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1.
Carbohydr Polym ; 227: 115356, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590850

RESUMO

Chitosan oligosaccharide-valylvaline-stearic acid (CSO-VV-SA) nanomicelles were designed for topical ocular drug delivery, based on peptide transporter-1 (PepT-1) active targeting. Hydrogenated castor oil-40/octoxynol-40 (HCO-40/OC-40) mixed nanomicelles were also prepared according to Cequa, just approved by FDA. Both nanomicelles produced no significant cytotoxicity and difference in human corneal epithelial cells (HCEpiC) and human conjunctival epithelial cells (HConEpiC). The active transport of CSO-VV-SA nanomicelles by PepT-1 was illustrated in the inhibitory test. Ex vivo fluorescence images of frozen sections indicated that the nanomicelles entered the posterior segment mainly through conjunctival route. In vivo precorneal retention study suggested dexamethasone from both nanomicelles could be detected for more than 3 h in rabbit tears. In vivo distribution evaluation of rabbits' eyes showed the delivering efficiency of CSO-VV-SA nanomicelles was not inferior to that of HCO-40/OC-40 mixed nanomicelles. These findings indicated that CSO-VV-SA nanomicelles could become promising candidates for further clinical application.


Assuntos
Anti-Inflamatórios/administração & dosagem , Quitosana/administração & dosagem , Dexametasona/administração & dosagem , Sistemas de Liberação de Medicamentos , Micelas , Nanopartículas/administração & dosagem , Oligossacarídeos/administração & dosagem , Administração Oftálmica , Animais , Anti-Inflamatórios/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Quitosana/química , Dexametasona/química , Dipeptídeos/administração & dosagem , Dipeptídeos/química , Liberação Controlada de Fármacos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Olho/citologia , Olho/metabolismo , Humanos , Masculino , Nanopartículas/química , Oligossacarídeos/química , Transportador 1 de Peptídeos/metabolismo , Coelhos , Ratos Sprague-Dawley , Ácidos Esteáricos/administração & dosagem , Ácidos Esteáricos/química
2.
Food Chem ; 303: 125396, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31446365

RESUMO

This study describes the determination of lead at trace levels by slotted quartz tube flame atomic absorption spectrophotometry (SQT-FAAS) after preconcentration by the help of stearic acid coated magnetic nanoparticle (SAC-MNPs) based sonication assisted dispersive solid phase extraction (SA-DSPE). SAC-MNPs were used due to their easy separation advantages by the application of external magnetic field. All extraction parameters were optimized by response surface methodology based experimental design. The experimented data was evaluated by the analysis of variance. Under the optimum conditions, about 31 folds enhancement in detection power was obtained over the conventional FAAS. The recovery results obtained for samples spiked at 60 and 120 ng mL-1 were 106.6 and 102.6%, respectively, validating the method as accurate and applicable to the red pepper matrix. The percent relative standard deviations of the results were under 5.0% even at low concentrations that established high precision for replicate extractions and instrumental readings.


Assuntos
Capsicum/química , Chumbo/análise , Chumbo/isolamento & purificação , Microextração em Fase Líquida/métodos , Magnetismo/métodos , Extração em Fase Sólida/métodos , Espectrofotometria Atômica/métodos , Contaminação de Alimentos/análise , Frutas/química , Magnetismo/instrumentação , Nanopartículas de Magnetita/química , Quartzo/química , Sensibilidade e Especificidade , Sonicação , Ácidos Esteáricos/química
3.
Int J Nanomedicine ; 14: 9453-9467, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31819443

