Base Hydrolysis Research Articles

One-Pot Preparation of (NH)-Phenanthridinones and Amide-Functionalized [7]Helicene-like Molecules from Biaryl Dicarboxylic Acids.

A one-pot transformation of biaryl dicarboxylic acids to (NH)-phenanthridinone derivatives based on a Curtius rearrangement and subsequent basic hydrolysis was developed. This method is also applicable for the preparation of optically active amide-functionalized [7]helicene-like molecules. Furthermore, aza[5]helicene derivatives with a phosphate moiety were isolated as a product of the Curtius rearrangement step in the case of substrates that bear chalcogen atoms. The stereostructures of these products, revealed by X-ray diffraction analysis, suggested that chalcogen-bonding and pnictogen-bonding interactions might contribute to their stabilization. The configurational stability of the helicene-like molecules and their chiroptical properties were further investigated.

The Biological Origins of Soil Organic Matter in Different Land-Uses in the Highlands of Ethiopia

In the Ethiopian highlands, clearance of Afromontane dry forest and conversion to crop and grazing land lead to land degradation and loss of soil organic matter (SOM). Eucalyptus is often grown on degraded soils, and this results in the partial recovery of soil carbon stocks. The aim of this work was to assess the biological sources of SOM in this land-use sequence. In top-soils (0–10 cm) of four land-use systems, namely remnant natural forest, eucalyptus plantation, cropland, and grazing land, in the Ethiopian highlands, the origin of SOM was investigated. For this, a sequential extraction method was used, involving a solvent extraction, base hydrolysis, and a subsequent CuO oxidation. In these extracts, biomarkers (molecular proxies) were identified to characterize the SOM of the soil of the four land-uses. Putative lipid monomers of leaf, root, and microbial degradation products suggest that root inputs and microbial inputs dominate in SOM of all the land-uses, except grazing land. The ratios of syringyls, vanillyls, and cinnamyls showed that non-woody angiosperm plants were the predominant source for lignin in eucalyptus, cropland, and grazing land soil. In the soils of the natural forest, lignin originates from both woody angiosperms and woody gymnosperms. Our study shows the importance of root and microbial inputs in the formation of SOM, but also that, in the natural forest, legacies of previous forest cover are present.

Study of erdafitinib stress degradation behavior using HPLC-UV analysis and multistage fragmentation ion trap mass spectrometry

Erdafitinib is a fibroblast growth factor receptor inhibitor, which has been recently approved for the treatment of urothelial carcinoma. The stress degradation behavior of erdafitinib was examined using a validated stability-indicating high-performance liquid chromatography method. The study was extended to investigate the fragmentation pathways of erdafitinib using ion trap mass spectrometry. Six degradation products and an impurity were characterized depending on their multistage fragmentation pattern. The degradation products formed under different stress conditions showed molecular masses of 443, 477, 433, 479, 463, and 459. The molecular mass of the detected impurity was 525. The drug and its related substances were efficiently separated on an Eclipse Plus C18 column (4.6 × 100 mm, 3.5 µm). An isocratic mobile phase consisting of acetonitrile and 0.01 M ammonium formate in water containing 0.1% formic acid (26:74, v/v) was used at a flow rate of 0.5 mL/min. Erdafitinib was exposed to oxidative, photolytic, acidic, basic, and thermal hydrolysis as recommended by ICH guidelines. The drug was found to be more sensitive to oxidative hydrolysis and slightly sensitive to acidic and photolytic hydrolysis. The method was fully validated according to ICH guidelines. The limit of detection and quantitation were 0.2 and 0.5 µg/mL, respectively. The relative standard deviations of intraday and interday precisions were not more than 1.99%. The developed method was successfully applied for the determination of erdafitinib in bulk and laboratory-prepared tablets.

Automation System for the Flexible Sample Preparation for Quantification of Δ9-THC-D3, THC-OH and THC-COOH from Serum, Saliva and Urine

