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1.
Artículo en Inglés | MEDLINE | ID: mdl-34370690

RESUMEN

Large randomized clinical trials in severe Coronavirus Disease 2019 (COVID-19) patients have proven efficacy of intravenous tocilizumab. Our aim was to describe the laboratory parameters predicting in-hospital mortality of patients with tocilizumab administration in COVID-19 associated cytokine release syndrome (CRS).We evaluated high-dose (8 mg/kg) intravenous tocilizumab administration in severe and critically ill COVID-19 adult patients fulfilling predefined strict CRS criteria. A single-centre, prospective, observational cohort study was carried out among consecutive adult (≥18 years of age) in-patients with COVID-19 between April 1 and December 31, 2020. The primary endpoint was 28-day all-cause mortality. The changes in laboratory parameters from baseline on day 7 and 14 after administration of tocilizumab were analysed.In total, 1801 patients were admitted to our centre during the study period. One hundred and six patients received tocilizumab, and among them 62 (58.5%) required intensive care unit admittance while 25 (23.6%) deceased. At day 7 after tocilizumab administration, inflammatory markers (CRP, IL-6, ferritin) and lactate dehydrogenase (LDH) values were significantly lower among survivors. Subsequently, at day 14, differences of IL-6 and LDH levels has become more pronounced between subgroups. Restoration of absolute lymphocyte count (ALC) by day 7 and 14 was insufficient among patients who died.In our cohort, administration of high-dose tocilizumab for COVID-19 patients with CRS demonstrated clinical and sustained biochemical parameter improvement in 76.4%. In this patient population high and increasing LDH, IL-6, and low ALC levels had a predictive role for mortality.

2.
Nanotechnology ; 28(3): 034001, 2017 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-27934784

RESUMEN

Photoinitiator-free fabrication of poly(ethylene glycol) diacrylate (PEGDA) scaffolds is achieved using a novel three-dimensional (3D) printing method called mask projected excimer laser stereolithography (MPExSL). The spatial resolution of photoinitiator-free curing is suitable for 3D layer-by-layer fabrication with a single layer thickness well controllable at tens to hundreds of microns using 248 nm wavelength for the irradiation. The photoinitiator-free scaffolds are superior compared to their counterparts fabricated by using photoinitiator molecules, showing a higher level of biocompatibility. A release of toxic chemicals from the photoinitiator containing scaffolds is proven by cell proliferation tests. In contrast, no toxic release is found from the photoinitiator-free scaffolds, resulting in the very same level of cell proliferation as the control sample. The demonstration of photoinitiator-free PEGDA scaffolds enables the fabrication of 3D scaffolds with the highest level of biocompatibility for both in vitro and in vivo applications.

3.
Heliyon ; 10(11): e31849, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38845963

RESUMEN

Ultra-precision turning is a crucial process in the manufacturing industry as it helps to produce parts with high dimensional accuracy, surface finish, and tolerance. The process is similar to traditional turning but is carried out under special circumstances to achieve greater precision and surface finish. The process can be applied to conventional structural materials, but the demand for machining hardened steels is increasing. The optimization of ultra-precision turning of AISI D2 using cubic boron nitride (CBN) tools is a crucial aspect in the field of high-quality machining. This study aims to evaluate the performance of the process and identify the optimal parameters that result in the best quality components while using a CBN tool's ultra-precision turning of AISI D2. Ultra-precision turning process factors such as cutting speed, feed, and depth of cut were experimentally investigated to enhance the response output, such as surface roughness and cutting force components. The full factorial experimental design was used for determining the process characteristics under different conditions, and experimental results were applied to search for the optimum response of machining performance. The optimization process was done by combining the hybrid genetic algorithm-response surface methodology (GA-RSM) and the Taguchi-grey relational analysis (GRA) statistical tools. These methods are useful in situations where the relationship between the input variables and the output responses is complex and non-linear. The results showed that a hybrid GA-RSM approach, combined with Taguchi-GRA statistical analysis, can effectively find optimal process parameters, leading to the best combination of surface roughness and cutting force. In hybrid Taguchi - GRA, the optimal cutting conditions were found to be a cutting speed of 175 m/min, a feed of 0.025 mm, and a depth of cut of 0.06 mm. The findings of this study provide valuable insights for the optimization of ultra-precision CBN turning operations, contribute to the development of precision manufacturing technology, and can be used as a reference for similar machining processes.