RESUMO

Background: Ovarian cancer is a common malignancy in the female reproductive system with a high mortality rate. The most important reason is multidrug resistance (MDR) of cancer chemotherapy. To reduce side effects, reverse resistance and improve efficacy for the treatment of ovarian cancer, a "core-shell" polymeric nanoparticle-mediated curcumin and paclitaxel co-delivery platform was designed. Methods: Nuclear magnetic resonance confirmed the successful grafting of polyethylenimine (PEI) and stearic acid (SA) (PEI-SA), which is designed as a mother core for transport carrier. Then, PEI-SA was modified with hyaluronic acid (HA) and physicochemical properties were examined. To understand the regulatory mechanism of resistance and measure the anti-tumor efficacy of the treatments, cytotoxicity assay, cellular uptake, P-glycoprotein (P-gp) expression and migration experiment of ovarian cancer cells were performed. In addition, adverse reactions of nanoformulation to the reproductive system were examined. Results: HA-modified drug-loaded PEI-SA had a narrow size of about 189 nm in diameters, and the particle size was suitable for endocytosis. The nanocarrier could target specifically to CD44 receptor on the ovarian cancer cell membrane. Co-delivery of curcumin and paclitaxel by the nanocarriers exerts synergistic anti-ovarian cancer effects on chemosensitive human ovarian cancer cells (SKOV3) and multi-drug resistant variant (SKOV3-TR30) in vitro, and it also shows a good anti-tumor effect in ovarian tumor-bearing nude mice. The mechanism of reversing drug resistance may be that the nanoparticles inhibit the efflux of P-gp, inhibit the migration of tumor cells, and curcumin synergistically reverses the resistance of PTX to increase antitumor activity. It is worth noting that the treatment did not cause significant toxicity to the uterus and ovaries with the observation of macroscopic and microscopic. Conclusion: This special structure of targeting nanoparticles co-delivery with the curcumin and paclitaxel can increase the anti-tumor efficacy without increasing the adverse reactions as a promising strategy for therapy ovarian cancer.


Assuntos
Curcumina/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Neoplasias Ovarianas/tratamento farmacológico , Paclitaxel/uso terapêutico , Polímeros/química , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Curcumina/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Humanos , Ácido Hialurônico/química , Concentração Inibidora 50 , Camundongos Endogâmicos BALB C , Camundongos Nus , Micelas , Nanopartículas/química , Nanopartículas/ultraestrutura , Neoplasias Ovarianas/patologia , Paclitaxel/farmacologia , Polietilenoimina/química , Ácidos Esteáricos/química , Distribuição Tecidual , Resultado do Tratamento
4.
Molecules ; 24(20)2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31619025

RESUMO

9-Hydroxystearic acid (9-HSA) is an endogenous cellular lipid that possesses antiproliferative and selective effects against cancer cells. A series of derivatives were synthesized in order to investigate the effect of the substituent in position 9 and on the methyl ester functionality on the biological activity. The two separate enantiomers of methyl 9-hydroxystearate and of methyl 9-aminostearate showed antiproliferative activity against the HT29 cell line. This indicates the importance of position 9 groups being able to make hydrogen bonding with the molecular target. Further, this effect must be preserved when the carboxy group of 9-HSA is esterified. The biological tests showed that the amines, contrarily to methyl esters, resulted in cytotoxicity. A deep investigation on the effect of methyl (R)-9-hydroxystearate on HT29 cells showed an antiproliferative effect acting through the CDKN1A and MYCBP gene expression.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Ácidos Esteáricos/síntese química , Ácidos Esteáricos/farmacologia , Antineoplásicos/química , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células HT29 , Humanos , Estrutura Molecular , Ácidos Esteáricos/química , Relação Estrutura-Atividade
5.
Bioengineered ; 10(1): 397-408, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31526157

RESUMO

Nowadays, there is an increasing concern toward substituting the scarce wood fibers with alternative lignocellulosic fibers that originate from crop residue to reinforce biocomposites. In this paper, the potential application of coffee hull (CH) of the reinforced polyethylene (PE) matrix composites was studied for the first time. Experiments of composite that enhanced with CH on mechanical properties, hydroscopicity, thermogravimetric analysis, fiber treatment, and microstructures were tested in this study. The PE matrix was reinforced with varying volume fractions of CH and was studied. The results show that incorporation of coffee hull markedly improved the mechanical properties of the reinforced high-density polyethylene (HDPE) matrix composites. Micrographs show a strong interfacial adhesion between the CH fiber particles. This property may be the main reason for the stability between composites. At the same time this work investigated the effect of different treatments on the mechanical properties and water absorption behavior of composites. The fiber surface treatments were done using active chemicals such as calcium hydroxide (Ca(OH)2), silane coupling agent (SCA), maleic anhydride grafted polypropylene (MA-g-PP), stearic acid (SA), ethylene bis stearamide (EBS) and the combination (MA-g-PP, SA, EBS). The results show that (Ca(OH)2)treatment is the best way to improve its properties. Probably because attributed to removal of surface active functional groups (-OH) from the CH fiber and induction of hydrophobicity that in turn improved the compatibility with the polymer matrix. As a result, the use of coffee hull in composites could have great significance for the industry.