In the life sciences, automation solutions are primarily established in the field of drug discovery. However, there is also an increasing need for automated solutions in the field of medical diagnostics, e.g., for the determination of vitamins, medication or drug abuse. While the actual metrological determination is highly automated today, the necessary sample preparation processes are still mainly carried out manually. In the laboratory, flexible solutions are required that can be used to determine different target substances in different matrices. A suitable system based on an automated liquid handler was implemented. It has been tested and validated for the determination of three cannabinoid metabolites in blood, urine and saliva. To extract Δ9-tetrahydrocannabinol-D3 (Δ9-THC-D3), 11-hydroxy-Δ9-tetrahydrocannabinol (THC-OH) and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH) from serum, urine and saliva both rapidly and cost-effectively, three sample preparation methods automated with a liquid handling robot are presented in this article, the basic framework of which is an identical SPE method so that they can be quickly exchanged against each other when the matrix is changed. If necessary, the three matrices could also be prepared in parallel. For the sensitive detection of analytes, protein precipitation is used when preparing serum before SPE and basic hydrolysis is used for urine to cleave the glucuronide conjugate. Recoveries of developed methods are >77%. Coefficients of variation are <4%. LODs are below 1 ng/mL and a comparison with the manual process shows a significant cost reduction.

Surface chemistry of metal oxide nanoparticles: NMR and TGA quantification

Surface functionalization is widely used to control the behavior of nanomaterials for a range of applications. However, methods to accurately quantify surface functional groups and coatings are not yet routinely applied to nanomaterial characterization. We have employed a combination of quantitative NMR (qNMR) and thermogravimetric analysis (TGA) to address this problem for commercial cerium, nickel, and iron oxide nanoparticles (NPs) that have been modified to add functional coatings with (3-aminopropyl)triethoxysilane (APTES), stearic acid, and polyvinylpyrrolidone (PVP). The qNMR method involves quantification of material that is released from the NPs and quantified in the supernatant after removal of NPs. Removal of aminopropylsilanes was accomplished by basic hydrolysis whereas PVP and stearic acid were removed by ligand exchange using sodium hexametaphosphate and pentadecafluorooctanoic acid, respectively. The method accuracy was confirmed by analysis of NPs with a known content of surface groups. Complementary TGA studies were carried out in both air and argon atmosphere with FT-IR of evolved gases in argon to confirm the identity of the functional groups. TGA measurements for some unfunctionalized samples show mass loss due to unidentified components which makes quantification of functional groups in surface-modified samples less reliable. XPS provides information on the presence of surface contaminants and the level of surface hydroxylation for selected samples. Despite the issues associated with accurate quantification using TGA, the TGA estimates agree reasonably well with the qNMR data for samples with high surface loading. This study highlights the issues in analysis of commercial nanomaterials and is an advance towards the development of generally applicable methods for quantifying surface functional groups.Graphical abstract

Improvement of the Hydrolytic Stability of the Keggin Molybdo- and Tungsto-Phosphate Anions by Cyclodextrins.

Keggin-type molybdo- and tungsto-phosphate polyoxoanions are among the most popular polyoxometalates (POMs) but suffer from their limited stability at low pH in aqueous solution. Their superchaotropic properties generate strong supramolecular complexes with cyclodextrins (CDs), which significantly affect the hydrolytic stability of POM. This chaotropically driven stabilization effect was systematically monitored by 31P NMR spectroscopy covering a wide range of pH (from 0 to 8) and varying the nature of the CD (α-, β-, and γ-form). A shift of ca. two pH units of the stability domains of these POMs was found in the presence of two equivalents of γ-CD compared to pure water, leading to keep intact the PW12O403- anion without any decomposition up to pH 3.5 (versus 1.5 in pure water) and pH 2.5 for PMo12O403-, which begins to decompose even at pH 0 in pure water. The effect of the smaller CDs (α- and β-form) is much less pronounced (only 0.5 pH units shift of the stability domain) confirming the importance of host-guest size matching to form a sandwich-type inclusion complex and thus protect the POM structure against basic hydrolysis. Such complexation was further supported by 183W and 1H NMR spectroscopy. Finally, using quantitative 31P NMR analyses, the new speciation and formation constants of phospho-molybdates and phospho-tungstates in the presence of cyclodextrins are determined and compared to those previously reported in pure water or in the 50:50 water/1,4-dioxane mixture.

Identification and characterization of urapidil stress degradation products by LC-Q-TOF-MS and NMR: Toxicity prediction of degradation products

Urapidil, an antihypertensive drug is subjected to various stress conditions (acidic, basic, neutral, oxidative and photolytic) as per ICH guidelines. A stability indicating HPLC method was developed using InertSustain C8 (250 × 4.6 mm; 5 µm) column and 10 mM ammonium formate (pH 3.5) with gradient elution at a flow rate of 1 mL/min to separate all the DPs. The drug was susceptible to acidic and basic hydrolysis, oxidative and photolytic stress conditions in the solution phase and stable in neutral solution phase and photolytic solid state conditions. A total of five DPs were detected under different stress conditions including DP4 which was previously reported in the literature. An extensive fragmentation pattern of drug and DPs were established using LC-Q-TOF-MS which aided the characterization of DPs. The ambiguity in the position of N-oxide formation in DP5 was confirmed by NMR studies. In silico toxicity of the drug and its DPs were also evaluated. The plausible mechanism of DPs formation was explained.

