RESUMO
In this work, monodisperse and nano-porous poly(bismaleimide-co-divinylbenzene) microspheres with large specific surface area (427.6 m2 /g) and rich pore structure were prepared by one-pot self-stable precipitation polymerization of 2,2'-bis[4-(4-maleimidophenoxy) phenyl] propane and divinylbenzene. The prepared poly(bismaleimide-co-divinylbenzene) microspheres were employed as dispersive solid-phase extraction (DSPE) adsorbent for the extraction of triazine herbicides. Under optimized conditions, good linearities were obtained between the peak area and the concentration of triazine herbicides in the range of 1-400 µg/L (R2 ≥ 0.9987) with the limits of detection of 0.12-0.31 µg/L. Triazine herbicides were detected using the described approach in vegetable samples (i.e., cucumber, tomato, and maize) with recoveries of 93.6%-117.3% and relative standard deviations of 0.4%-3.5%. In addition, the recoveries of triazine herbicides remained above 80.7% after being used for nine DSPE cycles, showing excellent reusability of poly(bismaleimide-co-divinylbenzene) microspheres. The adsorption of poly(bismaleimide-co-divinylbenzene) microspheres toward triazine herbicides was a monolayer and chemical adsorption. The adsorption mechanism between triazine herbicides and adsorbents might be a combination of hydrogen bonding, electrostatic interaction, and π-π conjugation. The results confirmed the potential use of the poly(bismaleimide-co-divinylbenzene) microspheres-based DSPE coupled to the high-performance liquid chromatography method for the detection of triazine herbicide residues in vegetable samples.
Assuntos
Herbicidas , Verduras , Compostos de Vinila , Verduras/química , Cromatografia Líquida de Alta Pressão/métodos , Microesferas , Porosidade , Triazinas/análise , Extração em Fase Sólida/métodos , Herbicidas/análise , Limite de DetecçãoRESUMO
To inhibit viral infection, it is necessary for the surface of polypropylene (PP), a polymer of significant industrial relevance, to possess biocidal properties. However, due to its low surface energy, PP weakly interacts with other organic molecules. The biocidal effects of quaternary ammonium compounds (QACs) have inspired the development of nonwoven PP fibers with surface-bound quaternary ammonium (QA). Despite this advancement, there is limited knowledge regarding the durability of these coatings against scratching and abrasion. It is hypothesized that the durability could be improved if the thickness of the coating layer were controlled and increased. We herein functionalized PP with three-dimensionally surface-grafted poly(N-benzyl-4-vinylpyridinium bromide) (PBVP) by a simple and rapid method involving graft polymerization and benzylation and examined the influence of different factors on the antiviral effect of the resulting plastic by using a plaque assay. The thickness of the PBVP coating, surface roughness, and amount of QACs, which jointly determine biocidal activity, could be controlled by adjusting the duration and intensity of the ultraviolet irradiation used for grafting. The best-performing sample reduced the viral infection titer of an enveloped model virus (bacteriophage Ï6) by approximately 5 orders of magnitude after 60 min of contact and retained its antiviral activity after surface polishing-simulated scratching and abrasion, which indicated the localization of QACs across the coating interior. Our method may expand the scope of application to resin plates as well as fibers of PP. Given that the developed approach is not limited to PP and may be applied to other low-surface-energy olefinic polymers such as polyethylene and polybutene, our work paves the way for the fabrication of a wide range of biocidal surfaces for use in diverse environments, helping to prevent viral infection.
Assuntos
Polipropilenos , Polivinil , Compostos de Piridínio , Compostos de Vinila , Viroses , Humanos , Polipropilenos/farmacologia , Compostos de Amônio Quaternário/farmacologia , Polímeros/farmacologia , Antivirais/farmacologiaRESUMO
Due to growing concerns about environmental pollution from plastic waste, plastic recycling research is gaining momentum. Traditional methods, such as incorporating inorganic particles, increasing cross-linking density with peroxides, and blending with silicone monomers, often improve mechanical properties but reduce flexibility for specific performance requirements. This study focuses on synthesizing silica nanoparticles with vinyl functional groups and evaluating their mechanical performance when used in recycled plastics. Silica precursors, namely sodium silicate and vinyltrimethoxysilane (VTMS), combined with a surfactant, were employed to create pores, increasing silica's surface area. The early-stage introduction of vinyl functional groups prevented the typical post-synthesis reduction in surface area. Porous silica was produced in varying quantities of VTMS, and the synthesized porous silica nanomaterials were incorporated into recycled polyethylene to induce cross-linking. Despite a decrease in surface area with increasing VTMS content, a significant surface area of 883 m2/g was achieved. In conclusion, porous silica with the right amount of vinyl content exhibited improved mechanical performance, including increased tensile strength, compared to conventional porous silica. This study shows that synthesized porous silica with integrated vinyl functional groups effectively enhances the performance of recycled plastics.
