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1.
Mol Pharm ; 21(6): 3017-3026, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38758116

RESUMO

Sucrose and trehalose pharmaceutical excipients are employed to stabilize protein therapeutics in a dried state. The mechanism of therapeutic protein stabilization is dependent on the sugars being present in an amorphous solid-state. Colyophilization of sugars with high glass transition polymers, polyvinylpyrrolidone (PVP), and poly(vinylpyrrolidone vinyl acetate) (PVPVA), enhances amorphous sugar stability. This study investigates the stability of colyophilized sugar-polymer systems in the frozen solution state, dried state postlyophilization, and upon exposure to elevated humidity. Binary systems of sucrose or trehalose with PVP or PVPVA were lyophilized with sugar/polymer ratios ranging from 2:8 to 8:2. Frozen sugar-PVPVA solutions exhibited a higher glass transition temperature of the maximally freeze-concentrated amorphous phase (Tg') compared to sugar-PVP solutions, despite the glass transition temperature (Tg) of PVPVA being lower than PVP. Tg values of all colyophilized systems were in a similar temperature range irrespective of polymer type. Greater hydrogen bonding between sugars and PVP and the lower hygroscopicity of PVPVA influenced polymer antiplasticization effects and the plasticization effects of residual water. Plasticization due to water sorption was investigated in a dynamic vapor sorption humidity ramping experiment. Lyophilized sucrose systems exhibited increased amorphous stability compared to trehalose upon exposure to the humidity. Recrystallization of trehalose was observed and stabilized by polymer addition. Lower concentrations of PVP inhibited trehalose recrystallization compared to PVPVA. These stabilizing effects were attributed to the increased hydrogen bonding between trehalose and PVP compared to trehalose and PVPVA. Overall, the study demonstrated how differences in polymer hygroscopicity and hydrogen bonding with sugars influence the stability of colyophilized amorphous dispersions. These insights into excipient solid-state stability are relevant to the development of stabilized biopharmaceutical solid-state formulations.


Assuntos
Estabilidade de Medicamentos , Excipientes , Liofilização , Polímeros , Povidona , Temperatura de Transição , Trealose , Liofilização/métodos , Povidona/química , Trealose/química , Excipientes/química , Polímeros/química , Sacarose/química , Açúcares/química , Ligação de Hidrogênio , Armazenamento de Medicamentos , Química Farmacêutica/métodos , Varredura Diferencial de Calorimetria , Umidade , Pirrolidinas/química , Compostos de Vinila/química
2.
Biomacromolecules ; 25(6): 3823-3830, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38773865

RESUMO

Sustainability and circularity are key issues facing the global polymer industry. The search for biodegradable and environmentally-friendly polymers that can replace conventional materials is a difficult challenge that has been met with limited success. Alternatives must be cost-effective, scalable, and provide equivalent performance. We report that latexes made by the conventional emulsion polymerization of vinyl acetate and functional vinyl ester monomers are efficient thickeners for consumer products and biodegrade in wastewater. This approach uses readily-available starting materials and polymerization is carried out in water at room temperature, in one pot, and generates negligible waste. Moreover, the knowledge that poly(vinyl ester)s are biodegradable will lead to the design of new green polymer materials.


Assuntos
Emulsões , Emulsões/química , Polimerização , Polímeros/química , Álcalis/química , Biodegradação Ambiental , Látex/química , Compostos de Vinila/química , Águas Residuárias/química
3.
J Pharm Biomed Anal ; 246: 116228, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38781726

RESUMO

Patiromer (Veltassa®) is a crosslinked, insoluble co-polymer drug used as a nonabsorbent potassium binder, approved for treatment of hyperkalemia. Quantitative solid-state 13C nuclear magnetic resonance (NMR) analysis with comprehensive peak assignment, component quantification, and calculation of mole and weight fractions of monomer units was performed on three doses of patiromer. The workflow is documented in detail. Spectrally edited solid-state 13C NMR spectra of patiromer show =CHn peaks of matching intensity at 116 and 141 ppm, characteristic of -CH=CH2 vinyl groups. Similar spectral features can be observed in earlier studies but were previously ignored. In this study, the vinyl signals are well-resolved in a 2-s direct polarization (DP) spectrum without and with dipolar dephasing, which confirms that these sp2-hybridized carbons are bonded to hydrogen and partially mobile, consistent with vinyl side groups from incompletely reacted divinyl crosslinkers. The vinyl groups account for 1.6% of all carbon, 3% of the monomer units, and nearly 1/3 of the crosslinkers. Furthermore, an unexpected OCH3 moiety accounting for ∼1.2% of all carbons was identified by spectral editing; its chemical shift of 54 ppm is more consistent with a methyl ester than with a methyl ether. It can originate from incomplete hydrolysis of ∼6% of methyl-2-fluoroacrylate, the main monomer of patiromer. Characteristic cross peaks in two-dimensional 1H-13C heteronuclear correlation NMR confirm the presence of the vinyl and OCH3 groups. Trace amounts of xanthan gum are also detected. The quantitative 13C NMR spectrum of patiromer has been matched in a simulation using a model with five monomer units.


