Xylan from Pineapple Stem Waste: a Potential Biopolymer for Colonic Targeting of Anti-inflammatory Agent Mesalamine.

We have successfully conjugated mesalamine (5-aminosalicylic acid, 5-ASA) with xylan, a biopolymer isolated from pineapple stem waste, to form xylan-5-ASA conjugate. The biopolymer was used to provide colon-targeting properties for 5-ASA, a golden standard anti-inflammatory agent commonly used for ulcerative colitis treatment. A series of data from FTIR spectroscopy, UV-Vis spectrophotometry, and HPLC confirmed the xylan-5-ASA conjugate formation. To ensure successful colon targeting properties, in vitro and in vivo drug release studies after oral administration of xylan-5-ASA conjugate to Wistar rats were performed. Xylan-5-ASA conjugate was able to retain 5-ASA release in the upper gastrointestinal tract fluid simulation but rapidly released 5-ASA in the rat colon fluid simulation. In vivo release profile shows a very low peak plasma concentration, reached at 6 h after xylan-5-ASA conjugate administration. The delayed release and the lower bioavailability of 5-ASA from xylan-5-ASA conjugate administration compared to free 5-ASA administration confirmed the successful local colon delivery of 5-ASA using xylan-5-ASA conjugate. The administration of xylan-5-ASA conjugate also exhibited greater efficacy in recovering 2,4,6-trinitrobenzene sulfonic acid-induced colon ulcer compared to free 5-ASA administration. Taken together, xylan isolated from pineapple stem waste is promising to obtain colon targeting property for 5-ASA.

Intermolecular Interactions and the Release Pattern of Electrospun Curcumin-Polyvinyl(pyrrolidone) Fiber.

An electrospun fiber of polyvinyl(pyrrolidone) (PVP)-Tween 20 (T20) with curcumin as the encapsulated drug has been developed. A study of intermolecular interactions was performed using Raman spectroscopy, Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The Raman and FT-IR studies showed that curcumin preferrably interacted with T20 and altered PVP chain packing, as supported by XRD and physical stability data. The hydroxyl stretching band in PVP shifted to a lower wavenumber with higher intenstity in the presence of curcumin and PVP, indicating that hydrogen bond formation is more intense in a curcumin or curcumin-T20 containing fiber. The thermal pattern of the fiber did not indicate phase separation. The conversion of curcumin into an amorphous state was confirmed by XRD analysis. An in vitro release study in phosphate buffer pH 6.8 showed that intermolecular interactions between each material influenced the drug release rate. However, low porosity was found to limit the hydrogen bond-mediated release.

Curcumin nanoemulsion for transdermal application: formulation and evaluation.

The aim of this work is to develop a curcumin nanoemulsion for transdermal delivery. The incorporation of curcumin inside a nanoglobul should improve curcumin stability and permeability. A nanoemulsion was prepared by the self-nanoemulsification method, using an oil phase of glyceryl monooleate, Cremophor RH40 and polyethylene glycol 400. Evaluation of the nanoemulsion included analysis of particle size, polydispersity index, zeta potential, physical stability, Raman spectrum and morphology. In addition, the physical performance of the nanoemulsion in Viscolam AT 100P gel was studied. A modified vertical diffusion cell and shed snake skin of Python reticulatus were used to study the in vitro permeation of curcumin. A spontaneously formed stable nanoemulsion has a loading capacity of 350 mg curcumin/10 g of oil phase. The mean droplet diameter, polydispersity index and zeta potential of optimized nanoemulsion were 85.0 ± 1.5 nm, 0.18 ± 0.0 and -5.9 ± 0.3 mV, respectively. Curcumin in a nanoemulsion was more stable than unencapsulated curcumin. Furthermore, nanoemulsification significantly improved the permeation flux of curcumin from the hydrophilic matrix gel; the release kinetic of curcumin changed from zero order to a Higuchi release profile. Overall, the developed nanoemulsion system not only improved curcumin permeability but also protected the curcumin from chemical degradation.

Intraoral film containing insulin-phospholipid microemulsion: formulation and in vivo hypoglycemic activity study.

