Methods for the Chemical Analysis of Degradable Synthetic Polymeric Biomaterials

Controlled drug release contenders comprising starch/poly(allylamine hydrochloride) biodegradable composite films

The blending of natural polysaccharides with synthetic polymers has attracted much attention in drug delivery models owing to their remarkable biodegradable and biocompatible characteristics. This study focuses on the facile preparation of a sequence of composite films having Starch/Poly(allylamine hydrochloride) (ST/PAH) in different compositions to propose a novel drug delivery system (DDS). ST/PAH blend films were developed and characterized. FT-IR evaluation confirmed the involvement of intermolecular H-bonding between the ST and PAH counterparts in blended films. The water contact angle (WCA) ranged from 71° to 100° indicating that all the films were hydrophobic. TPH-1 (90 % ST and 10 % PAH) was evaluated for in vitro controlled drug release (CDR) at 37 ± 0.5 °C in a time-dependent fashion. CDR was recorded in phosphate buffer saline (PBS) and simulated gastric fluid (SGF). In the case of SGF (pH 1.2), the percentile drug release (DR) for TPH-1 was approximately 91 % in 110 min, while the maximum DR was 95 % in 80 min in PBS (pH 7.4) solution. Our results demonstrate that the fabricated biocompatible blend films can be a promising candidate for a sustained-release DDS for oral drug administration, tissue engineering, wound dressings, and other biomedical applications.

Mass spectrometry in bioresorbable polymer development, degradation and drug-release tracking

A detailed characterization of polymeric matrices and appropriate degradation monitoring techniques are required to sustain the development of new materials as well as to enlarge the applications of the old ones. In fact, polymer analysis is essential for the clarification of the intrinsic relationship between structure and properties that ascertains the industrial applications in diverse fields. In bioresorbable and biodegradable polymers, the role of analytical methods is dual since it is pointed both at the polymeric matrices and at degradation tracking. The structural architectures, the mechanical and morphological properties, and the degradation rate, are of outstanding importance for a specific application. In some cases, the complexity of the polymer structure, the processes of decomposition or the low concentration of the degradation products need the concurrent use of different complementary analytical techniques to give detailed information of the reactions taking place. Several analytical methods are used in bioresorbable polymer development and degradation tracking. Among them, mass spectrometry (MS) plays an essential role and it is used to refine polymer syntheses, for its high sensitivity, to highlight degradation mechanism by detecting compounds present in trace amounts, or to track the degradation product profile and to study drug release. In fact, elucidation of reaction mechanisms and polymer structure, attesting to the purity and detecting defects as well as residual catalysts, in biodegradable and bioresorbable polymers, requires sensitive analytical characterization methods that are essential in providing an assurance of safety, efficacy and quality. This review aims to provide an overview of the MS strategies used to support research and development of resorbable polymers as well as to investigate their degradation mechanisms. It is focused on the most significant studies concerning synthetic bioresorbable matrices (polylactide, polyglycolide and their copolymers, polyhydroxybutyrate, etc.), published in the last ten years.

Emissions of selected monoaromatic hydrocarbons as a factor affecting the removal of single-use polymer barbecue and kitchen utensils from everyday use

The main focus of this study is the emission of monoaromatic hydrocarbons because these are the preliminary factors of potential solvent and monomer residues present in single-use plastic barbecue and kitchen utensils comprising polystyrene, polypropylene, natural cellulose, and biodegradable polymers intended for use with hot meal or beverages. Herein, the emissions of monoaromatic hydrocarbons (styrene, benzene, toluene, ethylbenzene, and xylene compounds and the total volatile organic compounds (TVOC)) from nine types of disposable plastic utensils are reported. Seventy two samples of single-use plastic utensils were conditioned at 40 and 80 °C using a stationary emission microchamber system. The average TVOC released from the studied polystyrene, polypropylene, and natural or biodegradable utensils were (2.3 ± 1.3), (1.01 ± 0.15), and (0.48 ± 0.37) μg g^-1, respectively, at 40 °C and (11.1 ± 1.2), (46.1 ± 9.5), and (5.5 ± 1.1) μg g^-1, respectively, at 80 °C. Significant emissions of styrene (ranged from 3.5 up to 15.3 × 10³ ng∙g^-1), toluene (from 2.8 up to 0.53 × 10³ ng∙g^-1), and ethylbenzene (from 3.7 up to 5.7 × 10³ ng∙g^-1) from the studied samples were observed, especially at 80 °C. Thus, elevated temperatures increase the potential emission of solvent and monomer residues from plastics and could affect the quality of consumed meals or beverages, such as taste. Additionally, to determine the possible interactions between the measured chemical compounds in the plastic utensils, the Pearson's correlation coefficients were calculated.

A Smart Drug Delivery System Based on Biodegradable Chitosan/Poly(allylamine hydrochloride) Blend Films

The amalgamation of natural polysaccharides with synthetic polymers often produces fruitful results in the area of drug delivery due to their biodegradable and biocompatible nature. In this study, a series of blend films composed of chitosan (CS)/poly(allylamine hydrochloride) (PAH) in different compositions were prepared as smart drug delivery matrices. The properties of these polymeric films were then explored. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis confirmed an intermolecular hydrogen bonding between CS and PAH. Atomic force microscopy (AFM) revealed improvements in surface morphology as the percentage of PAH in the blend films increased up to 60% (w/w). Water contact angle (WCA) ranged between 97° to 115°, exhibiting the hydrophobic nature of the films. Two films were selected, CTH-1 (90% CS and 10% PAH) and CTH-2 (80% CS and 20% PAH), to test for in vitro cumulative drug release (%) at 37 ± 0.5 °C as a function of time. It was revealed that for simulated gastric fluid (SGF) with pH 1.2, the cumulative drug release (CDR) for CTH-1 and CTH-2 was around 88% and 85% in 50 min, respectively. Both films converted into gel-like material after 30 min. On the other hand, in pH 7.4 phosphate buffer saline (PBS) solution, the maximum CDR for CTH-1 and CTH-2 was 93% in 90 min and 98% in 120 min, respectively. After 120 min, these films became fragments. Sustained drug release was observed in PBS, as compared to SGF, because of the poor stability of the films in the latter. These results demonstrate the excellent potential of blend films in sustained-release drug delivery systems for hydrophilic or unstable drugs.