Assuntos
Café/química , Manufaturas , Plásticos/síntese química , Polietileno/química , Hidróxido de Cálcio/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Anidridos Maleicos/química , Teste de Materiais , Plásticos/química , Silanos/química , Ácidos Esteáricos/química , Temperatura Ambiente , Resistência à Tração , Resíduos , Molhabilidade
6.
Mater Sci Eng C Mater Biol Appl ; 105: 110107, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546448

RESUMO

Recently, chemotherapy is still widely exploited to treat the residual, infiltrative tumor cells after surgical resection. However, many anticancer drugs are limited in clinical application due to their poor water-solubility (hydrophibic) and stability, low bioavailability, and unfavorable pharmacokinetics. Herein, an amphiphilic stearic acid-O-carboxymethyl chitosan (SA-CMC) conjugate was synthesized by amide linkage of SA to the backbone of CMC polymer and then self-assembled into nanoparticles (SA-CMC NPs) with the hydrodynamic particle size of ~100 nm. Subsequently, Paclitaxel (PTX) as a potent and broad-spectrum anticancer drug was loaded into SA-CMC NPs by a probe sonication combined with dialysis method. Owing to the multi-hydrophobic inner cores, the prepared PTX-SA-CMC NPs showed a considerable drug-loading capacity of ~19 wt% and a biphasic release behavior with an accumulative release amount in the range of 70-90% within 72 h. PTX-SA-CMC NPs remarkably enhanced the accumulation at the tumor sites by passive targeting followed by cellular endocytosis. Upon the stimuli of acid, PTX-SA-CMC NPs showed exceptional instability by pH change, thereby triggering the rapid disassembly and accelerated drug release. Consequently, compared with Cremophor EL-based free PTX treatment, PTX-SA-CMC NPs under pH-stimuli accomplished highly efficient apoptosis in cancer cells and effectively suppression of tumors by chemotherapy. Overall, PTX-SA-CMC NPs integrating imaging capacity might be a simple yet feasible PTX nanosystem for tumor-targeted delivery and cancer therapy.


Assuntos
Antineoplásicos , Quitosana , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Ácidos Esteáricos , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Quitosana/química , Quitosana/farmacocinética , Quitosana/farmacologia , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/farmacologia , Feminino , Humanos , Concentração de Íons de Hidrogênio , Neoplasias Hepáticas Experimentais/metabolismo , Camundongos , Camundongos Nus , Ácidos Esteáricos/química , Ácidos Esteáricos/farmacocinética , Ácidos Esteáricos/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Int J Nanomedicine ; 14: 6425-6437, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31496695

RESUMO

Introduction: Curcumin (CUR) is a general ingredient of traditional Chinese medicine, which has potential antitumor effects. However, its use clinically has been limited due to its low aqueous solubility and bioavailability. In order to improve the therapeutic effect of CUR on osteosarcoma (i.e., bone cancer), a multifunctional micelle was developed here by combining active bone accumulating ability with tumor CD44 targeting capacity. Methods: The CUR loaded micelles were self-assembled by using alendronate-hyaluronic acid-octadecanoic acid (ALN-HA-C18) as an amphiphilic material. The obtained micelles were characterized for size and drug loading. In addition, the in vitro release behavior of CUR was investigated under PBS (pH 5.7) medium containing 1% Tween 80 at 37℃. Furthermore, an hydroxyapatite (the major inorganic component of bone) affinity experiment was studied. In vitro antitumor activity was evaluated. Finally, the anti-tumor efficiency was studied. Results: The size and drug loading of the CUR loaded ALN-HA-C18 micelles were about 118 ± 3.6 nm and 6 ± 1.2%, respectively. CUR was released from the ALN-HA-C18 micelles in a sustained manner after 12 h. The hydroxyapatite affinity experiment indicated that CUR loaded ALN-HA-C18 micelles exhibited a high affinity to bone. CUR loaded ALN-HA-C18 micelles exhibited much higher cytotoxic activity against MG-63 cells compared to free CUR. Finally, CUR loaded ALN-HA-C18 micelles effectively delayed anti-tumor growth properties in osteosarcoma bearing mice as compared with free CUR. Conclusion: The present study suggested that ALN-HA-C18 is a novel promising micelle for osteosarcoma targeting and delivery of the hydrophobic anticancer drug CUR.