Study on Stress Degradation Behaviour of Abiraterone Acetate in Film Coated Tablets and Identification of Major Stress Degradation Product by LC-UV-ESI-MS

Abiraterone acetate is an androgen biosynthesis inhibitor used in the treatment of prostate cancer. This study focuses on a simple, economical and systematic liquid chromatographic and mass spectroscopic method to study the stress degradation behavior of abiraterone acetate under various stress conditions along with its validation. The chromatographic separation of abiraterone acetate and its major degradation product is achieved on Capcell PAK C18 MG-III (100×4.6 mm, 3 μm) column using combination of 0.1 % acetic acid and acetonitrile as mobile phase with a flow rate of 1.2 ml/min and the wavelength of detection is selected as 251 nm. The drug was degraded extensively in acidic and basic hydrolysis. A tentative degradation pathway of drug in acidic and alkaline condition was predicted. The developed analytical method was found selective, accurate, precise and robust in accordance with International Council for Harmonization guidelines. The method will also suffice the suitability for the assay of abiraterone acetate in bulk and finished products.

Photophysics of tetracarboxy-zinc phthalocyanine photosensitizers.

Zinc-tetracarboxy-phthalocyanine (ZnPc(COOH)4) was synthesized by a melting method and basic hydrolysis. A ZnPc(COOH)4/Fe3O4/Ch composite was prepared by immobilization of ZnPc(COOH)4 onto Fe3O4/chitosan nanoparticles by a simple immersion method. The photophysical properties were studied using UV-vis spectrophotometry, fluorescence spectroscopy and time-correlated single photon counting (TCSPC) in different aqueous solutions. The UV-vis spectra of the ZnPc(COOH)4/Fe3O4/Ch composite displays absorption by the aromatic rings, with a Q band exhibited at λ max = 702 nm. Moreover, the ZnPc(COOH)4/Fe3O4/Ch composite exhibits long triplet-state lifetimes of 1.6 μs and 12.3 μs, crucial for application as a photosensitizer. A triplet quantum yield of 0.56 for the ZnPc(COOH)4/Fe3O4/Ch composite in DMSO/H2O was achieved. FTIR showed that the conjugation of ZnPc(COOH)4 with Fe3O4/chitosan nanoparticles was achieved by electrostatic interaction.

Analytical method development and validation for the determination of Flibanserin using reverse phase HPLC method

Flibanserin (Addyi) is a medication used to treat women who have not gone through menopause who have low sexual desire. Specific and simple stability indicating method was developed and validated by high-performance liquid chromatography (RP-HPLC) for the determination of Flibanserin. Separation was carried out by using a mobile phase consisting of 0.01M Potassium phosphate monohydrate buffer (KH2PO4) pH 3.50 buffer: Acetonitrile in the ratio of 60:40. The column used was Agilent C18, (150×4.6) mm, 5µm with a flow rate of 1.0ml/min and temperature at 30°C. The detection was carried out at 248 nm and Flibanserin was eluted at around 2.8min. This method was validated as per ICH guidelines and validation included specificity, precision, linearity, accuracy, forced degradation, and robustness. Forced degradation was conducted under the conditions of hydrolysis, oxidation, thermal, acid, base, and peroxide hydrolysis. The calibration curve was linear over the concentration range from 20 to 200µg/mL and the coefficient of determination (r2) was observed as 0.9998. The precision and accuracy of the method were within the acceptable range. The results of this study showed that the validated method is simple and accurate, which confirmed that the method is suitable for the determination of Flibanserin.

Forced Degradation Study of Zanubrutinib: An LC-PDA and LC-MS Approach.