Assuntos
Nanopartículas , Nanoestruturas , Silanos , Compostos de Vinila , Dióxido de Silício , Reciclagem , Poluição AmbientalRESUMO
We are looking into how well a copolymeric material made of poly (maleic acid-co-4-vinylpyridine) cross-linked with divinylbenzene can separate L-norepinephrine (L-NEP) from (±)-NEP. The initial step in this direction was the synthesis and subsequent analysis of L-NEP-maleimide chiral derivative. A 4-vinylpyridine/divinylbenzene combination was copolymerized with the resultant chiral maleimide. After heating the polymer materials in a high-alkaline environment to breakdown the connecting imide bonds, they were acidified in an HCl solution to eliminate the incorporated L-NEP species. Fourier transform infrared spectroscopy (FTIR) and a scanning electron microscope were used to examine the imprinted L-NEP-imprinted materials. The manufactured L-NEP-imprinted materials exhibited selectivity characteristics that were over 11 times greater for L-NEP than D-norepinephrine. The highest capacity observed in Langmuir adsorption studies was 170 mg/g at a pH of 7. After optical separation using a column technique, it was determined that the enantiomeric excess levels of D-norepinephrine and L-NEP in the first feeding and subsequent recovery solutions were 95% and 81%, respectively.
Assuntos
Impressão Molecular , Polímeros Molecularmente Impressos , Compostos de Vinila , Norepinefrina , Impressão Molecular/métodos , Estereoisomerismo , Polímeros/química , Adsorção , MaleimidasRESUMO
The current study focuses on the development of a superhydrophobic poly(vinylidene fluoride-cohexafluoropropylene) nanocomposite membrane suitable for vacuum membrane distillation by incorporating SiO2 nanoparticles. At loading hydrophobic nano-SiO2 particle concentration (0.50-1.50 wt.%), the developed nanocomposite membranes are optimized in terms of vacuum membrane distillation performance. The influence of temperature, vacuum pressure, and feed water flow is studied for desalinating high-salinity brine. The results show that the developed vacuum distillation membrane is capable of 95% salt rejection during the treatment of a highly saline feed (65,000 ppm) at fixed flow rates of 120 L/h saline feed and different operating conditions consisting of feed inlet temperatures ranging from 40°C to 70°C and distillate inlet temperatures of 7-15°C. The vacuum membrane distillation process achieves 0.38-1.66% water recovery with increasing concentration factor, meaning that recovery is increased, and shows a specific electrical energy consumption of 5.16-23.90 kWh/m3 for product water. Overall, the newly designed membrane demonstrates suitability for a vacuum membrane distillation system. PRACTITIONER POINTS: Desalinate high-salinity brine (TDS > 35,000 ppm) using a vacuum membrane distillation system. A hydrophobic PVDF-HFP/SiO2 nanocomposite membrane development for vacuum membrane distillation. A newly designed single vacuum membrane distillation system for RO brine treatment.
Assuntos
Destilação , Polímeros de Fluorcarboneto , Nanopartículas , Polivinil , Sais , Compostos de Vinila , Dióxido de Silício , Vácuo , ÁguaRESUMO
Diseases and diagnoses are predominant in the human population. Early diagnosis of etiological agents plays a vital role in the treatment of bacterial infections. Existing standard diagnostic platforms are laborious, time-consuming, and require trained personnel and cost-effective procedure, though they are producing promising results. These shortcomings have led to a thirst for rapid diagnostic procedures. Fluorescence-based diagnosis is one of the efficient rapid diagnostic methods that rely on specific and sensitive bacterial detection. Emerging bio-sensing studies on conducting polymers (CPs) are gaining popularity in medical diagnostics due to their promising properties of high fluorescence efficiency, good light stability, and low cytotoxicity. Poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), is the first identified soluble polymer and model material for understanding the fundamental photophysics of conventional CPs. In this present study, MEH-PPV is used as a fluorescent dye for direct pathogen detection applications by interacting with the microbial cell surface. An optimized concentration of MEH-PPV solution used to confirm the presence of selective bacterial structures. The present study endeavours towards bacterial detection based on the emission from bacteria due to interfacial interaction between polymer and bacterial surface.