Assuntos
Ésteres , Espectroscopia de Ressonância Magnética , Polímeros , Polímeros/química , Ésteres/química , Espectroscopia de Ressonância Magnética/métodos , Compostos de Vinila/química , Solubilidade , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13/métodos
4.
Mol Pharm ; 21(6): 2908-2921, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38743928

RESUMO

The physical stability of amorphous solid dispersions (ASDs) is a major topic in the formulation research of oral dosage forms. To minimize the effort of investigating the long-term stability using cost- and time-consuming experiments, we developed a thermodynamic and kinetic modeling framework to predict and understand the crystallization kinetics of ASDs during long-term storage below the glass transition. Since crystallization of the active phrarmaceutical ingredients (APIs) in ASDs largely depends on the amount of water absorbed by the ASDs, water-sorption kinetics and API-crystallization kinetics were considered simultaneously. The developed modeling approach allows prediction of the time evolution of viscosity, supersaturation, and crystallinity as a function of drug load, relative humidity, and temperature. It was applied and evaluated against two-year-lasting crystallization experiments of ASDs containing nifedipine and copovidone or HPMCAS measured in part I of this work. We could show that the proposed modeling approach is able to describe the interplay between water sorption and API crystallization and to predict long-term stabilities of ASDs just based on short-term measurements. Most importantly, it enables explaining and understanding the reasons for different and sometimes even unexpected crystallization behaviors of ASDs.


Assuntos
Cristalização , Água , Cristalização/métodos , Água/química , Cinética , Estabilidade de Medicamentos , Nifedipino/química , Compostos de Vinila/química , Termodinâmica , Pirrolidinas/química , Viscosidade , Química Farmacêutica/métodos , Umidade , Temperatura , Solubilidade , Metilcelulose/química , Metilcelulose/análogos & derivados
5.
Org Biomol Chem ; 22(16): 3273-3278, 2024 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-38572769

RESUMO

Arylsulfonyl group-bearing α,ß-unsaturated enol esters were readily assembled via the Cs2CO3-mediated union of 2-bromoallyl sulfones and cinnamic acids. The overall transformation is equivalent to an sp2 carbon-oxygen coupling reaction, and therefore constitutes a formal vinylic substitution. Several of the products display promising levels of antiproliferative activities higher than that of the anticancer drug carboplatin. Thiophenol reacted with 2-bromoallyl sulfones under identical conditions to afford α-thiophenyl-α'-tosyl acetone via an apparent aerial oxidation.


Assuntos
Antineoplásicos , Proliferação de Células , Ésteres , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Ésteres/química , Ésteres/farmacologia , Ésteres/síntese química , Humanos , Proliferação de Células/efeitos dos fármacos , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Estrutura Molecular , Sulfonas/química , Sulfonas/farmacologia , Sulfonas/síntese química , Relação Estrutura-Atividade , Compostos de Vinila/química , Compostos de Vinila/farmacologia , Compostos de Vinila/síntese química
6.
Dent Mater J ; 43(3): 367-374, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38583997

RESUMO

There is a growing need for a mouthguard sheet material with higher shock absorption and dispersion capacity than those obtained by conventional materials. A five-layer mouthguard sheet material was previously developed using laminated ethylene vinyl acetate and polyolefin copolymer resin. In this study, the shock absorption capacity and dispersion capability of the new sheet material were investigated and compared with those of other materials. Impact testing for the new sheet material showed that the force required to displace the sheet by 1 mm was significantly higher at all thicknesses (p<0.001), whereas the puncture energy and displacement were significantly lower than those for ethylene vinyl acetate (p<0.05). The five-layer mouthguard sheet material successfully absorbed and resisted shock. Therefore, the sheet material potentially increases resistance to applied deformation in teeth and alveolar bone and maintains structure. The five-layer sheet material could expand the range of mouthguard products and help prevent oral trauma.