Zanubrutinib is an unfamiliar second generation selective Brutson's Tyrosine Kinase inhibitor used to treat mantle cell lymphoma. In the present analysis, a new, stability indicating reverse-phase, high performance liquid chromatography method was developed and validated for the determination of Zanubrutinib succeeding degradation studies as pert the International Conference on Harmonization guidelines. The chromatographic separation of Zanubrutinib was achieved in a C18 column (250 × 4.6mm, 5-μm particle size) using a mobile phase of Acetonitrile: 0.1% Tri Ethyl Amine (65:35v/v) monitored at 219nm. The forced degradation studies were conducted by exposing the analyte to acidic, alkaline and neutral hydrolysis, oxidative, reductive, photolytic, and thermal stress conditions and the degradation behavior was studied. The analyte showed degradation under acidic, alkaline, oxidative and reductive stress conditions with additional peaks but, it was stable under neutral, photolytic and thermal stress conditions. The developed method was extended to triple quadruple mass spectrometry to characterize degradation products and to study the fragmentation pattern. Total four degradants were characterized including DP1 in acid &base hydrolysis, DP2 in oxidative and DP3, DP4 in reductive stress condition. As no substantial method was available for quantification of Zanubrutinib and to characterize zanubrutinib degradants, this method can be used for regular analysis in quality control labs.

ASSESSMENT OF PHENOLIC COMPOUNDS, ANTIMICROBIAL ACTIVITY AND FREE RADICAL SCAVENGING POTENCY OF THREE SELECTED VEGETABLES

Phytochemicals are compounds derived from plants that are assumed to have defensive role against certain disease. They have antioxidants, anticancer, antimicrobial, antifungal, antiviral, antithrombic and anti-inflammatory properties. They have a high specificity to boost the immune system and play important role in the metabolism of hormones. The current study is based on qualitative and quantitative evaluation of total phenolics contents, phenolic compounds, antioxidant potential, free and bound phenolic acids in selected vegetables available at the local market of Hyderabad, Sindh, Pakistan. Two different extraction procedures ultrasonic-assisted base hydrolysis extraction and sonication extraction were used. Total 13 phenolic compounds were found and quantified by high-performance liquid chromatography (HPLC), in which Ferulic acid was quantified in a higher amount of 16.71 mg/g in bitter gourd. Total phenolic contents were determined by using Perklin-Elmer lambda UV/Visible spectrophotometer and higher concentration was found in Bitter gourd 92.56 mg 100/g as compared to Luffa and Brinjal with 79.03 and 66.56 mg 100/g, respectively. The antioxidant activity (DPPH assay) was measured at ?max of 517 nm, results revealed that Bitter gourd possessed the higher antioxidant activity with 182.61 µMol/g followed by Luffa and Brinjal with 112.94 and 82.96 µMol/g. The total Flavonoid contents were higher in Brinjal with 44.32 mg g-1 whereas Luffa and Bitter gourd possess the Flavonoid concentration in the range 38.02 and 34.64mg g-1 respectively, the total tannin contents also higher in Brinjal 31.40 mg/g follwed by in Luffa and Bitter gourd with 25.17 and 21.19 mg/g respectively. Antimicrobial activity showed that, all the extracts are the highly effective against S. aureus as compared to E. coli. Finally, it is concluded that all the selected vegetables are very good sources of Phenolic compounds as well as phytochemicals and should be included in the daily human diet for good health. On the basis of obtained results, it is also suggested that these samples will be further investigated for the determination of fatty acids by GC-MS and liquid chromatography-mass spectrum (LC-MS).

Forced Degradation Study for Simultaneous Quantification of Aspirin and Omeprazole in Pharmaceutical Dosage form by RP-HPLC

Aims: To study force degradation of aspirin and omeprazole simultaneously by RP-HPLC method
 Study design: RP-HPLC method was used to measure % degradation.
 Place and Duration of Study: Study was carried out at center of excellence, G.I.D.C., vapi-396195, Gujarat, India between June 2019 to march 2020.
 Methodology: A force degradation study of aspirin and omeprazole was carried out simultaneously. The drugs were subjected to various degradation conditions like hydrolysis by acid and base, Oxidative degradation, and thermal degradation study.
 Results: For acidic condition, the degradation was found to be 32.63 % for aspirin and 61.64 % for omeprazole. For basic condition, the degradation was found to be 10.17 % for aspirin and 4.29 % for omeprazole. By oxidative hydrolysis, the aspirin was degraded by 15.48 % and omeprazole was degraded by 26.38 %. By thermal degradation, 0.37 % degradation was observed for aspirin and 4.32 % degradation for omeprazole.
 Conclusion: In this proposed method the retention time for drug is less than 8 min, which is less then available method. For omeprazole, strong degradation was observed in acidic conditions and mild in basic hydrolysis conditions. For aspirin, more degradation was observed in basic conditions than acidic hydrolysis. Both drugs were degraded in oxidative conditions using 3% H2O2. Omeprazole degraded more than aspirin by dry heat degradation. The method was successfully applied for the quantitative determination of both Active Pharmaceutical Ingredients.

