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1.
Int J Pharm ; 647: 123516, 2023 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-37863447

RESUMO

Thiabendazole is an anthelmintic drug used to treat strongyloidiasis (threadworm), cutaneous and visceral larva migrans, trichinosis, and other parasites. The active pharmaceutical ingredient is typically administered orally as tablets that should be chewed before swallowing. Current formulations combine the active ingredient with excipients, including sodium saccharinate as a sweetener. Thiabendazole's low aqueous solubility hinders fast dissolution and absorption through the mucous membranes. We sought to reformulate this medicine to improve both solubility and palatability. We utilized the possibility of protonation of the azole nitrogen atom and selected four different hydrogen donors: saccharin, fumaric, maleic, and oxalic acids. Solvothermal synthesis resulted in salts with each co-former, whereas neat and liquid-assisted grinding enabled the synthesis of additional formulations. Product formation was observed by powder X-ray diffraction. To better understand the structural basis of the proton transfer, we solved the crystal structures of the salts with saccharin, maleic acid, and oxalic acid using single-crystal X-ray diffraction. The structure of the salt with fumaric acid was solved by powder X-ray diffraction. We further characterized the salts with vibrational spectroscopic and thermoanalytical methods. We report a broad tunability of the aqueous solubility of thiabendazole by salt formation. Reformulation with maleic acid provided a 60-fold increase in solubility, while saccharin and oxalic acid gave a modest improvement. Fumaric acid resulted in a solid with only slightly higher solubility. Furthermore, saccharin is a sweetener, while the acids taste sour. Therefore, the salts formed also result in an intrinsic improvement of palatability. These results can inform new strategies for oral and chewable tablet formulations for treating helminthic infections.


Assuntos
Anti-Helmínticos , Anti-Infecciosos , Sais/química , Sacarina/química , Pós , Tiabendazol , Difração de Raios X , Solubilidade , Edulcorantes , Comprimidos , Ácido Oxálico
2.
ChemMedChem ; 18(22): e202300454, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37837260

RESUMO

This study explores the binding mechanisms of saccharin derivatives with human carbonic anhydrase IX (hCA IX), an antitumor drug target, with the aim of facilitating the design of potent and selective inhibitors. Through the use of crystallographic analysis, we investigate the structures of hCA IX-saccharin derivative complexes, unveiling their unique binding modes that exhibit both similarities to sulfonamides and distinct orientations of the ligand tail. Our comprehensive structural insights provide information regarding the crucial interactions between the ligands and the protein, shedding light on interactions that dictate inhibitor binding and selectivity. Through a comparative analysis of the binding modes observed in hCA II and hCA IX, isoform-specific interactions are identified, offering promising strategies for the development of isoform-selective inhibitors that specifically target tumor-associated hCA IX. The findings of this study significantly deepen our understanding of the binding mechanisms of hCA inhibitors, laying a solid foundation for the rational design of more effective inhibitors.


Assuntos
Anidrases Carbônicas , Neoplasias , Humanos , Anidrase Carbônica IX/metabolismo , Sacarina/farmacologia , Sacarina/química , Anidrases Carbônicas/metabolismo , Antígenos de Neoplasias/metabolismo , Isoformas de Proteínas/metabolismo , Inibidores da Anidrase Carbônica/química , Relação Estrutura-Atividade , Estrutura Molecular
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 290: 122269, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-36566534

RESUMO

The use of saccharin in food products attracts much attention as it involves the risk of lethal allergies and many protein aggregation diseases. However, its role in protein aggregation has not been explored to date. This study embodies the effect of artificial sweeteners on HEWL in the absence and presence of commonly available natural products such as curcumin and EGCG. Various techniques have been used to characterize the protein interaction, such as steady-state emission and time-resolved fluorescence, FTIR, gel electrophoresis, TEM, and molecular docking. Steady-state and time-resolved studies revealed the binding strength and concomitant effect of saccharin on HEWL protein. Kinetic measurements revealed that saccharin causes significant enhancement of HEWL aggregation with a considerable reduction in lag phase time i.e. from 37 hr to 08 hr. Whereas in the presence of natural products, the effect of saccharin on HEWL aggregation was significantly reduced specifically in the case of curcumin. The result obtained in the fluorescence experiment were also supported by the gel electrophoresis technique and morphological images taken by TEM. The rapid change in the secondary structure of the protein in the presence of saccharin was confirmed by the FTIR spectroscopy technique. This study is instrumental in understanding the effect of saccharin on protein aggregation and the role of commonly available natural products in curbing its effect.