Assuntos
Teste de Materiais , Protetores Bucais , Polienos/química , Compostos de Vinila/química , Desenho de Equipamento , Polivinil/química , Estresse Mecânico , Análise do Estresse Dentário
7.
Sci Rep ; 14(1): 2203, 2024 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-38272939

RESUMO

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/química
8.
Mol Pharm ; 21(2): 770-780, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38181202

RESUMO

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/métodos
9.
Mol Pharm ; 20(4): 2217-2234, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36926898

RESUMO

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/métodos
10.
J Chromatogr A ; 1690: 463804, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36689803

RESUMO

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/química
11.
Int J Pharm ; 630: 122455, 2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36460129

RESUMO

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.


Assuntos
Polímeros , Compostos de Vinila , Polímeros/química , Solubilidade , Compostos de Vinila/química , Pirrolidinas/química , Implantes de Medicamento
12.
J Pharm Sci ; 112(1): 304-317, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36306863

RESUMO

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/química
13.
Adv Food Nutr Res ; 100: 109-129, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35659350

RESUMO

The health and safety concerns associated with synthetic antioxidants has resulted in an urgent search for natural sources of antioxidants. Such antioxidants are not only convenient but may also have important therapeutic properties. Oilseed crops, for example, are rich in phenolic compounds some of which exhibit powerful antioxidant properties that have broad applications in both the food and feed industry. Often, the concentration of these phenolic compounds is affected by many processing conditions including temperature, pressure, pH, and extracting solvents. Hence it is important to optimize processing conditions to obtain maximum levels of those antioxidants with superior antioxidant activity. Oilseeds, such as canola and mustard, are rich sources of sinapates and kaempferol derivatives. When subjected to different processing conditions, including pressurized temperature, sinapates are converted to vinyl phenol derivatives, of which the major one is canolol. This chapter will focus on the nature of canolol and its applications in food and medicine.


Assuntos
Antioxidantes , Fenóis , Antioxidantes/farmacologia , Fenóis/química , Fenóis/farmacologia , Compostos de Vinila/química
14.
J Am Chem Soc ; 144(28): 12979-12988, 2022 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-35763561

RESUMO

Many common polymers, especially vinyl polymers, are inherently difficult to chemically recycle and are environmentally persistent. The introduction of low levels of cleavable comonomer additives into existing vinyl polymerization processes could facilitate the production of chemically deconstructable and recyclable variants with otherwise equivalent properties. Here, we report thionolactones that serve as cleavable comonomer additives for the chemical deconstruction and recycling of vinyl polymers prepared through free radical polymerization, using polystyrene (PS) as a model example. Deconstructable PS of different molar masses (∼20-300 kDa) bearing varied amounts of statistically incorporated thioester backbone linkages (2.5-55 mol %) can be selectively depolymerized to yield well-defined thiol-terminated fragments (<10 kDa) that are suitable for oxidative repolymerization to generate recycled PS of nearly identical molar mass to the parent material, in good yields (80-95%). A theoretical model is provided to generalize this molar mass memory effect. Notably, the thermomechanical properties of deconstructable PS bearing 2.5 mol % of cleavable linkages and its recycled product are similar to those of virgin PS. The additives were also shown to be effective for deconstruction of a cross-linked styrenic copolymer and deconstruction and repolymerization of a polyacrylate, suggesting that cleavable comonomers may offer a general approach toward circularity of many vinyl (co)polymers.


Assuntos
Poliestirenos , Compostos de Vinila , Peso Molecular , Polimerização , Polímeros/química , Compostos de Vinila/química
15.
ACS Macro Lett ; 11(5): 706-710, 2022 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-35570803

RESUMO

Conventionally inaccessible end-functionalized vinyl polymers were synthesized via orthogonal side-chain replacement for terminal and repeating units of poly(alkenyl boronate)s. A terminal-defined polymer of isopropenyl boronic acid pinacol ester (IPBpin) was synthesized via RAFT polymerization, and subsequent cobalt (Co)-catalyzed end olefination afforded the polymer carrying the C(sp2)-B bond at the terminal and the C(sp3)-B bond in repeating units. Herein, the terminal C(sp2)-B bond was selectively transformable via palladium (Pd)-catalyzed Suzuki-Miyaura cross coupling, and subsequent transformation of the repeating C(sp3)-B unit gave the poly(α-methyl vinyl alcohol) [poly(MVA)] bearing various functional groups at the terminal. The boron-based stepwise polymer reaction thus overcame the synthetic difficulty of the end-functionalized poly(MVA), which is ascribed to the poor polymerization ability of the corresponding acetate monomer, i.e., isopropenyl acetate.