Assuntos
Polímeros , Compostos de Vinila , Humanos , Compostos de Vinila/química , Polímeros/química , Corantes Fluorescentes/químicaRESUMO
The R3m molecular descriptor (R-GETAWAY third-order autocorrelation index weighted by the atomic mass) has previously been shown to encode molecular attributes that appear to be physically and chemically relevant to grouping diverse active pharmaceutical ingredients (API) according to their potential to form persistent amorphous solid dispersions (ASDs) with polyvinylpyrrolidone-vinyl acetate copolymer (PVPVA). The initial R3m dispersibility model was built by using a single three-dimensional (3D) conformation for each drug molecule. Since molecules in the amorphous state will adopt a distribution of conformations, molecular dynamics simulations were performed to sample conformations that are probable in the amorphous form, which resulted in a distribution of R3m values for each API. Although different conformations displayed R3m values that differed by as much as 0.4, the median of each R3m distribution and the value predicted from the single 3D conformation were very similar for most structures studied. The variability in R3m resulting from the distribution of conformations was incorporated into a logistic regression model for the prediction of ASD formation in PVPVA, which resulted in a refinement of the classification boundary relative to the model that only incorporated a single conformation of each API.
Assuntos
Polímeros , Povidona , Polímeros/química , Povidona/química , Compostos de Vinila/química , Liberação Controlada de Fármacos , Solubilidade , Composição de Medicamentos/métodosRESUMO
Twin-screw extrusion is one of the major technologies for solid dispersion in the pharmaceutical industry. However, the thermal exposure to the drug during extrusion can easily trigger and exacerbate drug degradation. A conventional method for investigating drug degradation in extrusion is trial-and-error, which can consume much time and material. We propose to model drug degradation kinetics and combine it with thermal history simulation to predict drug degradation. Ritonavir and copovidone were used as a model system of solid dispersion. Hydantoin aminoalchol was the major degradant of RTV in extrudate. In studying the RTV degradation kinetics, only in nitrogen atmosphere, RTV degradation pathway in TGA or DSC was like the degradation pathway in extrusion. The mixing and solubilization of RTV in copovidone also prevented RTV from degrading to oxazolidine derivative. The degradation samples were collected at various temperatures and at different times. The data was fitted into first-order kinetics model to get degradation rates constant at each temperature. The degradation rate constants were fitted into the Arrhenius equation with an activation energy of 159.3 kJ/mol, and a pre-exponential of 1.23 × 1017. An array of extrusion conditions was developed and analyzed via design of experiment (DOE). Relying on the measured melt temperature and residence time after kneading element and die, we simulated the thermal history in the section between kneading element and die. The RTV degradation kinetics in conjunction with simulated thermal history predicted degradation and achieved a 78% regression.
Assuntos
Química Farmacêutica , Temperatura Alta , Química Farmacêutica/métodos , Pirrolidinas , Compostos de Vinila , Ritonavir , Solubilidade , Composição de Medicamentos/métodosRESUMO
Herein, we reported a transition-metal-free three-component trifluoromethyl heteroarylation of vinyl ethers under visible light irradiation. This protocol proceeded through a radical addition/cyclization sequence which hinged on the intrinsic nucleo/electrophilic reactivity of both the radicals, alkene, and alkynones, allowing ß-trifluoromethyl alkyl thiochromones furnished with high efficiency and excellent functional group tolerance. By virtue of this procedure, three distinct chemical bonds including C(sp2)-C(sp3), C(sp3)-C(sp3), and C(sp2)-S have been successively forged in a single pot.
Assuntos
Metais , Compostos de Vinila , Ciclização , Luz , ÉteresRESUMO
Terminal alkynes with a silyl group at the propargylic position upon activation with electrophiles such as N-bromosuccinimide undergo (E)-selective 1,2-silyl group migration. Subsequently, an allyl cation is formed that is intercepted by an external nucleophile. This approach provides allyl ethers and esters with stereochemically defined vinyl halide and silane handles for further functionalization. The scope of propargyl silanes and electrophile-nucleophile pairs are investigated, and various trisubstituted olefins are prepared in up to 78% yield. The obtained products have been demonstrated to serve as building blocks for transition-metal-catalyzed cross-couplings of vinyl halides, silicon-halogen exchange, and allyl acetate functionalization reactions.