Assuntos
Curcumina , Sacarina , Sacarina/farmacologia , Sacarina/química , Edulcorantes/farmacologia , Muramidase/química , Simulação de Acoplamento Molecular , Agregados Proteicos , Curcumina/farmacologia , Proteínas , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Angew Chem Int Ed Engl ; 61(41): e202206293, 2022 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-35894150

RESUMO

We present SpeedMixing, a rapid blending technology, as an approach for fast mechanosynthesis and discovery of model pharmaceutical cocrystals through rapid spinning in the absence of bulk solvents and milling/grinding media. Syntheses of pharmaceutical cocrystals based on the active pharmaceutical ingredients (APIs) carbamazepine, dihydrocarbamazepine, and nicotinamide demonstrate SpeedMixing as a method for rapid, scalable, as well as controllable and selective synthesis of cocrystals, cocrystal polymorphs and stoichiomorphs, including the discovery of an unexpected methanol solvate of the archetypal cocrystal of carbamazepine and saccharin, which has eluded extensive screens over 20 years.


Assuntos
Metanol , Sacarina , Carbamazepina/química , Cristalização/métodos , Niacinamida/química , Preparações Farmacêuticas , Sacarina/química , Solventes/química
5.
J Pharm Sci ; 111(1): 88-94, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34139260

RESUMO

The purpose of this study is to investigate the effects of dry and wet mechanochemical synthesis on piroxicam (PX) and saccharin (SA) mixtures. For this purpose, PX and SA mixtures prepared by wet mechanochemical processes using three solvents and by dry mechanochemical synthesis were evaluated by mid-and near-infrared spectroscopy, powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC). The mixtures of wet-type products were transformed into PX/SA 1:1 co-crystals. The effect of the solvent was key to the co-crystallization of PX and SA. The products from the dry process were transformed into the amorphous phase. For the sample of the amorphous mixture, two exothermic peaks due to crystallization were observed in the thermal analysis. Bulk PX was ground for the same number of times for transformation, but was not successfully transformed to the amorphous bulk; the same was observed for SA. It is suggested that the mutual existence of PX and SA promotes mutual amorphization.


Assuntos
Piroxicam , Sacarina , Varredura Diferencial de Calorimetria , Piroxicam/química , Difração de Pó , Pós , Sacarina/química , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Espectroscopia de Luz Próxima ao Infravermelho , Difração de Raios X
6.
Pharm Res ; 38(10): 1777-1791, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34729701

RESUMO

PURPOSE: This study aimed to improve the in vitro dissolution, permeability and oral bioavailability of adefovir dipivoxil (ADD) by cocrystal technology and clarify the important role of coformer selection on the cocrystal's properties. METHODS: ADD was cocrystallized with three small molecules (i.e., paracetamol (PA), saccharin (SAC) and nicotinamide (NIC)), respectively. The obtained ADD-PA cocrystal was characterized by DSC, TGA, PXRD and FTIR. Comparative study on dissolution rates among the three ADD cocrystals were conducted in water and pH 6.8 phosphate buffer. Besides, effects of coformers on intestinal permeability of ADD were evaluated via in vitro Caco-2 cell model and in situ single-pass intestinal perfusion model in rats. Furthermore, in vivo pharmacokinetic study of ADD cocrystals was also compared. RESULTS: Dissolution rates of ADD cocrystals were improved with the order of ADD-SAC cocrystal > ADD-PA cocrystal > ADD-NIC cocrystal. The permeability studies on Caco-2 cell model and single-pass intestinal perfusion model indicated that PA could enhance intestinal absorption of ADD by P-gp inhibition, while SAC and NIC did not. Further in vivo pharmacokinetic study showed that ADD-SAC cocrystal exhibited higher Cmax (1.4-fold) and AUC0-t (1.3-fold) of ADD than administration of ADD alone, and Cmax and AUC0-t of ADD-PA cocrystal were significantly enhanced by 2.1-fold and 2.2-fold, respectively, which was attributed to its higher dissolution and improved intestinal permeability. CONCLUSION: Coformer selection had an important role on cocrystal's properties, and cocrystallization of ADD with a suitable coformer was an effective approach to enhance both dissolution and bioavailability of ADD.