Assuntos
Alendronato/uso terapêutico , Curcumina/uso terapêutico , Sistemas de Liberação de Medicamentos , Ácido Hialurônico/química , Micelas , Osteossarcoma/tratamento farmacológico , Ácidos Esteáricos/química , Alendronato/química , Animais , Antineoplásicos/uso terapêutico , Neoplasias Ósseas/tratamento farmacológico , Linhagem Celular Tumoral , Curcumina/química , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Humanos , Masculino , Camundongos Nus , Osteossarcoma/patologia , Tamanho da Partícula , Polímeros/química , Espectroscopia de Prótons por Ressonância Magnética
8.
Molecules ; 24(15)2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31390777

RESUMO

(R)-9-hydroxystearic acid, (R)-9-HSA, is a chiral nonracemic hydroxyacid of natural origin possessing interesting properties as an antiproliferative agent against different cancer types. Considering its potential application for medical and pharmaceutical purposes, the structures and rheological properties of (R)-9-HSA were investigated. Oscillatory rheology measurements reveal that (R)-9-HSA gels only paraffin oil, with less efficiency and thermal stability than its positional isomer (R)-12-HSA. Conversely, (R)-9-HSA affords crystals from methanol, acetonitrile, and carbon tetrachloride. The single crystal structures obtained both at 293 K and 100 K show non-centrosymmetric twisted carboxylic acid dimers linked at the midchain OHs into long, unidirectional chains of hydrogen bonds, owing to head-tail ordering of the molecules. Synchrotron X-ray powder diffraction experiments, performed on the solids obtained from different solvents, show the occurrence of polymorphism in paraffin oil and through thermal treatment of the solid from methanol.


Assuntos
Ácidos Esteáricos/química , Cristalografia por Raios X , Ligações de Hidrogênio , Modelos Moleculares , Estrutura Molecular , Reologia , Solventes/química , Análise Espectral , Difração de Raios X
9.
Drug Dev Ind Pharm ; 45(10): 1674-1681, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31378098

RESUMO

Objective: The main objective of this research is to develop an immediate release Rupatadine fumarate 10 mg tablets formulation by direct compression, through a Quality by Design approach in Costa Rica. Methods: According to a Quality by Design approach; Target Product Profile, Quality Target Product Profile, and the Critical Quality Attributes were defined. In the preformulation study, compatibility tests were carried out between the raw materials. The Critical Material Attributes were established using Quality Risk Management. Three formulation prototypes were prepared by direct compression and its Critical Process Parameters were defined. The analysis of the prototypes was realized in terms of organoleptic properties, identification, potency, content uniformity, dissolution, disintegration, friability and loss by drying. Results: All the prototypes showed a white or slightly pink surface, potency between 90.0 -110.0 % of the labeling, an acceptance value for the content uniformity lower than the specification (AV < 15), the dissolved amount of active pharmaceutical ingredient was greater than 85.0 % at 30 minutes, friability less than 1.0 %, a disintegration time less than 15 minutes and moisture content less than 2.0 %. Conclusions: The approaching of a Quality by Design model to the current development allowed to obtain satisfactory results in the three formulation prototypes. The excipients to be used can be lactose monohydrate, microcrystalline cellulose, sodium croscarmellose, pregelatinized starch, magnesium stearate, stearic acid, and PVP K-30.