Assuntos
Alcenos , Silanos , Catálise , Compostos de Vinila , ÉteresRESUMO
A fully heterogeneous metallaphotocatalytic C-C cross-coupling of aryl/vinyl halides with alkyl/allyltrifluoroborates has been developed by employing integrated bipyridyl-Ni(II)-carbon nitride as a stable and recyclable bifunctional catalyst. This visible-light-mediated heterogeneous protocol allows for the sustainable synthesis of diverse valuable diarylmethanes and allylarenes in high efficiency.
Assuntos
2,2'-Dipiridil , Compostos de Vinila , Estrutura Molecular , CatáliseRESUMO
4-Vinylcyclohexene diepoxide (VCD) is a hazardous industrial material which is widely used in the production of fragrances, rubber tires, antioxidants, pesticides, flame retardants and plasticizers. Previous studies have shown that exposure to VCD damages the female reproductive system, but the effects and mechanisms of VCD exposure on human granulosa cells are not reported. In this study, we used a human granulosa cell line (SVOG) to explore the effects of VCD exposure and found that VCD exposure had toxic effects on SVOG cells in vitro. VCD exposure led to excessive accumulation of intracellular ROS, caused DNA damage in cells, altered the expression of some key genes related with apoptosis and oxidative stress, and ultimately inhibited the proliferative capacity of granulosa cells, resulting in increased apoptosis. Overall, our findings provide solid evidence showing that VCD exposure produces severe damage to human granulosa cells, which is helpful for understanding the reproductive toxicity of VCD and etiology of infertility.
Assuntos
Cicloexenos , Células da Granulosa , Humanos , Feminino , Espécies Reativas de Oxigênio , Cicloexenos/toxicidade , Compostos de Vinila/toxicidade , Apoptose , Dano ao DNARESUMO
Although gel polymer electrolytes (GPEs) represent a promising candidate to address the individual limitations of liquid and solid electrolytes, their extensive development is still hindered due to the veiled Li-ion conduction mechanism. Herein, the related mechanism in GPEs is extensively studied by developing an in situ polymerized GPE comprising fluoroethylene carbonate (FEC) solvent and carbonate ester segments (F-GPE). Practically, although with high dielectric constant, FEC fails to effectively transport Li ions when acting as the sole solvent. By sharp contrast, F-GPE demonstrates superior electrochemical performances, and the related Li-ion transfer mechanism is investigated using molecular dynamics simulations and 7 Li/6 Li solid-state nNMR spectroscopy. The polymer segments are extended with the swelling of FEC, then an electron-delocalization interface layer is generated between abundant electron-rich groups of FEC and the polymer ingredients, which works as an electron-rich "Milky Way" and facilitates the rapid transfer of Li ions by lowering the diffusion barrier dramatically, resulting in a high conductivity of 2.47 × 10-4 S cm-1 and a small polarization of about 20 mV for Li//Li symmetric cell after 8000 h. Remarkably, FEC provides high flame-retardancy and makes F-GPE remains stable under ignition and puncture tests.
Assuntos
Eletrólitos , Compostos de Vinila , Carbonatos , Géis , Lítio , PolímerosRESUMO
Despite the recent success of amorphous solid dispersions (ASDs) at enabling the delivery of poorly soluble small molecule drugs, ASD-based dosage forms are limited by low drug loading. This is partially due to a sharp decline in drug release from the ASD at drug loadings surpassing the 'limit of congruency' (LoC). In some cases, the LoC is as low as 5% drug loading, significantly increasing the risk of pill burden. Despite efforts to understand the mechanism responsible for the LoC, a clear picture of the molecular processes occurring at the ASD/solution interface remains elusive. In this study, the ASD/solution interface was studied for two model compounds formulated as ASDs with copovidone. The evolution of a gel layer and its phase behavior was captured in situ with fluorescence confocal microscopy, where fluorescent probes were added to label the hydrophobic and hydrophilic phases. Phase separation was detected in the gel layer for most of the ASDs. The morphology of the hydrophobic phase was found to correlate with the release behavior, where a discrete phase resulted in good release and a continuous phase formed a barrier leading to poor release. The continuous phase formed at a lower drug loading for the system with stronger drug-polymer interactions. This was due to incorporation of the polymer into the hydrophobic phase. The study highlights the complex molecular and phase behavior at the ASD/solution interface of copovidone-based ASDs and provides a thermodynamic argument for qualitatively predicting the release behavior based on drug-polymer interactions.