Assuntos
Adenina/análogos & derivados , Organofosfonatos/química , Organofosfonatos/farmacocinética , Acetaminofen/química , Adenina/química , Adenina/farmacocinética , Animais , Área Sob a Curva , Células CACO-2 , Permeabilidade da Membrana Celular , Química Farmacêutica , Cristalização , Humanos , Concentração de Íons de Hidrogênio , Absorção Intestinal , Modelos Biológicos , Conformação Molecular , Niacinamida/química , Ratos , Sacarina/química , Solubilidade , Água
7.
Mol Pharm ; 18(11): 4111-4121, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34641686

RESUMO

The effects of pH changes and saccharin (SAC) addition on the nanostructure and mobility of the cationic aminoalkyl methacrylate copolymer Eudragit E PO (EUD-E) and its drug solubilization ability were investigated. Small-angle X-ray scattering performed using synchrotron radiation and atomic force microscopy showed that the EUD-E nanostructure, which has a size of approximately several nanometers, changed from a random coil structure at low pH (pH 4.0-5.0) to a partially folded structure at high pH (pH 5.5-6.5). The EUD-E also formed a partially folded structure in a wide pH range of 4.5-6.5 when SAC was present, and the coil-to-globule transition was moderate with pH increase, compared with that when SAC was absent. The equilibrium solubility of the neutral drug naringenin (NAR) was enhanced in the EUD-E solution and further increased as the pH increased. The enlargement of the hydrophobic region of EUD-E in association with the coil-to-globule transition led to efficient solubilization of NAR. The interaction with SAC enhanced the mobility of the EUD-E chains in the hydrophobic region of EUD-E, resulting in changes in the drug-solubilizing ability. 1H high-resolution magic-angle spinning NMR measurements revealed that the solubilized NAR in the partially folded structure of EUD-E showed higher molecular mobility in the presence of SAC than in the absence of SAC. This study highlighted that solution pH and the presence of SAC significantly changed the drug solubilization ability of EUD-E, followed by changes in the EUD-E nanostructure, including its hydrophobic region.


Assuntos
Flavanonas/química , Nanoestruturas/química , Ácidos Polimetacrílicos/química , Química Farmacêutica , Excipientes/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Espectroscopia de Prótons por Ressonância Magnética , Sacarina/química , Espalhamento a Baixo Ângulo , Solubilidade , Difração de Raios X
8.
Int J Biol Macromol ; 183: 1136-1144, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-33932423

RESUMO

The probiotics are extremely sensitive to various environmental factors, which imposes limitation on their health and functional effectiveness. Thus, development of delivery system for protection of viable cells while passing through different stages of the human digestion system is key factor in application of probiotic products. In our study, the effects of several polysaccharides such as alginate, κ-carrageenan, locust bean gum, gellan gum, xanthan gum and their combination with various prebiotic components (resistant starch, lactulose, lactosucrose) on encapsulation of probiotic Lactobacillus casei 01 strain were studied. Both regular and unregular beads with size distributions from 2 mm up to 5 mm were obtained. The encapsulation efficiencies varied from 64.4% up to 79%. Based on the texture's profiles, the capsules can be grouped into 5 clusters with squared Euclidean distance 3.5. Meanwhile, the starch-alginate and the lactosucrose LS55L - alginate beads were found to be the most stable and to have massive textural properties, whereas the gellan gum - xanthan gum and the chitosan coated alginate beads emerged as the softest. Encapsulation significantly improved the degree of gastric tolerance of probiotic cells even in the presence of pepsin. The INFOGEST in vitro digestion protocol was adapted to investigate the protection effects of different capsules. The highest survival (with loss rate of lower than 1 log CFU/g) was observed in the case of the cells encapsulated in starch-alginate beads. Moreover, the alginate microcapsules combined with lactosucrose LS55L also provided very promising shield for probiotics from the low pH of gastric conditions. Our findings suggest that incorporation of prebiotics into alginate-base encapsulation would be good idea in development of micro delivery systems that helps the survival of probiotics and their delivery to the target sites of action in human body.