Assuntos
Ciproeptadina/análogos & derivados , Fumaratos/química , Comprimidos/química , Carboximetilcelulose Sódica/química , Celulose/química , Química Farmacêutica/métodos , Ciproeptadina/química , Composição de Medicamentos/métodos , Excipientes/química , Lactose/química , Solubilidade/efeitos dos fármacos , Amido/química , Ácidos Esteáricos/química , Tecnologia Farmacêutica/métodos
10.
AAPS PharmSciTech ; 20(7): 290, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31428895

RESUMO

Dosage forms with increased gastric residence time are promising tools to increase bioavailability of drugs with narrow absorption window. Low-density floating formulations could avoid gastric emptying; therefore, sustained drug release can be achieved. Our aim was to develop a new technology to produce low-density floating formulations by melt foaming. Excipients were selected carefully, with the criteria of low gastric irritation, melting range below 70°C and well-known use in oral drug formulations. PEG 4000, Labrasol and stearic acid type 50 were used to create metronidazole dispersion which was foamed by air on atmospheric pressure using in-house developed apparatus at 53°C. Stearic acid was necessary to improve the foamability of the molten dispersion. Additionally, it reduced matrix erosion, thus prolonging drug dissolution and preserving hardness of the moulded foam. Labrasol as a liquid solubiliser can be used to increase drug release rate and drug solubility. Based on the SEM images, metronidazole in the molten foam remained in crystalline form. MicroCT scans with the electron microscopic images revealed that the foam has a closed-cell structure, where spherical voids have smooth inner wall, they are randomly dispersed, while adjacent voids often interconnected with each other. Drug release from all compositions followed Korsmeyer-Peppas kinetic model. Erosion of the matrix was the main mechanism of the release of metronidazole. Texture analysis confirmed that stearic acid plays a key role in preserving the integrity of the matrix during dissolution in acidic buffer. The technology creates low density and solid matrix system with micronsized air-filled voids.


Assuntos
Formas de Dosagem , Temperatura Alta , Metronidazol/química , Estômago , Disponibilidade Biológica , Preparações de Ação Retardada , Composição de Medicamentos , Liberação Controlada de Fármacos , Excipientes/química , Esvaziamento Gástrico , Metronidazol/farmacocinética , Solubilidade , Ácidos Esteáricos/química
11.
Int J Pharm ; 568: 118504, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31299339

RESUMO

Co-jet-milling drugs and lubricants may enable simultaneous particle size reduction and surface coating to achieve satisfactory aerosolization performance. This study aims to establish the relationship between surface lubricant coverage and aerosolization behavior of a model drug (ciprofloxacin HCl) co-jet-milled with lubricants [magnesium stearate (MgSt) or l-leucine]. The co-jet-milled formulations were characterized for particle size, morphology, cohesion, Carr's index, and aerosolization performance. The surface lubricant coating was assessed by probing surface chemical composition using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary-ion mass spectrometry (ToF-SIMS). The effects of co-jet-milling on the surface energy and in vitro dissolution of ciprofloxacin were also evaluated. Our results indicated that, in general, the ciprofloxacin co-jet-milled with l-leucine at >0.5% w/w showed a significant higher fine particle fraction (FPF) compared with the ciprofloxacin jet-milled alone. The FPF values plateau at or above 5% w/w for both MgSt and l-leucine. We have established the quantitative correlations between surface lubricant coverage and aerosolization in the tested range for each of the lubricants. More importantly, our results suggest different mechanisms to improve aerosolization for MgSt-coating and l-leucine-coating, respectively: MgSt-coating reduces inter-particulate interactions through the formation of low surface energy coating films, while l-leucine-coating not only reduces the surface energy but also creates rough particle surfaces that reduce inter-particulate contact area. Furthermore, surface coatings with 5% w/w MgSt (which is hydrophobic) did not lead to substantial changes in in vitro dissolution. Our findings have shown that the coating structure/quality and their effects could be highly dependent on the process and the coating material. The findings from this mechanistic study provide fundamental understanding of the critical effects of MgSt and l-leucine surface coverages on aerosolization and powder flow properties of inhalation particles.