Assuntos
Ácidos Borônicos , Polímeros , Ácidos Borônicos/química , Paládio/química , Polimerização , Polímeros/química , Compostos de Vinila/química
16.
Curr Protoc ; 2(3): e386, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35316581

RESUMO

Crosslinking reactions to nucleic acids are an effective way to prepare stable complexes formed by covalent bonding. We demonstrated that fully 2'-O-methylated (2'-OMe) RNAs having a 2-amino-6-vinylpurine (AVP) exhibited an efficient crosslinking to uracil in the target RNA. Recently, we reported the preparation of crosslinked 2'-OMe RNA duplexes using AVP and the anti-miRNA oligonucleotides (AMOs) containing crosslinked duplexes at the terminal positions. These AMOs exhibited efficient microRNA (miRNA) inhibition at very low concentrations. In this article, we describe the chemical synthesis of 2'-OMe oligonucleotides containing AVP and preparation of the AMOs bearing crosslinked 2'-OMe RNA duplexes using AVP. In addition, we describe in detail the miRNA inhibition assay using these AMOs. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Synthesis of phosphoramidite of 2-amino-6-vinylguanosine derivative Basic Protocol 2: Synthesis of AVP-2'-OMe RNA Basic Protocol 3: Evaluation of the crosslink reactivity of CFO containing AVP to the 2'-OMe RNA and preparation of AMOs containing crosslinked duplex Basic Protocol 4: miRNA inhibition assays.


Assuntos
MicroRNAs , Oligonucleotídeos/química , Purinas/química , Compostos de Vinila/química
17.
Pharm Res ; 39(2): 381-397, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35169959

RESUMO

PURPOSE: To understand the role of different surfactants, incorporated into amorphous solid dispersions (ASDs) of ritonavir and copovidone, in terms of their impact on release, phase behavior and stabilization of amorphous precipitates formed following drug release. METHODS: Ternary ASDs with ritonavir, copovidone and surfactants (30:70:5 w/w/w) were prepared by rotary evaporation. ASD release performance was tested using Wood's intrinsic dissolution rate apparatus and compared to the binary drug-polymer ASD with 30% drug loading. Size measurement of amorphous droplets was performed using dynamic light scattering. Solid state characterization was performed using attenuated total reflectance-infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy. RESULTS: All surfactant-containing ASDs showed improvement over the binary ASD. Span 85 and D-α-tocopheryl polyethylene glycol succinate (TPGS) showed complete release with no evidence of AAPS or crystallization whereas Span 20 and Tween 80 showed < 50% release with amorphous amorphous phase separation (AAPS). Span 20 also induced solution crystallization. Sodium dodecyl sulfate (SDS) showed very rapid, albeit incomplete (~ 80%) release. AAPS was not observed with SDS. However, crystallization on the dissolving solid surface was noted. Span 20 and TPGS formed the smallest and most size-stable droplets with ~ 1 µm size whereas coalescence was noted with other surfactants. CONCLUSIONS: Surfactants improved the release performance relative to the binary ASD. Different surfactant types impacted overall performance to varying extents and affected different attributes. Overall, Span 85 showed best performance (complete release, no crystallization/AAPS and small droplet size). Correlation between physicochemical properties and surfactant performance was not observed.


Assuntos
Inibidores da Protease de HIV/química , Hexoses/química , Pirrolidinas/química , Ritonavir/química , Tensoativos/química , Compostos de Vinila/química , Composição de Medicamentos , Liberação Controlada de Fármacos , Cinética , Polissorbatos/química , Solubilidade , Vitamina E/química
18.
Artigo em Inglês | MEDLINE | ID: mdl-34634490