Separation and Characterization of the Related Substances of Bedaquiline Fumarate Using HPLC and Spectral Methods

The study focuses on isolating and characterizing the potential degradation products (DPs) and impurities of Bedaquiline fumarate in bulk drug form. A stability-indicating related substance method was developed and validated using high-performance liquid chromatography. Agilent Poroshell 120EC- C18 (150mm × 4.6mm, 2.7μm) column showed an optimum separation of 10 analytes. The mobile phase contained 0.05% trifluoroacetic acid, acetonitrile and methanol in a time gradient mode. Bedaquiline fumarate was susceptible to acid hydrolysis, oxidation, base hydrolysis and showed three potential DPs, including DP-1, DP-2 and Impurity-8. Degradation products, DP-1 and DP-2, were isolated and characterized by ESI-MS, 1H, NMR and 13C NMR spectroscopy. The developed method was validated according to ICH tripartite guidelines and showed adequate specificity, accuracy and linearity. The limit of detection and limit of quantitation were 0.05 and 0.15μg/mL, respectively.

Development and Validation of a Stability-Indicating HPLC Method for the Simultaneous Determination of trans-Resveratrol and cis-Resveratrol in an Injectable Solution.

trans-Resveratrol, a phytochemical compound with antioxidant power and various therapeutic effects, such as cardioprotective, chemopreventive, and neuroprotective, among others, has disadvantages of poor solubility and limited stability, creating difficulties for the development of new strategies for its quantification. This study developed and validated an analytical stability method for trans-resveratrol by high-pressure liquid chromatography with photodiode-array detection (HPLC-PDA), which allowed its quantification in the presence of its degradation products. The quantification of trans-resveratrol occurred at a retention time of 2.6 min, with ammonium formate (10 mM, pH = 4)/acetonitrile, 70/30 v/v, as mobile phase. The validation met the ICH Q2 criteria of specificity, method linearity (2.8–4.2 μg/ml), precision and accuracy, robustness, quantification limit (0.176 μg/ml), and detection (0.058 μg/ml). As degradation products, cis-resveratrol was observed at 3.9 min, which could be resveratrone in 3.2 min and five unidentified products in 0.7, 1.0, 1.4, 1.8, and 5 min. Some solutions subjected to temperature stress of 40 and 60°C, UV light, and acidic and basic hydrolysis exhibited colour changes. An analytical method was obtained by HPLC-PDA, which allowed quantifying the stability of trans-resveratrol in a fast and specific manner in the presence of its degradation products.

A novel stability-indicating HPLC-DAD method for determination of favipiravir, a potential antiviral drug for COVID-19 treatment; application to degradation kinetic studies and in-vitro dissolution profiling

Modern pharmaceutical analysis is paying a lot of attention to the stability of novel drug formulations as well as establishment of suitable stability-indicating approaches. In the current work, a comprehensive stability-indicating HPLC-DAD method has been developed and validated for determination of favipiravir (FAV) which is a novel and emerging antiviral option in COVID-19 treatment. The stability of FAV was examined under different stress conditions. FAV was found to be susceptible to acid, base hydrolysis and oxidative degradation. Structure elucidation of the forced degradation products was carried out using mass spectrometry (MS) operated in electrospray ionization mode. Effective separation of FAV and its induced degradation products was achieved using isocratic elution mode on Zorbax C18 column maintained at 30 °C. The mobile phase used was comprised of 25.0 mM phosphate buffer (pH 3.5 ± 0.05) containing 0.1% (w/v) heptane sulphonic acid sodium salt-methanol–acetonitrile (62:28:10, by volume), delivered at flow rate of 1.0 mL/min. The diode array detector signal for FAV was monitored at 321.0 nm over a concentration range of 6.25–250.00 µg/mL. The potential mechanisms for generation of degradation products were postulated through comparison of MS1 fragmentation pattern of FAV and its degradation products. Moreover, the proposed method was also extended to study the degradation kinetics. Additionally, dissolution profiling of FAV in different media was monitored. Clearly, the suggested approach is accurate, reliable, time-saving, and cost-effective. As a result, it may be utilized for regular quality control and stability assessment of FAV in its tablet dosage form.

Revisiting Jatropha curcas Monomeric Esterase: A Dienelactone Hydrolase Compatible with the Electrostatic Catapult Model.

