Thiolated alginate-based multiple layer mucoadhesive films of metformin forintra-pocket local delivery: in vitro characterization and clinical assessment

Abstract

Introduction: Periodontal disease broadly defines group of conditions in which the supportive structure of the tooth (periodontium) is destroyed. Recent studies suggested that the anti-diabetic drug metformin hydrochloride (MF) has an osteogenic effect and is beneficial for the management of periodontitis.

Objective: Development of strong mucoadhesive multiple layer film loading small dose of MF for intra-pocket application.

Methodology: Multiple layer film was developed by double casting followed by compression method. Either 6% carboxy methyl cellulose sodium (CMC) or sodium alginate (ALG) constituted the inner drug (0.6%) loaded layer. Thiolated sodium alginate (TSA; 2 or 4%) constituted the outer drug free layers to enhance mucoadhesion and achieve controlled drug release. Optimized formulation was assessed clinically on 20 subjects.

Results: Films were uniform, thin and hard enough for easy insertion into periodontal pockets. Based on water uptake and in vitro drug release, CMC based film with 4% TSA as an outer layer was the optimized formulation with enhanced mucoadhesion and controlled drug release (83.73% over 12?h). SEM showed the effective fabrication of the triple layer film in which connective lines between the layers could be observed. FTIR examination suggests possibility of hydrogen bonding between the –NH groups of metformin and –OH groups of CMC. DSC revealed the presence of MF mainly in the amorphous form. Clinical results indicated improvement of all clinical parameters six months post treatment.

Conclusion: The results suggested that local application of the mucoadhesive multiple layer films loaded with metformin hydrochloride was able to manage moderate chronic periodontitis.     

Gamma-ray shielding properties of zinc oxide soda lime silica glasses

In the present work, the gamma ray shielding properties of zinc oxide soda lime silica, (ZnO)_x(SLS)_1?x glasses with 0 ≥ x ≥ 50 wt% have been investigated. By using WinXCom computer software, the mass attenuation coefficient (µ/ρ) and half value layer (HVL) for total photon interaction in the energy range of 1 keV–100 GeV were calculated. Furthermore and by Geometric Progression method exposure buildup factor values were calculated for incident photon energy 0.015–15 MeV up to penetration depths of 40 mfp (mean free path). The addition of zinc oxide (ZnO) into soda lime silica (SLS) glass resulted in an increase the mass attenuation coefficient and decreases both the half value layer and exposure buildup factor. The obtained results of the selected glass series have been compared, in terms of mass attenuation coefficient, half value layer and exposure buildup factor with some common shielding materials. The shielding effectiveness of the selected glasses is found comparable to that of common ones; which indicates that the SLS glasses with suitable ZnO content may be developed as gamma ray shielding materials.     

New results on the polymerisation of the itaconic acid in aqueous medium

Summary Itaconic acid has been polymerised in aqueous medium using potassium persulphate as initiator. An important dependence on the polymer yield with the initial pH of the reaction medium is observed. Polymers obtained on this work showed to be mainly atactic, with around 1.14 of polydispersity and molecular weight around 5 × 10⁵ ,g/mol. All the Polymers synthesized were characterized by FTIR, ¹H-NMR, ¹³C-NMR, gpc, thermogravimetry and acid number. Analysis of these materials seem to indicate a decrease of acidity related to the lost of one carboxylic group from the itaconic acid residue, probably due to intramolecular interactions when the monomer is incorporated into the polyiner growing chain. Received: 22 April 2002/Revised Version: 15 August 2002/ Accepted: 16 August 2002 RID="1*" ID="1*"Universidad del País Vasco, Facultad de Ciencias, Departamento de Química Bilbao, Espa?ia. Correspondence to Cristóbal Lárez V     

Corrosion inhibition of mild steel by schiff base compounds in various aqueous solutions: part 1

The corrosion inhibition by Schiff base compounds derived from diamines and o-hydroxy, o-methoxy aromatic aldehydes was investigated by weight loss, electrochemical measurements and surface analysis of SS 400 in various aqueous solutions such as tap water (LC), concentrated tap water (HC) and HCl solutions. The maximum inhibition efficiency (η) of N,N′-bis (salicylaldehyde)-1,12-diaminododecane (Saldn) for SS 400 in HCl solution approached 93%. The adsorption of Saldn on mild steel in HCl solution was obeyed Langmuirs isotherm.     

Effects of incorporation of interesterified plant oils on quality and fatty acid composition of Turkish‐type salami

Application of interesterified plant oils (IPOs) prepared from palm, cottonseed and olive oil (IPaO, ICO and IOO, respectively) have been studied in Turkish‐type salamis. Beef fat (10%) was replaced by one of the IPOs for 20, 60 or 100%. Incorporation of IPO was well reflected in fatty acid composition and saturated fatty acids/unsaturated fatty acids (SFA/UFA) ratios of the lipid fraction of all batches. Significant differences in appearance, color, texture, flavour or total score were not found among the control and Turkish‐type salamis with different types and levels of IPO. We conclude that IPOs may be successfully applied as beef fat substitutes in Turkish‐type salami.     