Assuntos
Polímeros , Compostos de Vinila , Solubilidade , Liberação Controlada de Fármacos , Compostos de Vinila/química , Preparações Farmacêuticas , Polímeros/química , Composição de Medicamentos/métodosRESUMO
Monolithic poly(2-vinylnaphthalene-co-divinylbenzene) columns were introduced, for the first time, and were evaluated as the separation media for nano-liquid chromatography (nano-LC). These columns were prepared by in-situ polymerization of 2-vinylnaphthalene (2-VNA) as the functional monomer and divinylbenzene (DVB) as the crosslinker in a fused silica capillary column of 50 µm i.d. Various porogenic solvents, including tetrahydrofuran (THF), dodecanol and toluene were used for morphology optimization. Final monolithic column (referred to as VNA column) was characterized by using scanning electron microscopy (SEM) and chromatographic analyses. Alkylbenzenes (ABs), and polyaromatic hydrocarbons (PAHs) were separated using the VNA column while the column offered excellent hydrophobic and π-π interactions under reversed-phase conditions. Theoretical plates number up to 41,200 plates/m in isocratic mode for ethylbenzene could be achieved. The potential of the final VNA column was demonstrated with a gradient elution in the separation of six intact proteins, including ribonuclease A (RNase A), cytochrome C (Cyt C), lysozyme (Lys), ß-lactoglobulin (ß-lac), myoglobin (My) and α-chymotrypsinogen (α-chym) in nano LC system. The column was then applied to the peptide analysis of trypsin digested cytochrome C, allowing a high peak capacity up to 1440 and the further proteomics analysis of COS-7 cell line was attempted applying the final monolithic column in nano-LC UV system.
Assuntos
Citocromos c , Proteômica , Cromatografia Líquida/métodos , Compostos de Vinila/químicaRESUMO
Vibrio cholerae causes cholera, an acute diarrhoeal disease. The virulence in V. cholerae is regulated by the quorum-sensing mechanism and response regulator LuxO positively regulates the expression of virulence determinants adhesion, biofilm formation, and cholera toxin production. Previous in-silico studies revealed that 2-methoxy-4-vinylphenol could bind to the ATP binding site of LuxO and the complex was compact and stable in pHs like intestinal pHs. Here, we have explored the polymeric nano-formulation of 2-methoxy-4-vinylphenol using cellulose acetate phthalate for controlled drug release and their effectiveness in attenuating the expression of V. cholerae virulence. Physico-chemical characterization of the formulation showed particles with a mean size of 91.8 ± 14 nm diameter and surface charge of - 14.7 ± 0.07 mV. The uniform round polymeric nanoparticles formed displayed about 51% burst release of the drug at pH 7 by 3rd h, followed by a controlled linear release in alkaline pH. The polymeric nanoparticles demonstrated a tenfold increase in intestinal membrane permeability ex-vivo. At lower concentrations, the 2-methoxy-4-vinylphenol polymeric nanoparticles were non-cytotoxic to Int 407 cells. In-vitro analysis at pH 6, pH 7, pH 8, and pH 9 revealed that cellulose acetate phthalate-2-methoxy-4-vinylphenol nanoparticles were non-bactericidal at concentrations up to 500 µg/mL. At 31.25 µg/mL, the nanoparticles inhibited about 50% of the biofilm formation of V. cholerae MTCC 3905 and HYR14 strains. At this concentration, the adherence of V. cholerae MTCC 3905 and HYR14 to Int 407 cell lines were also significantly affected. Gene expression analysis revealed that the expression of tcp, qrr, and ct at pH 6, 7, 8, and 9 has reduced. The CAP-2M4VP nanoparticles have demonstrated the potential to effectively reduce the virulence of V. cholerae in-vitro.