Assessment of ecotoxicity and total volatile organic compound (TVOC) emissions from food and children's toy products

The development of new methods for identifying a broad spectrum of analytes, as well as highly selective tools to provide the most accurate information regarding the processes and relationships in the world, has been an area of interest for researchers for many years. The information obtained with these tools provides valuable data to complement existing knowledge but, above all, to identify and determine previously unknown hazards. Recently, attention has been paid to the migration of xenobiotics from the surfaces of various everyday objects and the resulting impacts on human health. Since children are among those most vulnerable to health consequences, one of the main subjects of interest is the migration of low-molecular-weight compounds from toys and products intended for children. This migration has become a stimulus for research aimed at determining the degree of release of compounds from popular commercially available chocolate/toy sets. One of main objectives of this research was to determine the impact of time on the ecotoxicity (with Vibrio fischeri bioluminescent bacteria) of extracts of products intended for children and to assess the correlation with total volatile organic compound emissions using basic chemometric methods. The studies on endocrine potential (with XenoScreen YES/YAS) of the extracts and showed that compounds released from the studied objects (including packaging foils, plastic capsules storing toys, most of toys studied and all chocolate samples) exhibit mostly androgenic antagonistic behavior while using artificial saliva as extraction medium increased the impact observed. The impact of time in most cases was positive one and increased with prolonging extraction time. The small-scale stationary environmental test chambers - μ-CTE™ 250 system was employed to perform the studies aimed at determining the profile of total volatile organic compounds (TVOCs) emissions. Due to this it was possible to state that objects from which the greatest amounts of contaminants are released are plastic containers (with emission rate falling down from 3273 to 2280 ng/g of material at 6 h of conditioning in elevated temperature).

Synthesis, properties and biomedical applications of hydrolytically degradable materials based on aliphatic polyesters and polycarbonates

Polyester-based polymers represent excellent candidates in synthetic biodegradable and bioabsorbable materials for medical applications owing to their tailorable properties. The use of synthetic polyesters as biomaterials offers a unique control of morphology, mechanical properties and degradation profile through monomer selection, polymer composition (i.e. copolymer vs. homopolymer, stereocomplexation etc.) and molecular weight. Within this review, the synthetic routes, degradation modes and application of aliphatic polyester- and polycarbonate-based biomaterials are discussed.

Effective clean-up of organic liquid contaminants including BTEX, fuels, and organic solvents from the environment by poly(alkoxysilane) sorbents

Novel cross-linked poly(alkoxysilane)s, which can be used for the removal of organic liquid contaminants from water, were synthesized in one step, in a solvent free reaction medium, at moderately high temperature without using a catalyst. The synthesized polymers were characterized by Fourier transform infrared spectroscopy (FTIR), solid-state (13)C and (29)Si cross-polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) methods and elemental analysis. The swelling features of the poly(alkoxysilane)s were investigated in organic solvents and oils, such as dichloromethane, benzene, toluene, xylene, methyl tertiary butyl ether, and also some fuel derivatives, such as gasoline and euro diesel. All polymers have high-fast solvent uptake abilities, good reusability and thermal stability. The swelling features of the synthesized cross-linked polymers were evaluated by the swelling test, absorption-desorption kinetics. Thus, the results propose that cross-linked poly(alkoxysilane)s are suitable for the absorption of oil-organic pollutants from the water surface.

In Vitro Enzymatic Degradation of Tissue Grafts and Collagen Biomaterials by Matrix Metalloproteinases: Improving the Collagenase Assay

Matrix metalloproteinase-1 and -8 are active during the wound healing and remodelling processes, degrading native extracellular matrix and implantable devices. However, traditional in vitro assays utilize primarily matrix metalloproteinase-1 to mimic the in vivo degradation microenvironment. Herein, we assessed the influence of various concentrations of matrix metalloproteinase- 1 and 8 (50, 100, and 200 U/mL) as a function of pH (5.5 and 7.4) and time (3, 6, 9, 12, and 24 h) on the degradation profile of three tissue grafts (chemically cross-linked Permacol, nonchemically cross-linked Permacol and nonchemically cross-linked Strattice) and a collagen biomaterial (nonchemically cross-linked collagen sponge). Chemically cross-linked and nonchemically cross-linked Permacol samples exhibited the highest resistance to enzymatic degradation, while nonchemically cross-linked collagen sponges exhibited the least resistance to enzymatic degradation. Qualitative and quantitative degradation analysis of all samples revealed a similar degradation profile over time, independently of the matrix metalloproteinase used and its respective concentration and pH. These data indicate that matrix metalloproteinase-1 and matrix metalloproteinase-8 exhibit similar degradation profile in vitro, suggesting that matrix metalloproteinase-8 should be used for collagenase assay.