Assuntos
Lacticaseibacillus casei/fisiologia , Polissacarídeos/química , Probióticos/química , Composição de Medicamentos , Estabilidade de Medicamentos , Humanos , Concentração de Íons de Hidrogênio , Lactulose/química , Tamanho da Partícula , Prebióticos , Amido Resistente , Sacarina/química , Trissacarídeos/química
9.
Dalton Trans ; 50(23): 8196-8217, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34031678

RESUMO

Herein, we designed six kinetically labile ruthenium(ii) complexes containing saccharin (sac) and 4'-substituted-2,2':6',2''-terpyridines (R-tpy), viz. trans-[Ru(sac)2(H2O)3(dmso-S)] (1) and [RuII(R-tpy)(sac)2(X)] [X = solvent molecule] (2-6). We intentionally kept the labile hydrolysable Ru-X bonds that were potentially activated via solvent-exchange reactions. This strategy generates a coordinative vacancy that allows further binding with potential biological targets. To gain insight into the electronic effects of ancillary ligands on Ru-X ligand-exchange kinetics or photoreactions, we have used a series of substituted terpyridines (R-tpy) and studied their solvation kinetics. The ternary complexes were also studied for their potential utility in Ru-assisted photoactivated chemotherapy (PACT) synergized with release of saccharin as a highly selective carbonic anhydrase IX (CA-IX) inhibitor, over-expressed in hypoxic tumors. The ternary complexes exhibit distorted octahedral geometry around Ru(ii) from two monodentate transoidal saccharin in the axial position, and tridentate terpyridines and labile solvent molecules at the basal plane (2-6). We studied their speciation, solvation kinetics, and photoreactivity in the presence of green LED light (λirr = 530 nm). All the complexes are relatively labile and undergo solvation in coordinating solvents (e.g. DMSO/DMF). The complexes undergo the ligand-substitution reaction, and their speciation and kinetics were studied by UV-Vis, ESI-MS, 1H-NMR, and structural analysis. We also attempted to assess the effect of various substituents on the ancillary terpyridine ligand (R-tpy) in photo-reactivity and ligand-exchange reactions. The photo-induced absorption and emission measurements suggested dissociation of the saccharin from the Ru-center supporting PACT pathways. The complexes display a significant binding affinity with CT-DNA (Kb ∼ 104-105 M-1) and bovine serum albumin (BSA) (KBSA ∼ 105 M-1). Cytotoxicity was studied in the dark and the presence of low energy UV-A light (365 nm) in cervical cancer cells (HeLa) and breast cancer cells (MCF7). Photoirradiation of the complexes induces the generation of reactive oxygen species (ROS) assessed using 1,3-diphenylisobenzofuran (DPBF) and intracellular DCFDA assays. The complexes are sufficiently internalized in cancer cells throughout the cytoplasm and nucleus and induce apoptosis as studied by staining with dual dyes using confocal microscopy.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Fotoquimioterapia , Piridinas/farmacologia , Rutênio/farmacologia , Sacarina/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Bovinos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , DNA/química , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Cinética , Estrutura Molecular , Processos Fotoquímicos , Piridinas/química , Rutênio/química , Sacarina/química , Células Tumorais Cultivadas
10.
Molecules ; 26(4)2021 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-33671544

