Intercalated theophylline-smectite hybrid for pH-mediated delivery

On the basis of their large specific surface areas, high adsorption and cation exchange capacities, swelling potential and low toxicity, natural smectite clays are attractive substrates for the gastric protection of neutral and cationic drugs. Theophylline is an amphoteric xanthine derivative that is widely used as a bronchodilator in the treatment of asthma and chronic obstructive pulmonary disease. This study considers the in vitro uptake and release characteristics of the binary theophylline-smectite system. The cationic form of theophylline was readily ion exchanged into smectite clay at pH 1.2 with a maximum uptake of 67±2 mg g−1. Characterisation of the drug-clay hybrid system by powder X-ray diffraction analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy confirmed that the theophylline had been exclusively intercalated into the clay system in an amorphous form. The drug remained bound within the clay under simulated gastric conditions at pH 1.2; and the prolonged release of approximately 40% of the drug was observed in simulated intestinal fluid at pH 6.8 and 7.4 within a 2-h timeframe. The incomplete reversibility of the intercalation process was attributed to chemisorption of the drug within the clay lattice. These findings indicate that smectite clay is a potentially suitable vehicle for the safe passage of theophylline into the duodenum. Protection from absorption in the stomach and subsequent prolonged release in the small intestine are advantageous in reducing fluctuations in serum concentration which may impact therapeutic effect and toxicit

Production of food nanomaterials by specialized equipment

In the past decade, there has been a great interest in using nanotechnology by different industries, including food, pharmaceutical, and beauty. Nanotechnology provides many advantages to produce functional compounds which tend to be delivered for desired properties, such as protection from the environment or food matrix, controlled release, and increased bioavailability and bioaccessibility (Muhammad et al., 2019, Sedaghat Doost et al., 2019b, Sedaghat Doost et al., 2018c). There is a variety of methods to prepare food nanomaterials. Specialized equipment is frequently employed for the production of efficient nano-delivery systems, which is the focus of this chapter; the basic principle of conventional and recent techniques, as well as their advantages and disadvantages are described

Nanoscaled dispersed systems used in drug-delivery applications

2-s2.0-85078197107Controlled drug-delivery nanotechnology is one of the most studied science fields bringing together chemists, biologists, physicists, pharmacists, and physicians to develop interdisciplinary knowledge. The main outcome followed is the same for all, particularly human health and patient compliance. The drug discovery technology is developing continuously so that many challenges arise day by day, delivery of poorly soluble drugs being one of them. Nanoscaled dispersions represent a smart strategy to formulate poorly soluble drugs and thus to improve poor absorption profile. The huge amount of scientific reports that have already been published concerning the nanoscaled dispersions for pharmaceutical and medical purposes has justified the great attention given to this topic. This chapter reviews the studies developed in the field of nanoscale dispersion systems, in particular micro-/nanoemulsions and polymeric nanodispersions used for drug-delivery systems with a focus on the last 5 years. © 2019 Elsevier Inc. All rights reserved

Eco-friendly chitosan-based nanocomposites: Chemistry and applications

The deacetylated chitin derivative, chitosan (CS), as a linear polysaccharide having reactive side amino groups is among the favorite bio-based materials due to its nontoxicity, biodegradability, biocompatibility, antimicrobial properties mucoadhesivity among other advantages. Chitosan as a hydrophilic biopolymer exhibits a variety of physicochemical and biological properties resulting in numerous applications in fields such as pharmaceutical and biopharmaceutical, cosmetics, biomedical engineering, biotechnology, agriculture, textiles, food processing nutrition, etc. The mechanical properties and hardness of CS are frequently not enough to meet some of the biomedical applications requirements. The addition even of a very small amount of nanoparticles leads to obtain materials with improved mechanical, chemical, and antimicrobial properties targeted to particular application. The mechanical, thermal, and antibacterial properties of the nanocomposites as well as their biodegradability and applications are reviewed. © Springer India 2015

Functionalized Chitosan for Pharmaceutical Applications

WOS: 000416527500005Background: Chitosan structure versatility toward a change in an external stimulus represents a "must have" for the pharmaceutical applications, especially for the pharmaceutical formulations. Chemical modification can open new ways to obtain materials with tailored properties. Despite the great interest for conventional graft modifications, controlled/ living free radical polymerizations (i.e. RAFT, ATRP, etc.) and advanced chemistry techniques (i.e. click chemistry) seem more attractive nowadays and involve facile and fast procedure, high regioselectivity, quantitative yield, mild reaction conditions without generation of by-products. Objective: The present review provides a detailed state of art of the chemical modification of chitosan i.e. tailored side-chain functionalization using RAFT polymerization and click chemistry for specific applications within pharmaceutical formulations taking into account the applicative aspect regarding the need of pharmaceuticals. Conclusion: The review showed the routes of current approaches for side chain modification of chitosan including graft, block copolymers or other structural variations. The esterification of RAFT agents on chitosan by using carbonyl activating reagents enables producing chitosan graft and block copolymers with controlled architectures while the development of protection/ deprotection chemistry of chitosan made possible the regioselective modification of chitosan or other polysaccharides. Although these developments increased the potential of chitosan, still the chemical functionality and architectural diversity of the derivatives are limited. Application of modern techniques e.g. RAFT polymerization, "click" chemistry has opened new "doors" for the science of controlled and chemoselective synthesis of well-tailored derivatives with unique and superior properties.The Scientific and Technological Research Council of Turkey (TUBITAK) - Marie Curie Actions under FP7 [115C078]Authors acknowledge the financial support from "The Scientific and Technological Research Council of Turkey (TUBITAK), cofunded by Marie Curie Actions under FP7", project number 115C078

Synthesis and Application of Reactive Acrylic Latexes: Effect of Particle Morphology

The aim of the study is the synthesis and characterization of epoxy functional reactive polyacrylic latexes, e.g., poly (BA-co-MMA-co-AN-co-GMA) with core/shell and non-structured (random) particle morphologies. Additionally, their performance as binders and coating ability in leather finishing were studied. The epoxy functional polymers were synthesized via the seeded emulsion polymerization technique and the obtained latexes were characterized by means of particle size, zeta potential, FTIR, TEM, DSC, DMTA, and TGA. The results showed that the particle size and zeta potential values were very similar for both latexes, except core/shell latex had slightly higher particle size. DSC, TEM, and DMTA studies verified the successful synthesis of core/shell latex morphology. The copolymer films were elastic in nature and had low T-g values (-13 and -20 degrees C). The performance results showed some different behavior for core/shell and random copolymer coatings. The abrasion resistance of the leather finish with random copolymer as binder exhibited slightly better values, especially in wet conditions. On the other hand, the leathers finished with core/shell binder showed better performance in flexing endurance and the water spotting test.SCIENTIFIC AND TECHNOLOGICAL RESEARCH COUNCIL OF TURKEY (TUBITAK) [115M650]This research was partly funded by THE SCIENTIFIC AND TECHNOLOGICAL RESEARCH COUNCIL OF TURKEY (TUBITAK), grant number 115M650