Non-invasive administration of insulin is expected for better diabetes mellitus therapy. In this report, we developed intraoral preparation for insulin. Insulin was encapsulated into nanocarrier using self-assembly emulsification process. To increase lipophilicity of insulin, it was dispersed in phospholipid resulted in insulin-phospholipid solid dispersion. The microemulsion formula was established from our previous work which contained glyceryl monooleate (GMO), Tween 20, and polyethylene glycol (PEG 400) in a ratio of 1:8:1. To confirm the formation of insulin-phospholipid solid dispersion, PXRD, FTIR spectroscopy, and Raman spectroscopy were performed. Then, the microemulsion was evaluated for droplet size and distribution, zeta potential, entrapment efficiency, physical stability, and Raman spectroscopy. In addition, microemulsion with expected characteristic was evaluated for in vitro release, in vitro permeation, and in vivo activity. The droplets size of ∼100 nm with narrow distribution and positive charge of +0.56 mV were formed. The insulin encapsulated in the oil droplet was accounted of >90%. Water-soluble chitosan seems to be a promising film matrix polymer which also functioned as insulin release controller. Oral administration of insulin microemulsion to healthy Swiss-Webster mice showed hypoglycemic effect indicating the success of this protein against a harsh environment of the gastrointestinal tract. This effectiveness significantly increased by fourfold as compared to free insulin. Taken together, microemulsion seems to be a promising carrier for oral delivery of insulin.

Effect of the Surfactant Charge on the Characteristics and Anticancer Effects of Docetaxel-loaded Poloxamer Polymeric Micelles.

BACKGROUND: The main problem in the use of docetaxel as a potent chemotherapeutic agent is its solubility. Practically insoluble docetaxel requires a harsh formulation with high surfactant and alcohol concentrations to comply with the product quality. However, this formulation is inconvenient for patients. Polymeric micelles using a biocompatible polymer, poloxamer, seem to be a promising approach to increase the solubility of docetaxel, avoiding the high polysorbate and alcohol contents in the commercial product and yielding similar or better anticancer effects. OBJECTIVE: This study aims to investigate the effects of surfactant with three different charges on the particle size, chemical stability, in vitro drug release and anticancer efficacy of the docetaxelloaded poloxamer-based polymeric micelle formulation. METHODS: The freeze drying method was used to prepare polymeric micelles of docetaxel. Dynamic light scattering was used to determine particle size. The morphology of particles was investigated using a transmission electron microscope. High Pressure Liquid Chromatography was used to measure encapsulation efficiency, drug loading, and percentage of drug released. MTT assay was used to assess the anticancer effect. RESULTS: Nonionic and anionic surfactants tended to increase the particle size, while cationic surfactants had no effect. Furthermore, the addition of cationic surfactant increased the chemical stability of docetaxel. Poloxamer polymeric micelles have sustained drug release, and the addition of a surfactant can increase polymeric micelle drug release. All surfactant charges increased the anticancer efficacy of docetaxel compared to the commercial formulation Taxotere, except for the formulation prepared with an anionic surfactant. CONCLUSION: The charge of the surfactant affects the particle size, chemical stability, drug release and anticancer properties of docetaxel-loaded poloxamer polymeric micelles. Cationic surfactant formulations have shown to be promising, resulting in the most stable and highest anticancer effect.

In-silico Molecular Interaction of Short Synthetic Lipopeptide/Importin-alpha and In-vitro Evaluation of Transgene Expression Mediated by Liposome- Based Gene Carrier.

BACKGROUND: Lipopeptide-based gene carriers have shown low cytotoxicity, are capable of cell membrane penetration, are easy to manufacture and therefore are great potential candidates for gene delivery applications. OBJECTIVES: This study aims to explore a range of short synthetic lipopeptides, (Lau: Lauryl; Pal: Palmitoyl) consisting of an alkyl chain, one cysteine (C), 1 to 2 histidine (H), and lysine (K) residues by performing in-silico molecular interaction and in-vitro evaluation. METHODS: The molecular interactions between the lipopeptides and Importin-α receptor were performed using AutoDock Vina and Amber14. The lipopeptide/DNA complexes were evaluated in- -vitro for their interactions, particle size, zeta potential and transgene expression. Transfection efficiency of the lipopeptides and Pal-CKKHH-derived liposome was carried out based on luciferase transgene expression. RESULTS: The in-silico interaction showed that Lau-CKKH and Pal-CKKHH hypothetically expedited nuclear uptake. Both lipopeptides had lower binding energy (-6.3 kcal/mol and -6.2 kcal/mol, respectively), compared to the native ligand, viz, nuclear localization sequence (-5.4 kcal/mol). The short lipopeptides were able to condense DNA molecules and efficiently form compacted nanoparticles. Based on the in-vitro evaluation on COS-7, Pal-CKKHH was found to be the best transfection agent amongst the lipopeptides. Its transfection efficiency (ng Luc/mg total protein) increased up to ~3-fold higher (1163 + 55) as it was formulated with helper lipid DOPE (1:2). The lipopeptide- based liposome (Pal-CKKHH: DOPE=1:2) also facilitated luciferase transgene expression on human embryonic kidney cells (293T) and human cervical adenocarcinoma cells (HeLa) with transfection efficiency 1779 +52 and 260 + 22, respectively. CONCLUSION: Our study for the first time has shown that the fully synthesized short lipopeptide Pal- CKKHH is able to interact firmly with the Importin-α. The lipopeptide is able to condense DNA molecules efficiently, facilitate transgene expression, expedite the nuclear uptake process, and hence has the characteristics of a potential transfection agent.