RESUMO

Phospha-Michael addition, which is the addition reaction of a phosphorus-based nucleophile to an acceptor-substituted unsaturated bond, certainly represents one of the most versatile and powerful tools for the formation of P-C bonds, since many different electrophiles and P nucleophiles can be combined with each other. This offers the possibility to access many diversely functionalized products. In this work, two kinds of basic pyridine-based organo-catalysts were used to efficiently catalyze phospha-Michael addition reactions, the 4-N,N-dimethylaminopyridinium saccharinate (DMAP·Hsac) salt and a fluorous long-chained pyridine (4-Rf-CH2OCH2-py, where Rf = C11F23). These catalysts have been synthesized and characterized by Lu's group. The phospha-Michael addition of diisopropyl, dimethyl or triethyl phosphites to α, ß-unsaturated malonates in the presence of those catalysts showed very good reactivity with high yield at 80-100 °C in 1-4.5 h with high catalytic recovery and reusability. With regard to significant catalytic recovery, sometimes more than eight cycles were observed for DMAP·Hsac adduct by using non-polar solvents (e.g., ether) to precipitate out the catalyst. In the case of the fluorous long-chained pyridine, the thermomorphic method was used to efficiently recover the catalyst for eight cycles in all the reactions. Thus, the easy separation of the catalysts from the products revealed the outstanding efficacy of our systems. To our knowledge, these are good examples of the application of recoverable organo-catalysts to the DMAP·Hsac adduct by using non-polar solvent and a fluorous long-chained pyridine under the thermomorphic mode in phospha-Michael addition reactions.


Assuntos
Malonatos/química , Metilaminas/química , Organofosfonatos/química , Compostos Organofosforados/síntese química , Fosfitos/química , Piridinas/química , Sacarina/química , Catálise , Estrutura Molecular , Compostos Organofosforados/química , Sais/química
11.
Molecules ; 26(4)2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33673320

RESUMO

Local anesthetics are widely utilized in dentistry, cosmetology, and medicine. Local anesthesia is essential to providing a pain-free experience during dental and local surgeries as well as cosmetic procedures. However, the injection itself may produce discomfort and be a source of aversion. A novel approach toward the taste modulation of local anesthetics is proposed, in which the anesthetics of the "-caine" family serve as cations and are coupled with anionic sweeteners such as saccharinate and acesulfamate. Ionic conjugates of vasoconstrictor epinephrine such as epinephrine saccharinate and epinephrine acesulfamate have also been synthesized. Novel ionic conjugates were developed using anion exchange techniques. Reported compounds are sweet-tasting and are safe to use both topically and as injections.


Assuntos
Anestésicos Locais/química , Odontologia , Epinefrina/química , Vasoconstritores/química , Anestésicos Locais/farmacologia , Animais , Epinefrina/farmacologia , Humanos , Injeções , Íons/química , Lidocaína/química , Lidocaína/farmacologia , Ratos , Sacarina/química , Sacarina/farmacologia , Paladar , Vasoconstritores/farmacologia
12.
Int J Pharm ; 588: 119716, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32758593

RESUMO

Amorphous and co-amorphous formulations have been used to enhance the solubility and bioavailability of poorly water-soluble drugs. However, during handling and/or storage amorphous solids present inherent instability and overtime recrystallize back into their crystalline counterpart. The development of tools capable of quantifying and monitoring the recrystallization of amorphous materials is required to ensure the delivery of solid dosage forms with improved performance. This work describes the development and validation of a computational model for simple measurement of amorphous and co-amorphous olanzapine (OLZ) fractions in tablets. Amorphous OLZ produced by quench cooling and co-amorphous OLZ by solvent evaporation using saccharin (SAC) as a co-former were characterized by calorimetry (DSC), diffractometry (XRPD) and spectroscopy (FTIR and NIR). Spectral differences were used to predict the fraction of amorphous OLZ in samples containing different fractions of powdered amorphous and co-amorphous OLZ:SAC. The models were shown to be linear, accurate and reproducible. Blends of (co)amorphous OLZ and excipients were directly compacted at different pressures and dwell times to impose physical stress on the systems. Data collected from the analysis of the tablets was used in the model to monitor the stability of amorphous and co-amorphous OLZ demonstrating the applicability and validity of the model.