Assuntos
Cólera , Polímeros Responsivos a Estímulos , Vibrio cholerae , Humanos , Vibrio cholerae/genética , Proteínas de Bactérias/metabolismo , Compostos de Vinila/metabolismo , Regulação Bacteriana da Expressão GênicaRESUMO
Polylactic acid/butenediol vinyl alcohol copolymer (PLA/BVOH) blends with different weight ratios were prepared by melt mixing. PLA and BVOH in PLA/BVOH blends were immiscible while the weak interaction between PLA and BVOH existed. The introduction of BVOH facilitated the crystallization of PLA. Moreover, the crystallization of PLA hindered the crystallization of BVOH. Due to introduction of BVOH, PLA/BVOH blends exhibited shear thinning characteristic except that PLA/BVOH blends with 5-10 % BVOH showed similar rheological property to neat PLA. With the increase of BVOH content, the contact angle of PLA/BVOH blends decreased from 79.75° to 67.33° at 120 s. The hydrophilicity of PLA/BVOH blends was improved. In addition, PLA/BVOH fibers with 5-40 % BVOH and PLA/BVOH/rutin fibers with 3 % rutin were manufactured by melt spinning. The effect of BVOH on the mechanical property of PLA/BVOH fibers was small. However, BVOH improved significantly the rutin release rate and antioxidant properties of PLA/BVOH/rutin fibers.
Assuntos
Poliésteres , Polímeros , Polímeros/química , Poliésteres/química , Cristalização , Etanol , Compostos de VinilaRESUMO
Formulating poorly soluble molecules as amorphous solid dispersions (ASDs) is an effective strategy to improve drug release. However, drug release rate and extent tend to rapidly diminish with increasing drug loading (DL). The poor release at high DLs has been postulated to be linked to the process of amorphous-amorphous phase separation (AAPS), although the exact connection between phase separation and release properties remains somewhat unclear. Herein, release profiles of ASDs formulated with ritonavir (RTV) and polyvinylpyrrolidone/vinyl acetate (PVPVA) at different DLs were determined using surface normalized dissolution. Surface morphologies of partially dissolved ASD compacts were evaluated with confocal fluorescence microscopy, using Nile red and Alexa Fluor 488 as fluorescence markers to track the hydrophobic and hydrophilic phases respectively. ASD phase behavior during hydration and release of components were also visualized in real time using a newly developed in situ confocal fluorescence microscopy method. RTV-PVPVA ASDs showed complete and rapid drug release below 30% DL, partial drug release at 30% DL and no drug release above 30% DL. It was observed that formation of discrete drug-rich droplets at lower DLs led to rapid and congruent release of both drug and polymer, whereas formation of continuous drug-rich phase at the ASD matrix-solution interface was the cause of poor release above certain DLs. Thus, the domain size and interconnectivity of phase separated drug-rich domains appear to be critical factors impacting drug release from RTV-PVPVPA ASDs.
Assuntos
Polímeros , Pirrolidinas , Polímeros/química , Solubilidade , Pirrolidinas/química , Compostos de Vinila/química , Liberação Controlada de Fármacos , Ritonavir/química , Povidona/químicaRESUMO
The cascade sequential reaction of α-keto acids, 1-iodoalkynes, and alkyl halides are reported herein to synthesize tetra-substituted vinyl iodides. It represents an efficient protocol to access a diverse range of tetra-substituted vinyl iodides starting from simple materials in a one-pot fashion, featuring mild reaction conditions, ease of operation, and broad substrate scope.
Assuntos
Iodetos , Elementos de Transição , Cetoácidos , Catálise , Compostos de VinilaRESUMO
Inhibiting surface crystallization is an interesting strategy to enhance the physical stability of amorphous solid dispersions (ASDs), still preserving high drug loads. The aim of this study was to investigate the potential surface crystallization inhibitory effect of an additional polymer coating onto ASDs, comprising high drug loads of a fast crystallizing drug, layered onto pellets. For this purpose, bilayer coated pellets were generated with fluid-bed coating, of which the first layer constitutes a solid dispersion of naproxen (NAP) in poly(vinylpyrrolidone-co-vinyl acetate) (PVP-VA) in a 40:60 or 35:65 (w/w) ratio, and ethyl cellulose (EC) composes the second layer. The physical stability of these double-layered pellets, in comparison to pellets with an ASD layer only, was assessed under accelerated conditions by monitoring with X-ray powder diffraction (XRPD) at regular time intervals. Bilayer coated pellets were however found to be physically less stable than pellets with an ASD layer only. Applying the supplementary EC coating layer induced crystallization and heterogeneity in the 40:60 and 35:65 (w/w) NAP-PVP-VA ASDs, respectively, attributed to the initial contact with the solvent. Caution is thus required when applying an additional coating layer on top of an ASD layer with fluid-bed coating, for instance for controlled release purposes, especially if the ASD consists of high loads of a fast crystallizing drug.