Physical-Chemical Crosslinked Electrospun Colocasia esculenta Tuber Protein-Chitosan-Poly(Ethylene Oxide) Nanofibers with Antibacterial Activity and Cytocompatibility.

BACKGROUND: Electrospun nanofibers based on Colocasia esculenta tuber (CET) protein are considered as a promising material for wound dressing applications. However, the use of these nanofibers in aqueous conditions has poor stability. The present study was performed to obtain insights into the crosslinked electrospun CET's protein-chitosan (CS)-poly(ethylene oxide) (PEO) nanofibers and to evaluate their potential for wound dressing applications. METHODS: The electrospun nanofibers were crosslinked with glutaraldehyde (GA) vapor and heat treatment (HT) to enhance their physicochemical stability. The crosslinked nanofibers were characterized by protein profiles, morphology structures, thermal behavior, mechanical properties, and degradation behavior. Furthermore, the antibacterial properties and cytocompatibility were analyzed by antibacterial assessment and cell proliferation. RESULTS: The protein profiles of the electrospun CET's protein-CS-PEO nanofibers before and after HT crosslinking contained one major bioactive protein with a molecular weight of 14.4 kDa. Scanning electron microscopy images of the crosslinked nanofibers indicated preservation of the structure after immersion in phosphate buffered saline. The crosslinked nanofibers resulted in higher ultimate tensile strength and lower ultimate strain compared to the non-crosslinked nanofibers. GA vapor crosslinking showed higher water stability compared to HT crosslinking. The in vitro antibacterial activity of the crosslinked nanofibers showed a stronger bacteriostatic effect on Staphylococcus aureus than on Escherichia coli. Human skin fibroblast cell proliferation on crosslinked GA vapor and HT nanofibers with 1% (w/v) CS and 2% (w/v) CET's protein demonstrated the highest among all the other crosslinked nanofibers after seven days of cell culture. Cell proliferation and cell morphology results revealed that introducing higher CET's protein concentration on crosslinked nanofibers could increase cell proliferation of the crosslinked nanofibers. CONCLUSION: These results are promising for the potential use of the crosslinked electrospun CET's protein-CS-PEO nanofibers as bioactive wound dressing materials.

Vitamin E-based Folic Acid Nanoemulsion: Formulation and Physical Evaluation for Oral Administration.

BACKGROUND: Folic acid is essential in many metabolic processes and DNA synthesis. Nevertheless, folic acid is not stable, pH-sensitive, and deteriorated upon light exposure. OBJECTIVE: This work was aimed to improve folic acid stability within vitamin E-based nanoemulsion. METHODS: The nanoemulsion was prepared with self-nanoemulsification method by mixing vitamin E oil, Tween 20, and PEG 400. A pseudoternary phase diagram was constructed with aqueous titration to determine the optimum ratio for the mixture. The globule size, pH and entrapment efficiency were included in the nanoemulsion characterizations. In addition, the influence of centrifugation, storage, and pH on physical and chemical stabilities of folic acid nanoemulsion was evaluated. RESULTS: Optimum formula was obtained from vitamin E, Tween 20, and PEG 400 with the ratio of 1:11:1, and the folic acid amount was 8 mg. The size of folic acidloaded oil globule was 15.10 ± 1.51 nm, and the nanoemulsion pH was 6.24 ± 0.01. The nanoemulsion system was able to load the folic acid completely. Folic acid in nanoemulsion was stable after 14 days at room temperature, and it was more stable compared to folic acid in solution. In addition, the physical and chemical characteristics of folic acid in nanoemulsion was not affected by the simulated gastric condition. CONCLUSION: Hence, nanoemulsion is a promising strategy to enhance folic acid stability.

Mangosteen pericarp extract embedded in electrospun PVP nanofiber mats: physicochemical properties and release mechanism of α-mangostin.