Assuntos
Excipientes/química , Modelos Químicos , Olanzapina/química , Sacarina/química , Simulação por Computador , Cristalização , Composição de Medicamentos , Estabilidade de Medicamentos , Reprodutibilidade dos Testes , Solubilidade , Comprimidos , Fatores de Tempo
13.
Eur J Med Chem ; 202: 112535, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32653697

RESUMO

New mononuclear complexes [Mn(NO3)(sac)(H2O)(bzimpy)]·2DMF (Mn), [Fe(sac)2(H2O)(bzimpy)]·2H2O (Fe), [Co(bzimpy)2](sac)2·2H2O (Co), [Ni(bzimpy)2](sac)2·H2O·i-PrOH (Ni) and [Cu(sac)2(bzimpy)]·3DMF (Cu) (sac = saccharinate and bzimpy = 2,6-bis(2-benzimidazolyl)pyridine) were synthesized and structurally characterized by elemental analysis, UV-Vis, IR, ESI-MS and X-ray diffraction. The anticancer activity of the metal complexes against A549 (lung), MCF-7 (breast), HT29 (colon) cancer cells and MCF10A (normal human breast epithelial) cells was tested and compared with those of cisplatin and bzimpy. The complexes displayed potent cytotoxic activity especially in MCF-7 and A549 cell lines, but they were practically inactive against the normal cells. Mechanistic studies with Mn and Cu complexes on A549 cells indicated that the complexes induced G0/G1 arrest. Both complexes increased intracellular ROS (reactive oxygen species) levels and successfully caused both mitochondrial dysfunction and double-strand DNA breaks. The up-regulated Bax and down-regulated Bcl-2 expression levels, caspase-3/7 activation and reduced Fas expression indicated that Mn and Cu induced ROS-dependent mitochondria-mediated intrinsic apoptosis in A549 cells.


Assuntos
Antineoplásicos/farmacologia , Benzimidazóis/farmacologia , Complexos de Coordenação/farmacologia , Metais Pesados/farmacologia , Piridinas/farmacologia , Sacarina/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Benzimidazóis/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Metais Pesados/química , Estrutura Molecular , Piridinas/química , Sacarina/análogos & derivados , Sacarina/química , Relação Estrutura-Atividade , Células Tumorais Cultivadas
14.
Chem Commun (Camb) ; 56(66): 9461-9464, 2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32677641

RESUMO

The enantioselective 1,4-alkynylation of conjugated imines derived from saccharin with aryl- and alkyl-substituted terminal alkynes has been achieved. The reaction mediated by diethylzinc in the presence of a catalytic amount of a bis(hydroxy)malonamide chiral ligand provides the corresponding imines bearing a propargylic stereocenter with moderate yields and fair to excellent enantioselectivities.


Assuntos
Iminas/química , Sacarina/química , Zinco/química , Catálise , Cristalografia por Raios X , Iminas/síntese química , Ligantes , Conformação Molecular , Estereoisomerismo
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 236: 118346, 2020 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-32302958

RESUMO

Carbamazepine cocrystals with nicotinamide, saccharin and fumaric acid were synthesized and characterized by time-domain terahertz spectroscopy. Lattice vibrations of cocrystals with their individual constituents were investigated by means of the dispersion-corrected density functional theory with and without cell parameter constraints. The simulated THz spectra successfully reproduce the features of all the crystals in their experimental spectra. A better agreement between experimental and theoretical THz spectra is achieved when the cell parameter constraints are applied in geometry optimization. Some intensive modes of neat carbamazepine and cocrystals were discussed in terms of the motions of hydrogen bonds. The effect of lattice vibration on these cocrystallizations was further examined to gain insights into the thermodynamics. It is found that lattice vibration is favorable for all these cocrystal formations.