Assuntos
Antibacterianos/química , Ciprofloxacino/química , Inaladores de Pó Seco , Leucina/química , Lubrificantes/química , Ácidos Esteáricos/química , Aerossóis , Composição de Medicamentos , Liberação Controlada de Fármacos , Excipientes/química , Tamanho da Partícula , Pós , Propriedades de Superfície
12.
Int J Pharm ; 569: 118525, 2019 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-31319146

RESUMO

Many studies on continuous twin-screw granulation only focus on the granulator without linking this process step to the upstream and downstream unit operations. Product critical quality attributes (CQAs) are however not only determined by the granulation step. In this study, the possibility to manage the batch-to-batch variability of an active pharmaceutical ingredient (API) in a high drug loaded formulation on a continuous line was investigated to obtain consistent tablet CQAs. As the ultimate goal of continuous manufacturing is to produce 24/7, current study also aimed at guaranteeing long term stability of the process. To do so, previously identified API critical material attributes (CMAs) were varied together with granulation, drying and milling critical process parameters (CPPs) in a screening design of experiments to understand the influence of these factors upon product CQAs and process stability. To evaluate the factors affecting the process stability with a reduced amount of materials, process deviations recorded by process sensors were used. While product CQAs only depended on process CPPs, process stability was strongly affected by API CMAs. The effect of API batch-to-batch variability on process stability could nonetheless be managed by applying suitable granulation conditions. Therefore, appropriate ranges of CPPs were defined to ensure both product CQAs and process stability. By studying the fully integrated continuous manufacturing line, it was possible to highlight the interactions between the different unit operations and the API CMAs and to design a robust process.


Assuntos
Controle de Qualidade , Tecnologia Farmacêutica , Celulose/análogos & derivados , Celulose/química , Excipientes/química , Tamanho da Partícula , Povidona/química , Reologia , Dióxido de Silício/química , Ácidos Esteáricos/química , Comprimidos
13.
Int J Pharm ; 568: 118522, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31319149

RESUMO

Magnesium stearate is an extremely common pharmaceutical excipient and the measurement of BET surface area via nitrogen adsorption is undertaken during pharmaceutical formulation and manufacture. In this paper, four commercial magnesium stearate materials in mono- and di-hydrated forms are analysed by nitrogen and krypton adsorption for the calculation of BET surface area. BET surface area via nitrogen adsorption is shown to be erroneously high due to a structural swelling and adsorbate encapsulation effect occurring throughout the BET range and which should preclude the use of BET theory. However, with krypton adsorption this effect commences at higher adsorption pressures and it is possible to calculate BET surface area which better represents the true surface area of the material. The disparity between nitrogen and krypton adsorption is greater for the di-hydrate form: the mean average BET surface area of 10 samples from the same di-hydrate containing batch are 23.18 m2g-1 via nitrogen adsorption and 6.78 m2g-1 via krypton. It is also shown than the standard deviation of BET surface area across 10 analyses of each of the four batches is considerably lower via krypton adsorption. Finally, an analytical protocol for krypton adsorption onto magnesium stearate for BET surface area measurement is established.


Assuntos
Ácidos Esteáricos/química , Adsorção , Criptônio/química , Nitrogênio/química , Propriedades de Superfície
14.
Molecules ; 24(13)2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31269674

RESUMO

Composites of polyolefin matrices (HDPE and PP) were prepared by melt processing using two commercially available nano ZnO powders (Zinkoxyd aktiv and Zano 20). The mechanical and thermal properties, UV-Vis stability, and antibacterial activity of composites were studied. Tensile testing revealed that both nano ZnO types have no particular effect on the mechanical properties of HDPE composites, while some positive trends are observed for the PP-based composites, but only when Zano 20 was used as a nanofiller. Minimal changes in mechanical properties of composites are supported by an almost unaffected degree of crystallinity of polymer matrix. All polyolefin/ZnO composites exposed to artificial sunlight for 8-10 weeks show more pronounced color change than pure matrices. This effect is more evident for the HDPE than for the PP based composites. Color change also depends on the ZnO concentration and type; composites with Zano 20 show more intense color changes than those prepared with Zinkoxyd aktiv. Results of the antibacterial properties study show very high activity of polyolefin/ZnO composites against Staphylococcus aureus regardless of the ZnO surface modification, while antibacterial activity against Escherichia coli shows only the composites prepared with unmodified ZnO. This phenomenon is explained by different membrane structure of gram-positive (S. aureus) and gram-negative (E. coli) bacteria.


