. Water-absorption ratio for DC-ODTs was 1.30 ± 0.05. More than 90% of MHCl and GLB were dissolved within 5 min in both DC-ODTs and FD-ODTs. Although Caco-2 permeability of MHCl was influenced by the ODTs, GLB permeability was not. These results indicated that MHCl- and GLB-containing ODTs may be used as promising formulations for the treatment of diabetes.

Development of USP Apparatus 3 Dissolution Method with IVIVC for Extended Release Tablets of Metformin Hydrochloride and Development of a Generic Formulation.

Metformin is a euglycemic drug for the treatment of type 2 diabetes mellitus. To date, there are 13 dissolution methodologies described in the U.S. Pharmacopoeia (USP) to evaluate the release profile of metformin from extended-release tablets utilizing either a USP apparatus 1 (basket) or 2 (paddle). In the absence of a protocol for a USP apparatus 3 (reciprocating cylinder), the goal of this work was to develop an in vitro dissolution method for metformin extended-release tablets based on an in vivo-in vitro correlation (IVIVC). Following a systematic evaluation, a final dissolution method, M4, was defined. It applied 30 dips per minute (dpm) over a total period of 10 h into a series of solutions that included 2 h in HCl media (pH 1.2), 1 h in an acetate buffer solution (pH 4.5), 1 h in phosphate buffer solution (PBS) (pH 5.8) and 6 h in PBS (pH 6.8). This method showed a significant IVIVC with a calculated R2 > 0.98 (point-to-point correlation, Level A) and it was successfully used as a tool to assist in the development of generic extended release formulations for metformin consisting of a lipophilic matrix system.

BÜCHI nano spray dryer B-90: a promising technology for the production of metformin hydrochloride-loaded alginate-gelatin nanoparticles.

The current study aimed to formulate gelatin/sodium alginate nanoparticles utilizing BÜCHI nano spray dryer B-90. Nanoparticles possess many of the advantages including new routes of drug administrations and sustained release properties. Utilizing B-90 technology, metformin hydrochloride (MET) nanoparticles were successfully developed. Preformulation studies such as atomization head mesh size, flow rate, head temperature, polymer viscosity, and surface tension, were adjusted. Additionally, post-formulation characters such as particle size, flowability, surface scan, and dissolution profiles, were evaluated. Spray head (7 µm hole), flow rate (3.5 ml/min) and head temperature (120 °C) were optimized. Polymer viscosity was less than 11.2 cP with a surface tension less than 70.1 dyne/cm. Moreover, anti-diabetic effects of MET formulations were evaluated in streptozotocin-induced diabetic rats. Here, discrete, non-aggregated free-flowing nanoparticle powders with a particle size less than 850 nm were generated. Gelatin/sodium-alginate (1:3) produced nanoparticles were successfully sustained by the in vitro release profile of the drug. In vivo evaluations of the previous formula showed a significant reduction of blood glucose level over 24 h. In conclusion, Nano Spray Dryer B-90 (Büchi Labortechnik AG, Flawil, Switzerland) offers a promising technology for nanoparticles formulation as controlled drug delivery systems enhancing compliance of type-II diabetic patients.

Transdermal Cubic Phases of Metformin Hydrochloride: In Silico and in Vitro Studies of Delivery Mechanisms.

Transdermal delivery is one of important controlled drug release strategies for drug development. Cubic phases are the assemblies of amphiphilic molecules in water with the hydrophilic-hydrophobic interpenetrating network for transdermal delivery of both hydrophilic and hydrophobic drugs. However, many details about the transdermal delivery of drugs from cubic phases remain unclear. Here, metformin hydrochloride (Met) cubic phases were prepared with glyceryl monooleate (GMO), ethanol, and water. The cubic structure was identified with the polarizing light microscopy and small-angle X-ray scattering method. Dissipative particle dynamics (DPD) was used for building the microstructures of the cubic phases to explore the mechanism of drug release that mainly depended on drug diffusion from the water channels of cubic phases in accordance with the Higuchi equation of in vitro release experiments. The coarse-grained model and molecular docking method showed that GMO could enhance drug permeation through the skin by disturbing the interaction between Met and the skin proteins, and increasing the fluidity of skin lipids, which was confirmed with the Fourier transform infrared spectroscopy, Langmuir monolayer, and immunohistochemistry. Furthermore, in vitro permeation experiments showed the high Met transdermal improvement of cubic phases. Cubic phases are an ideal transdermal delivery system of Met. In silico methods are very useful for analyzing the molecular mechanisms of transdermal formulations.

Facile development, characterization, and optimization of new metformin-loaded nanocarrier system for efficient colon cancer adjunct therapy.

PURPOSE: Metformin hydrochloride (MF) repurposing as adjuvant anticancer therapy for colorectal cancer (CRC) proved effective. Several studies attempted to develop MF-loaded nanoparticles (NPs), however the entrapment efficiency (EE%) was poor. Thus, the present study aimed at the facile development of a new series of chitosan (CS)-based semi-interpenetrating network (semi-IPN) NPs incorporating Pluronic® nanomicelles as nanocarriers for enhanced entrapment and sustained release of MF for efficient treatment of CRC. METHODS: The NPs were prepared by ionic gelation and subsequently characterized using FTIR, DSC, TEM, and DLS. A full factorial design was also adopted to study the effect of various formulation variables on EE%, particle size, and zeta-potential of NPs. RESULTS: NPs had a spherical shape and a mean particle size ranging between 135 and 220 nm. FTIR and DSC studies results were indicative of successful ionic gelation with the drug being dispersed in its amorphous form within CS-Pluronic® matrix. Maximum EE% reaching 57.00 ± 12.90% was achieved using Pluronic®-123 based NPs. NPs exhibited a sustained release profile over 48 h. The MF-loaded NPs sensitized RKO CRC cells relative to drug alone. CONCLUSION: The reported results highlighted the novel utility of the developed NPs in the arena of colon cancer treatment.