Assuntos
Carbamazepina/química , Fumaratos/química , Niacinamida/química , Sacarina/química , Espectroscopia Terahertz/métodos , Cristalização/métodos , Teoria da Densidade Funcional , Ligação de Hidrogênio , Pós , Termodinâmica , Vibração , Difração de Raios X
16.
Int J Pharm ; 577: 119089, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32001292

RESUMO

Ligustrazine (or Tetramethylpyrazine, TMP) is an active pharmaceutical ingredient that faces the challenges of bitter taste and low oral bioavailability by the commercial phosphate salt (TMP-Pho). We tackled these challenges by forming salts with two sweeteners, acesulfame (Acs) and saccharine (Sac). Both salts effectively masked the bitter taste of TMP. Compared to TMP-Pho, TMP-Sac shows 43% lower solubility and 11% lower permeability while TMP-Acs shows higher (two-fold) solubility but 24% lower permeability. Both TMP-Acs and TMP-Sac exhibited approximately 40% higher bioavailability through reducing the rate of TMP absorption. Thus, salt formation with both sweeteners simultaneously addressed the challenges brought about by the bitter taste and lower bioavailability of TMP.


Assuntos
Pirazinas/administração & dosagem , Edulcorantes/química , Paladar , Administração Oral , Adulto , Animais , Disponibilidade Biológica , Método Duplo-Cego , Feminino , Humanos , Masculino , Permeabilidade , Pirazinas/química , Pirazinas/farmacocinética , Ratos , Ratos Sprague-Dawley , Sacarina/química , Solubilidade , Tiazinas/química , Adulto Jovem
17.
J Med Chem ; 63(5): 2470-2488, 2020 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-31972093

RESUMO

Two series of saccharin/isoxazole and saccharin/isoxazoline hybrids were synthesized by 1,3-dipolar cycloaddition. The new compounds showed to be endowed with potent and selective inhibitory activity against the cancer-related human carbonic anhydrase (hCA) IX and XII isoforms in the nanomolar range, while no affinity was encountered for off-targets, such as hCA I and II. Successive enantioseparation on a milligram scale of the most representative compounds led to the discovery that (S)-isomers were more potent than their corresponding (R)-enantiomers. Lastly, molecular modeling studies were conducted to define those structural requirements that were responsible for the discrimination among selected human isoforms of carbonic anhydrases. Two nanomolar hCA IX and XII inhibitors were also screened for their selective toxicity against non tumoral primary cells (fibroblasts) and against a breast adenocarcinoma cell line (MCF7) in hypoxic environment. The efficacious combination of these compounds with doxorubicin on MCF7 cells was demonstrated after 72 h of treatment.


Assuntos
Antígenos de Neoplasias/metabolismo , Anidrase Carbônica IX/metabolismo , Inibidores da Anidrase Carbônica/química , Inibidores da Anidrase Carbônica/farmacologia , Anidrases Carbônicas/metabolismo , Sacarina/química , Sacarina/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Anidrase Carbônica IX/antagonistas & inibidores , Inibidores da Anidrase Carbônica/síntese química , Linhagem Celular , Reação de Cicloadição , Humanos , Isoxazóis/síntese química , Isoxazóis/química , Isoxazóis/farmacologia , Células MCF-7 , Simulação de Acoplamento Molecular , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Neoplasias/metabolismo , Sacarina/síntese química
18.
Angew Chem Int Ed Engl ; 59(18): 7029-7034, 2020 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-31958202

RESUMO

Allylation and conjunctive cross-coupling represent two useful, yet largely distinct, reactivity paradigms in catalysis. The union of these two processes would offer exciting possibilities in organic synthesis but remains largely unknown. Herein, we report the use of allyl electrophiles in nickel-catalyzed conjunctive cross-coupling with a non-conjugated alkene and dimethylzinc. The transformation is enabled by weakly coordinating, monodentate aza-heterocycle directing groups that are useful building blocks in synthesis, including saccharin, pyridones, pyrazoles, and triazoles. The reaction occurs under mild conditions and is compatible with a wide range of allyl electrophiles. High chemoselectivity through substrate directivity is demonstrated by the facile reactivity of the ß-γ alkene of the starting material, whereas the ϵ-ζ alkene of the product is preserved. The generality of this approach is further illustrated through the development of an analogous method with alkyne substrates. Mechanistic studies reveal the importance of the dissociation of the weakly coordinating directing group to allow the allyl moiety to bind and facilitate C(sp3 )-C(sp3 ) reductive elimination.