Assuntos
Química Orgânica/métodos , Polienos/química , Óxido de Zinco/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Nanopartículas/química , Nanopartículas/ultraestrutura , Silanos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Ácidos Esteáricos/química , Propriedades de Superfície , Resistência à Tração , Difração de Raios X
15.
Int J Pharm ; 568: 118541, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31330172

RESUMO

In the present study the application of near-infrared chemical imaging (NIR-CI) for assessing particle segregation in granules from continuous twin screw granulation (TSG) granules, were the complex attributes of the machinery configuration in relation to particle segregation is not well understood was investigated. Experiments were performed along the compartmental length of the TSG barrel channel by varying the screw element type and liquid binder viscosity. Examination of the data showed a direct correlation between dispersion due to shear force and de-mixing of particles, which allowed for identification of fundamental granule segregation mechanisms affecting content uniformity in TSG. Particle segregation behavior was linked to dispersion due to shear force through a proposed regime mapping approach which links de-mixing potential to controlling granule formation mechanisms with a new dimensionless mixing number. This was carried out in order to provide a general guideline of how particles segregate along the length of the TSG barrel channel.


Assuntos
Tecnologia Farmacêutica/métodos , Lactose/química , Tamanho da Partícula , Pós , Ácidos Esteáricos/química
16.
Pharm Dev Technol ; 24(9): 1181-1185, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31354002

RESUMO

In this work, we report the development and optimization of solid lipid nanoparticles (SLN) production by a simple, fast, and cost-effective high shear homogenization process. A screening of several solid lipids (Compritol 888 ATO, Precirol ATO 5, Cetyl Palmitate, Dynasan 118, Imwitor 900K, Stearic acid) has been carried out in combination with Poloxamer 188 as the selected surfactant, based on the mean particle size and polydispersity index. The improvement of the physical stability of the SLN dispersions was achieved by the use of a cationic lipid (cetyl trimethylammonium bromide) reaching zeta potential values above +60 mV. Combining the optimized speed and time of shear, monodispersed SLN (PdI < 0.25) under the nanometer range could be produced.


Assuntos
Lipídeos/química , Nanopartículas/química , Poloxâmero/química , Tensoativos/química , Diglicerídeos/química , Portadores de Fármacos/química , Composição de Medicamentos , Ácidos Graxos/química , Palmitatos/química , Tamanho da Partícula , Ácidos Esteáricos/química
17.
AAPS PharmSciTech ; 20(7): 269, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31350661

RESUMO

Process analytical technologies are implemented within the pharmaceutical manufacturing process to rectify issues associated with current sampling methods. These include inline monitoring methods such as passive vibration measurements which are non-intrusive and less costly to other methods. In the final mixing stage of the tablet manufacturing process, a lubricant is added to ensure the mixture is ejected from the tablet die cleanly. To monitor this process, an accelerometer was attached to the lid of the V-blender loaded with various particles and magnesium stearate. At a fixed fill level, the lubricant concentration and particle mass were varied to investigate the effects of changes in process parameters on the signal vibrations measured by the sensor, the coefficient of restitution, and the flowability. It was found that measured vibrations from stress waves propagated upon collisions of the particles with the V-shell respond to and can distinguish differences in particles. As well, the magnesium stearate layer around particles alters energy dissipation and subsequently the measured vibrations. A mixing endpoint of uniform distribution of magnesium stearate with primary particles can be identified from vibrations measured by an accelerometer attached to the lid of the V-blender. The flowability change was considered negligible in the particles due to their physical morphology. These findings indicate that passive vibration measurements can be a viable, non-intrusive monitoring method while providing insight into V-blender mixing behaviors as well as improving process efficiency.


Assuntos
Química Farmacêutica , Vibração , Excipientes , Lubrificantes , Ácidos Esteáricos/química , Comprimidos
18.
Food Chem ; 300: 125219, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31351259