Jatropha curcas contains seeds with a high oil content, suitable for biodiesel production. After oil extraction, the remaining mass can be a rich source of enzymes. However, data from the literature describing physicochemical characteristics for a monomeric esterase from the J. curcas seed did not fit the electrostatic catapult model for esterases/lipases. We decided to reevaluate this J. curcas esterase and extend its characterization to check this apparent discrepancy and gain insights into the enzyme’s potential as a biocatalyst. After anion exchange chromatography and two-dimensional gel electrophoresis, we identified the enzyme as belonging to the dienelactone hydrolase family, characterized by a cysteine as the nucleophile in the catalytic triad. The enzyme displayed a basic optimum hydrolysis pH of 9.0 and an acidic pI range, in contrast to literature data, making it well in line with the electrostatic catapult model. Furthermore, the enzyme showed low hydrolysis activity in an organic solvent-containing medium (isopropanol, acetonitrile, and ethanol), which reverted when recovering in an aqueous reaction mixture. This enzyme can be a valuable tool for hydrolysis reactions of short-chain esters, useful for pharmaceutical intermediates synthesis, due to both its high hydrolytic rate in basic pH and its stability in an organic solvent.

Low Polarity-Triggered Basic Hydrolysis of Coumarin as an AND Logic Gate for Broad-Spectrum Cancer Diagnosis.

The ability to accurately diagnose cancer is the cornerstone of early cancer treatment. The mitochondria in cancer cells maintain a higher pH and lower polarity relative to that in normal cells. A probe that reports signals only when both conditions are met may provide a reliable method for cancer detection with reduced false positives. Here, we construct an AND logic gate fluorescent probe using mitochondrial microenvironments as inputs. Utilizing the hydrolysis of a coumarin scaffold, the probe generates fluorescence signals ("ON") only when high pH (>7.0) and low polarity conditions exist simultaneously. Additionally, the higher mitochondrial membrane potential in cancer cells provides an additional level of selectivity because probe has increased affinity for cancer cell mitochondria. These capabilities endow the probe with a high contrast fluorescence diagnosis ability of cancer at cellular and tissue levels (as high as 51.9 fold), which is far exceeding the clinic threshold of 2.0 fold.

Two-step continuous flow synthesis of α-terpineol

α-Terpineol is a naturally occurring monoterpene present in essential oils, of high value on the market as it is widely used as flavoring in the cosmetics and food industry. This study aims to produce α-terpineol by two different synthetic strategies, using both batch and continuous flow systems, focusing on the optimization of the process, improving the reaction conversion and selectivity. The first strategy adopted was a one-stage hydration reaction of (+)-α-pinene by an aqueous solution of chloroacetic acid (molar ratio 1:1 between pinene and the acid) in continuous flow conditions. This reaction was carried out at 80 °C with a residence time of 15 min, obtaining good conversion (72%) and selectivity (76%), and productivity of 0.53 kg.day−1. The second strategy accomplished was a two-step cascade reaction with (+)-limonene as starting material, where the first step is a chemospecific double bond addition using trifluoroacetic acid, and the second step is the basic hydrolysis of the ester promoted by a solution of sodium hydroxide (2.25 M) in methanol (1:1). This reaction was adapted to a continuous flow condition, where all steps involved a residence time of 40 min, at 25 °C, with no quenching between steps required, with 97% conversion, 81% selectivity and up to 0.14 kg.day−1.

Properties and Degradation Performances of Biodegradable Poly(lactic acid)/Poly(3-hydroxybutyrate) Blends and Keratin Composites.

From environmental aspects, the recovery of keratin waste is one of the important needs and therefore also one of the current topics of many research groups. Here, the keratin hydrolysate after basic hydrolysis was used as a filler in plasticized polylactic acid/poly(3-hydroxybutyrate) blend under loading in the range of 1–20 wt%. The composites were characterized by infrared spectroscopy, and the effect of keratin on changes in molar masses of matrices during processing was investigated using gel permeation chromatography (GPC). Thermal properties of the composites were investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The effect of keratin loading on the mechanical properties of composite was investigated by tensile test and dynamic mechanical thermal analysis. Hydrolytic degradation of matrices and composites was investigated by the determination of extractable product amounts, GPC, DSC and NMR. Finally, microbial growth and degradation were investigated. It was found that incorporation of keratin in plasticized PLA/PHB blend provides material with good thermal and mechanical properties and improved degradation under common environmental conditions, indicating its possible application in agriculture and/or packaging.