Assuntos
Compostos Alílicos/química , Níquel/química , Pirazóis/síntese química , Piridonas/síntese química , Sacarina/síntese química , Triazóis/síntese química , Alcenos/química , Alquilação , Catálise , Estrutura Molecular , Compostos Organometálicos/química , Pirazóis/química , Piridonas/química , Sacarina/química , Estereoisomerismo , Triazóis/química
19.
Pharm Dev Technol ; 25(2): 227-236, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31671004

RESUMO

The physicochemical properties and in vivo absorption of a drug can be altered through cocrystallization with a suitable coformer. The aim of this study was to prepare and characterize Gabapentin (Gaba)-saccharine (sacch) sweet cocrystals for improvement of Gaba physicochemical properties, stability and in vivo absorption in addition to masking its taste. The prepared cocrystals were incorporated into oro-dispersible tablets as an attractive dosage form for pediatrics and adults. Gaba-sacch sweet cocrystals were prepared and characterized using FTIR, DSC, XRD and SEM analysis. They enhanced Gaba solubility and particle size distribution. Oro-dispersible tablets of the sweet cocrystals were prepared and evaluated in comparison to tablets prepared by Gaba-sacch physical mixture (PM). The tablets prepared by the cocrystals had lower wetting and disintegration time with enhanced drug release than those prepared with the physical mixture. The optimized formulation was evaluated for Gaba pharmacokinetics in rabbits in comparison to Gaba-sacch PM tablet and Gaba commercial oral capsules. This formulation had enhanced in vivo drug absorption through significant higher Cmax and AUC0-24 with shorter Tmax. The prepared Gaba-sacch sweet cocrystals oro-dispersible tablets, in addition to its enhanced in vitro and in vivo performance, can also enhance patient compliance through its palatable taste and ease of administration.


Assuntos
Gabapentina/química , Sacarina/química , Comprimidos/química , Administração Oral , Adulto , Animais , Varredura Diferencial de Calorimetria/métodos , Química Farmacêutica/métodos , Composição de Medicamentos/métodos , Liberação Controlada de Fármacos/efeitos dos fármacos , Feminino , Humanos , Masculino , Coelhos , Solubilidade/efeitos dos fármacos , Paladar/efeitos dos fármacos
20.
Int J Biol Macromol ; 143: 913-921, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31678104

RESUMO

The aim of this paper is to develop a mild and efficient extraction method for polysaccharides from Sinonovacula constricta (SCP) using enzyme extraction, and analyze the structural characteristics and antioxidant activities of the two purified polysaccharide fractions (SCP-1 and SCP-2). Firstly, enzyme extraction conditions were optimized, and the conditions were found to be, as follows: enzymolysis time 173.0 min, pH 8.2, enzymolysis temperature 50.0 ℃ and enzyme content 4.0%. Comparison between enzymatic extraction and water extraction was obtained from visual, UV-visible and IR spectrum images. The results clearly indicate that there is no significant difference between them with regard to the composition of the SCP fraction, but the polysaccharide content produced by enzymatic extraction is higher. Then, the physicochemical properties and structural characteristics of SCP-1 and SCP-2 were investigated using FT-TR, UV, GC and HPGPC. The carbohydrate content, sulfuric radicals and uronic acids of the two fractions were detected. Both SCP-1 and SCP-2 were mainly consisted of glucose, but their molecular weights were different. In addition, compared the Fe2+ chelating activity, ABTS+ radical and superoxide radical scavenging activity, and lipid peroxidation inhibition activity of SCP-1 and SCP-2, it turned out that SCP-2 had stronger antioxidant activity than SCP-1.


Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Bivalves/química , Polissacarídeos/química , Polissacarídeos/farmacologia , Acetaminofen/análogos & derivados , Acetaminofen/química , Análise de Variância , Animais , Fenômenos Químicos , Peso Molecular , Monossacarídeos/química , Polissacarídeos/isolamento & purificação , Sacarina/análogos & derivados , Sacarina/química , Análise Espectral
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