RESUMO

Although storage temperature is important for partial coalescence, the literature is scant on exploring the partial coalescence behavior between refrigerated and room temperature storage. In this study, comparison of the partial coalescence behavior between 4 and 20 °C was investigated towards corresponding oil-in-water emulsions, and subsequently towards the ultimate properties of the aerated colloidal system. As expected, compared to the value of Avrami constant (K) at 20 °C, the value of palm kernel stearin (PKS85) and mixtures of PKS85 and glycerol monostearate (PKS85-GMS) obtained at 4 °C increased by 22 and 14 times, respectively. PKS85 and PKS85-GMS displayed the needlelike appearance (N-type crystal) with a little layer crystal (L-type crystal) at 4 °C and spherical shape formed by L-type crystal along with granular crystal at 20 °C. Interestingly, several unstable air bubbles with irregularly-shape were observed in the aerated emulsions at 20 °C, while these emulsions at 4 °C displayed numerous rounded and uniform air bubbles with glossy surface. This was attributed to the sufficient stiff needle crystals at 4 °C, facilitating the coalescence of fat globules via liquid fat bridges, further forming a rigid crystal-based network and trapping the air bubbles. Therefore, our findings gained an insight into the partial coalescence behavior in emulsion, providing theoretical support for designing and optimizing the production process of foam structure products.


Assuntos
Emulsões/química , Armazenamento de Alimentos/métodos , Ar , Cristalização , Óleo de Palmeira/química , Ácidos Esteáricos/química , Temperatura Ambiente , Água/química
19.
Biophys Chem ; 252: 106223, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31325894

RESUMO

Simulations of electron paramagnetic resonance spectra of stearic acid spin labels in lipid bilayers are used to illustrate the fact that the apparent order parameter Sapp calculated from the spectral shape does not coincide with the true order parameter S in the case of slow motions. While S reflects a static property as the degree of order of the lipid chains, Sapp depends on both order and dynamics. Thus, calibration procedures intended to obtain bilayer microviscosity values from Sapp in the slow motion regime are not reliable. However, Sapp is a useful tool to describe trends in membrane fluidity.


Assuntos
Bicamadas Lipídicas/química , Ácidos Esteáricos/química , Espectroscopia de Ressonância de Spin Eletrônica , Estrutura Molecular , Marcadores de Spin , Viscosidade
20.
Drug Des Devel Ther ; 13: 1947-1956, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31239645

RESUMO

Purpose: We aimed to prepare two oral drug delivery systems consisting of polyoxyl 15 hydroxystearate (HS15) with pluronicF127 (F127) and HS15 with pluronicL61 (L61) to overcome the challenges of genistein's poor oral bioavailability. This provides a good strategy for enhancing the potential value of genistein. Methods: We designed two binary mixed micelle systems employing the organic solvent evaporation method using surfactants (HS15, L61, and F127). Formulations (GEN-F and GEN-L) were characterized by transmission electron microscopy. Drug content analysis, including entrapment efficiency (EE%), drug loading (DL%), and the cumulative amount of genistein released from the micelles, was performed using HPLC. The permeability of optimum formulation was measured in Caco-2 cell monolayers, and the oral bioavailability was evaluated in SD rats. Results: The solutions of GEN-F and GEN-L were observed to be transparent and colorless. GEN-F had a lower EE% of 80.79±0.55% and a DL% of 1.69±0.24% compared to GEN-L, which had an EE% 83.40±1.36% and a DL% 2.26±0.18%. TEM results showed that the morphology of GEN-F and GEN-L was homogeneous and resembled a spherical shape. The dilution and storage conditions had no significant effect on particle size and EE%. Genistein demonstrated a sustained release behavior when encapsulated in micelles. Pharmacokinetics study showed that the relative oral bioavailability of GEN-F and GEN-L increased by 2.23 and 3.46 fold while also enhancing the permeability of genistein across a Caco-2 cell monolayer compared to that of raw genistein. Conclusion: GEN-F and GEN-L as a drug delivery system provide an effective strategy for enhancing and further realizing the potential value of GEN.


Assuntos
Sistemas de Liberação de Medicamentos , Genisteína/administração & dosagem , Genisteína/farmacocinética , Micelas , Poloxâmero/química , Polietilenoglicóis/química , Ácidos Esteáricos/química , Administração Oral , Animais , Disponibilidade Biológica , Células CACO-2 , Células Cultivadas , Liberação Controlada de Fármacos , Humanos , Masculino , Tamanho da Partícula , Poloxâmero/administração & dosagem , Polietilenoglicóis/administração & dosagem , Ratos , Ratos Sprague-Dawley , Ácidos Esteáricos/administração & dosagem , Propriedades de Superfície
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