RESUMO

Glycerophospholipids are major components of cell membranes and have enormous variation in the composition of fatty acyl chains esterified on the sn-1 and sn-2 position as well as the polar head groups on the sn-3 position of the glycerol backbone. Phospholipase A2 (PLA2) enzymes constitute a superfamily of enzymes which play a critical role in metabolism and signal transduction by hydrolyzing the sn-2 acyl chains of glycerophospholipids. In human cell membranes, in addition to the conventional diester phospholipids, a significant amount is the sn-1 ether-linked phospholipids which play a critical role in numerous biological activities. However, precisely how PLA2s distinguish the sn-1 acyl chain linkage is not understood. In the present study, we expanded the technique of lipidomics to determine the unique in vitro specificity of three major human PLA2s, including Group IVA cytosolic cPLA2, Group VIA calcium-independent iPLA2, and Group V secreted sPLA2 toward the linkage at the sn-1 position. Interestingly, cPLA2 prefers sn-1 vinyl ether phospholipids known as plasmalogens over conventional ester phospholipids and the sn-1 alkyl ether phospholipids. iPLA2 showed similar activity toward vinyl ether and ester phospholipids at the sn-1 position. Surprisingly, sPLA2 preferred ester phospholipids over alkyl and vinyl ether phospholipids. By taking advantage of molecular dynamics simulations, we found that Trp30 in the sPLA2 active site dominates its specificity for diester phospholipids.


Assuntos
Fosfolipases A2/genética , Éteres Fosfolipídicos/metabolismo , Fosfolipídeos/genética , Compostos de Vinila/metabolismo , Cálcio/metabolismo , Membrana Celular/genética , Membrana Celular/metabolismo , Citosol/metabolismo , Glicerofosfolipídeos/química , Glicerofosfolipídeos/metabolismo , Humanos , Hidrólise , Cinética , Fosfolipases A2/metabolismo , Fosfolipídeos/metabolismo , Especificidade por Substrato/genética , Compostos de Vinila/química
19.
Mol Pharm ; 19(1): 303-317, 2022 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-34932358

RESUMO

A molecular descriptor known as R3m (the R-GETAWAY third-order autocorrelation index weighted by the atomic mass) was previously identified as capable of grouping members of an 18-compound library of organic molecules that successfully formed amorphous solid dispersions (ASDs) when co-solidified with the co-polymer polyvinylpyrrolidone vinyl acetate (PVPva) at two concentrations using two preparation methods. To clarify the physical meaning of this descriptor, the R3m calculation is examined in the context of the physicochemical mechanisms of dispersion formation. The R3m equation explicitly captures information about molecular topology, atomic leverage, and molecular geometry, features which might be expected to affect the formation of stabilizing non-covalent interactions with a carrier polymer, as well as the molecular mobility of the active pharmaceutical ingredient (API) molecule. Molecules with larger R3m values tend to have more atoms, especially the heavier ones that form stronger non-covalent interactions, generally, more irregular shapes, and more complicated topology. Accordingly, these molecules are more likely to remain dispersed within PVPva. Furthermore, multiple linear regression modeling of R3m and more interpretable descriptors supported these conclusions. Finally, the utility of the R3m descriptor for predicting the formation of ASDs in PVPva was tested by analyzing the commercially available products that contain amorphous APIs dispersed in the same polymer. All of these analyses support the conclusion that the information about the API geometry, size, shape, and topological connectivity captured by R3m relates to the ability of a molecule to interact with and remain dispersed within an amorphous PVPva matrix.


Assuntos
Composição de Medicamentos/métodos , Liberação Controlada de Fármacos , Povidona/química , Compostos de Vinila/química , Modelos Químicos , Estrutura Molecular
20.
Nat Commun ; 12(1): 5956, 2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34642311

RESUMO

Photoredox catalysis is a powerful means to generate odd-electron species under mild reaction conditions from a wide array of radical precursors. Herein, we present the application of this powerful catalytic manifold to address the hydroalkylation and hydroaminoalkylation of electronically diverse vinylarenes. This reaction allows for generalized alkene hydroalkylation leveraging common alkyl radical precursors, such as organotrifluoroborate salts and carboxylic acids. Furthermore, utilizing easily accessible α-silyl amine reagents or tertiary amines directly, secondary and tertiary amine moieties can be installed onto monoaryl and diaryl alkenes to access valuable products, including γ,γ-diarylamines pharmacophores. Thus, under a unified system, both hydroalkylation and hydroaminoalkylation of alkenes are achieved. The substrate scope is evaluated through 57 examples, the synthetic utility of the method is demonstrated, and preliminary mechanistic insights are presented.


Assuntos
Aminas/síntese química , Compostos de Boro/química , Ácidos Carboxílicos/química , Elétrons , Compostos Macrocíclicos/síntese química , Compostos de Vinila/química , Alquilação , Catálise , Técnicas de Química Sintética/métodos , Humanos , Oxirredução , Processos Fotoquímicos
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