BACKGROUND: α-Mangostin is a major active compound of mangosteen (Garcinia mangostana L.) pericarp extract (MPE) that has potent antioxidant activity. Unfortunately, its poor aqueous solubility limits its therapeutic application. Purpose: This paper reports a promising approach to improve the clinical use of this substance through electrospinning technique. METHODS: Polyvinylpyrrolidone (PVP) was explored as a hydrophilic matrix to carry α-mangostin in MPE. Physicochemical properties of MPE:PVP nanofibers with various extract-to-polymer ratios were studied, including morphology, size, crystallinity, chemical interaction, and thermal behavior. Antioxidant activity and the release of α-mangostin, as the chemical marker of MPE, from the resulting fibers were investigated. RESULTS: It was obtained that the MPE:PVP nanofiber mats were flat, bead-free, and in a size range of 387-586 nm. Peak shifts in Fourier-transform infrared spectra of PVP in the presence of MPE suggested hydrogen bond formation between MPE and PVP. The differential scanning calorimetric study revealed a noticeable endothermic event at 119°C in MPE:PVP nanofibers, indicating vaporization of moisture residue. This confirmed hygroscopic property of PVP. The absence of crystalline peaks of MPE at 2θ of 5.99°, 11.62°, and 13.01° in the X-ray diffraction patterns of electrospun MPE:PVP nanofibers showed amorphization of MPE by PVP after being electrospun. The radical scavenging activity of MPE:PVP nanofibers exhibited lower IC50 value (55-67 µg/mL) in comparison with pure MPE (69 µg/mL). The PVP:MPE nanofibers tremendously increased the antioxidant activity of α-mangostin as well as its release rate. Applying high voltage in electrospinning process did not destroy the chemical structure of α-mangostin as indicated by retained in vitro antioxidant activity. The release rate of α-mangostin significantly increased from 35% to over 90% in 60 minutes. The release of α-mangostin from MPE:PVP nanofibers was dependent on α-mangostin concentration and particle size, as confirmed by the first-order kinetic model as well as the Hixson-Crowell kinetic model. CONCLUSION: We successfully synthesized MPE:PVP nanofiber mats with enhanced antioxidant activity and release rate, which can potentially improve the therapeutic effects offered by MPE.

In vivo and in vitro evaluation of a solid dispersion system of gliclazide:PEG 6000.

OBJECTIVE: Gliclazide is a potent antidiabetic agent because of its capability to decrease blood glucose level via stimulating endogenous insulin secretion from beta-pancreas cells. Gliclazide is insoluble in water and has low dissolution rate. In this study, polyethylene glycol (PEG) 6000 was used as a matrix to disperse gliclazide in the solid state, and the pharmacokinetic profile of this solid dispersion was studied in rats. DESIGN: The solid dispersion of Gliclazide:PEG 6000 (1:4) was prepared by solvent evaporation method. MAIN OUTCOME MEASURES: Samples characterization included differential scanning calorimetry (DSC), infrared spectroscopy (IR), X-ray diffraction (XRD), and solubility and dissolution test. In vivo study was carried out in healthy rats, randomly. After a single dose of oral administration, blood samples were collected pre-dose (15 min before) and 1, 2, 3, 4, 5, 6, 8, 10, and 12 h post-dose. Plasma concentration of gliclazide was determined by high pressure liquid chromatography method using C-18 column, with mobile phase KH2PO4 (pH 4.6)-acetonitril (40:60 v/v) and UV detection at 229 nm. RESULTS: Results showed that there were no differences in DSC, IR spectroscopy, XRD, and dissolution test between the solid dispersion and physical mixture. In vivo data showed that the Tmax of gliclazide in solid dispersion and physical mixture was significantly decreased, while the Cmax, AUC(0-12), and AUC(0-infinity) were significantly increased compared to gliclazide alone. These results indicate that the rapid Tmax was due to rapid absorption of gliclazid across the GI tract membrane. Increased Cmax, AUC(0-12), and AUC(0-infinity) indicate a better absorption of gliclazide in solid dispersion and physical mixture than of gliclazide alone. CONCLUSION: Increased in gliclazide dissolution in the presence of PEG 6000 was followed by improved in vivo data.

Development of curcumin nanocrystal: physical aspects.

Curcumin, a naturally occuring polyphenolic phytoconstituent, is isolated from the rhizomes of Curcuma longa Linn. (Zingiberaceae). It is water insoluble under acidic or neutral conditions but dissolves in alkaline environment. In neutral or alkaline conditions, curcumin is highly unstable undergoing rapid hydrolytic degradation to feruloyl methane and ferulic acid. Thus, the use of curcumin is limited by its poor aqueous solubility in acidic or neutral conditions and instability in alkaline pH. In the present study, curcumin nanocrystals were prepared using high-pressure homogenization, to improve its solubility. Five different stabilizers [polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), d-α-tocopherol polyethylene glycol 1000 succinate (TPGS), sodium dodecyl sulfate (SDS), carboxymethylcellulose sodium salt] possessing different stabilization mechanism were investigated. The nanoparticles were characterized with regard to size, surface charge, shape and morphology, thermal property, and crystallinity. A short-term stability study was performed storing the differently stabilized nanoparticles at 4°C and room temperature. PVA, PVP, TPGS, and SDS successfully produced curcumin nanoparticle with the particle size in the range of 500-700 nm. PVA, PVP, and TPGS showed similar performance in preserving the curcumin nanosuspension stability. However, PVP is the most efficient polymer to stabilize curcumin nanoparticle. This study illustrates that the developed curcumin nanoparticle held great potential as a possible approach to improve the curcumin solubility then enhancing bioavailability.