Physical properties of hydrogels of poly(2‐hydroxyethyl methacrylate) and copolymers with mono‐methyl itaconate synthesized by bulk and solution polymerization

The physical properties found during the swelling process of poly(2‐hydroxyethyl methacrylate) (PHEMA) and of copolymers of HEMA with mono‐n‐methyl itaconate, synthesized by solution and bulk polymerization, are reported. The swelling kinetics were followed at four different temperatures (295, 300, 305 and 310 K). Experimental data follow second‐order swelling kinetics, from where the kinetic rate constant k_∞ and the swelling capacity at equilibrium W_∞ were calculated as a function of temperature. The kinetic rate constant obeys Arrhenius behaviour. The following network parameters were determined for the hydrogels: Young's moduli E, effective crosslinking density v_e, molar mass per crosslink M_C, volume fraction ϕ₂ and polymer‐liquid interaction parameter χ. © 2000 Society of Chemical Industry     

Nachgiebiger Elektrodenträger für Cochlea-Implantate mit fluidischer Aktuierung

The cochlear implant, consisting of a compliant electrode carrier (ET) and embedded electrodes with contact wires, is an auditory neuroprosthesis, which is surgically inserted into the inner ear (cochlea) in order to create an auditory impression in the hearing-impaired patients. For simplification of the insertion, a fluidically actuated electrode carrier with a changeable curvature is presented. The deformation of the ET is specifically manipulated by applying pressure to its interior and also by a non-stretchable thin fibre or stripe embedded in its wall. An analytical examination of scaling properties allows to use scaled structures for models and measurements. In order to determine the geometry of the ET, a model-based synthesis – FE method combined with analytical modelling – is carried out. The synthesis resulted in a conical shape of the ET with a cylindrical cavity closed at one end and a fiber running parallel to the cavity. Experimental studies on a measuring geometry show a maximum deviation of 0,6 bar at a maximum internal pressure of 6 bar. The investigations show that the proposed synthesis method is suitable for the development of surgical instruments with adjustable curvature.     

Morphometric,quantitative, and three‐dimensional analysis of the heart muscle fibers of old rats: Transmission electron microscopy and high‐resolution scanning electron microscopy methods

This research investigated the morphological, morphometric, and ultrastructural cardiomyocyte characteristics of male Wistar rats at 18 months of age. The animals were euthanized using an overdose of anesthesia (ketamine and xylazine, 150/10 mg/kg) and perfused transcardially, after which samples were collected for light microscopy, transmission electron microscopy, and high‐resolution scanning electron microscopy. The results showed that cardiomyocyte arrangement was disposed parallel between the mitochondria and the A‐, I‐, and H‐bands and their M‐ and Z‐lines from the sarcomere. The sarcomere junction areas had intercalated disks, a specific structure of heart muscle. The ultrastructural analysis revealed several mitochondria of various sizes and shapes intermingled between the blood capillaries and their endothelial cells; some red cells inside vessels are noted. The muscle cell sarcolemma could be observed associated with the described structures. The cardiomyocytes of old rats presented an average sarcomere length of 2.071 ± 0.09 μm, a mitochondrial volume density (Vv) of 0.3383, a mitochondrial average area of 0.537 ± 0.278 μm², a mitochondrial average length of 1.024 ± 0.352 μm, an average mitochondrial cristae thickness of 0.038 ± 0.09 μm and a ratio of mitochondrial greater length/lesser length of 1.929 ± 0.965. Of the observed mitochondrial shapes, 23.4% were rounded, 45.3% were elongated, and 31.1% had irregular profiles. In this study, we analyzed the morphology and morphometry of cardiomyocytes in old rats, focusing on mitochondria. These data are important for researchers who focus the changes in cardiac tissue, especially changes owing to pathologies and drug administration that may or may not be correlated with aging. Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc.     

Fine Structure of Bacterial Adhesion to the Epithelial Cell Membranes of the Filiform Papillae of Tongue and Palatine Mucosa of Rodents: A Morphometric,TEM, and HRSEM Study

The palatine mucosa and filiform papillae of the dorsal tongue mucosae of rodents were examined using transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HRSEM). In the HRSEM method, the samples were fixed in 2% osmium tetroxide, dehydrated in alcohol, critical point‐dried, and coated with gold‐palladium. In addition, the HRSEM technique was used for morphometric analysis (length, width, and length/width ratio of cocci and bacilli). For the TEM method, the tissues were fixed in modified Karnovsky solution (2.5% glutaraldehyde, 2% formalin in 0.1M sodium phosphate buffer, pH 7.4) and embedded in Spurr resin. The results demonstrated that there are thick polygonal keratinized epithelial cells where groups of bacteria are revealed in three‐dimensional images on the surface of filiform papillae in these animals. The bacterial membranes are randomly attached to the microplicae surface of epithelial cells. Morphometrics showed higher values of length and width of cocci in newborn (0 day) as compared to newborn (7 days) and adults animals, the bacilli showed no differences in these measurements. At high magnification, the TEM images revealed the presence of glycocalyx microfilaments that constitute a fine adhesion area between bacterial membranes and the membranes of epithelial microplicae cells. In conclusion, the present data revealed the fine fibrillar structures of bacteria that facilitate adhesion to the epithelial cell membranes of the oral cavity and morphometric changes in newborn (0 day) rats as compared with other periods. Microsc. Res. Tech. 76:1226–1233, 2013. © 2013 Wiley Periodicals, Inc.     

Computer Simulation for Construction Education Using the Structure-Behavior-Function Theory: A Pilot Study on Learning Estimating Concepts

A computer simulation based on the structure-behavior-function (SBF) theory is developed and tested to study its impact on teaching construction estimating. While students eventually excel at estimating, grasping basic estimating concepts often presents a challenge to many students when they start learning estimating. It requires students to have a solid understanding about the relationship between actual construction and a typical estimating process to derive a good estimate. A computer simulation of a simple construction estimating process presents an opportunity for students to meet the challenge. One hundred and nine junior year students in a construction management department at a major state university in the southeastern United States participated in the study. The experimental group had sixty students using the simulation; while the control group had forty-nine students without using the simulation. The results showed that the simulation significantly improved students in learning both estimating concepts and processes (p = .05) and a significant portion (90%) of students felt that the simulation was helpful in learning estimating, but inconsistencies exist. The authors also identified and discussed limitations related to the findings.