4.
Int J Infect Dis ; 125: 233-240, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36328291

RESUMEN

OBJECTIVES: Our aim was to compare outcomes of hospitalized adults with severe COVID-19 and cytokine storm treated with tocilizumab or baricitinib. METHODS: A prospective, investigational, real-world study was performed from April 2020 to April 2021 at our center. COVID-19 severity was classified by World Health Organization criteria, and cytokine storm was documented along predefined criteria. Eligible patients were enrolled at diagnosis if they fulfilled a priori inclusion criteria and received standard-of-care plus tocilizumab or baricitinib for >48 hours. Patients were followed per protocol for 28 days post-diagnosis. The primary outcome was all-cause mortality; secondary outcomes were invasive mechanical ventilation and major infectious complications. RESULTS: Of 463 patients, 102/463 (22.1%) received tocilizumab, and 361/463 (77.9%) baricitinib. Baseline characteristics were balanced. At 28 days, there was no difference in all-cause mortality (22/102, 21.6% vs 64/361, 17.7%; P-value = 0.38). Requirement for invasive mechanical ventilation was more frequent after tocilizumab (52/102, 50.9% vs 96/361, 26.6%; P <0.01), rate of major infectious complications was similar (32/102, 31.4% vs 96/361, 26.6%; P-value = 0.34). In logistic regression, the immunomodulatory drug was not retained as a predictor of all-cause mortality. Kaplan-Meier analysis revealed statistically similar survival distributions. CONCLUSION: All-cause mortality was similar between adults treated with baricitinib or tocilizumab for severe COVID-19 with cytokine storm.


Asunto(s)
COVID-19 , Síndrome de Liberación de Citoquinas , Humanos , Adulto , Síndrome de Liberación de Citoquinas/tratamiento farmacológico , COVID-19/complicaciones , SARS-CoV-2 , Estudios Prospectivos , Resultado del Tratamiento
5.
Orv Hetil ; 152(42): 1698-702, 2011 Oct 16.
Artículo en Húngaro | MEDLINE | ID: mdl-21979223

RESUMEN

UNLABELLED: Ureaplasma urealyticum and Mycoplasma hominis have important role among the causative agents of sexually transmitted diseases. AIM: The aim of the study was to determine the frequency and antibiotic resistance of Ureaplasma urealyticum and Mycoplasma hominis in genital samples obtained from patients examined in the Sexually Transmitted Diseases Centre of the Department of Dermatology, Venerology and Dermatooncology, Semmelweis University, Budapest between May 1, 2008 and July 31, 2010. PATIENTS AND METHODS: Samples were taken from the urethra in men and from the cervix and urethra in women by universal swab (Biolab®) into Urea-Myco DUO kit (Bio-Rad®) and were incubated for 48 hours at 37 C°. Antibiotic sensitivity of positive samples was determined in U9 bouillon using SIR Mycoplasma kit (Bio-Rad®). RESULTS: Samples for 4154 patients aged 16-60 years were examined. In 247/4154 samples (6%) U. urealyticum and in 26/4154 samples (0.63%) M. hominis was isolated from the genital tract. Most U. urealyticum and M. hominis strains (75% and 77%, respectively) were cultured from cervix, while the remaining 25%, and 23% from the male and female urethra, respectively. U. urealyticum and M. hominis were most commonly detected in patients aged between 21 and 40 years. The majority of U. urealyticum strains were sensitive to tetracycline (94%), doxycycline (95%), azithromycin (88%) and josamycin (90%), but were resistant to ofloxacin (21%), erythromycin (85%) and clindamycin (79%). Seventy-seven percent of the U. urealyticum strains were simultaneously resistant to erythromycin and clindamycin, suggesting that ex iuvantibus therapies may select cross-resistant strains to both antibiotics. The resistance of M. hominis to clindamycin, doxycycline, ofloxacin and tetracycline varied between 4% and 12 %. CONCLUSIONS: Because none of the strains was sensitive to all examined antibiotics, the antibiotic sensitivity of U. urealyticum and M. hominis strains should be determined. The high rate of ofloxacin, erythromycin and clindamycin resistance should be considered in the therapy of U. urealyticum infections in Hungary. This is the first such a clinical microbiological study in this topic in Hungary.


Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Mycoplasma hominis/efectos de los fármacos , Conducta Sexual , Enfermedades Bacterianas de Transmisión Sexual/tratamiento farmacológico , Ureaplasma urealyticum/efectos de los fármacos , Sistema Urogenital/microbiología , Adolescente , Adulto , Clindamicina/farmacología , Eritromicina/farmacología , Femenino , Humanos , Hungría , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Mycoplasma hominis/aislamiento & purificación , Ofloxacino/farmacología , Enfermedades Bacterianas de Transmisión Sexual/diagnóstico , Enfermedades Bacterianas de Transmisión Sexual/microbiología , Ureaplasma urealyticum/aislamiento & purificación
6.
Int J Pharm ; 586: 119593, 2020 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-32622813

RESUMEN

The effect of different frequencies and waveforms was investigated for the first time on alternating current electrospinning (ACES). PVPVA64, a polyvinylpyrrolidone-vinyl acetate copolymer was selected for the experiments as an important matrix for amorphous solid dispersions but never processed with ACES. It has been proved that ACES could be operated in a wide range of frequencies (40-250 Hz) and using different waveforms (sinusoidal, square, triangle, saw tooth) without significant changes in fiber morphology. Nevertheless, deterioration of the fiber formation process could be also observed especially at high frequencies. The developed PVPVA64-based fibers containing small amounts of additives (polyethylene oxide (PEO) and sodium dodecyl sulfate (SDS)) served as an excellent carrier for spironolactone (SPIR), a poorly soluble antihypertensive drug. As a result of the amorphously dispersed SPIR and the large surface area of the AC electrospun fibers immediate drug release could be achieved.


Asunto(s)
Electricidad , Polietilenglicoles , Liberación de Fármacos , Polímeros , Povidona , Solubilidad
7.
Artículo en Inglés | MEDLINE | ID: mdl-31863572

RESUMEN

Recently, electrospinning (ES) of fibers has been shown to be an attractive strategy for drug delivery. One of the main features of ES is that a wide variety of drugs can be loaded into the fibers to improve their bioavailability, to enhance dissolution, or to achieve controlled release. Besides, ES is a continuous technology with low energy consumption, which can make it a very economic production alternative to the widely used freeze drying and spray drying. However, the low production rate of laboratory-scaled ES has limited the industrial application of the technology so far. This article covers the various ES technologies developed for scaled-up fiber production with an emphasis on pharmaceutically relevant examples. The methods used for increasing the productivity are complied, which is followed by a review of specific examples from literature where these technologies are utilized to produce oral drug delivery systems. The different technologies are compared in terms of their basic principles, advantages, and limitations. Finally, the different downstream processing options to prepare tablets or capsules containing the electrospun drug are covered as well. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.


Asunto(s)
Industria Farmacéutica , Nanotecnología , Sistemas de Liberación de Medicamentos , Humanos , Nanofibras/química
8.
Acta Vet Hung ; 57(4): 477-84, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19897452

RESUMEN

A haemangioma developing in the wall of the oesophagus and protruding into its cavity is reported for the first time from a Red-eared Slider (Trachemys scripta elegans). As the tumour mechanically hampered swallowing, the animal was unable to eat and consequently developed a poor condition. Histopathology of the tumour revealed all characteristics of a haemangioma: the blood-filled blood-vessels having an irregular cross-section were lined with endothelial cells. Claudin-5 immunohistochemical antibodies were employed for characterising the tumour, and this examination confirmed our initial diagnosis of a haemangioma.


Asunto(s)
Neoplasias Esofágicas/veterinaria , Hemangioma/veterinaria , Tortugas , Animales , Neoplasias Esofágicas/patología , Hemangioma/patología , Masculino
9.
Zookeys ; (824): 71-86, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30799973

RESUMEN

A new, critically endangered species of softshell turtle, Pelodiscusvariegatus sp. n. is described from north-central Vietnam and Hainan Island, China, distinguished by a unique set of genetic and morphological traits from all other congeners (P.axenaria, P.maackii, P.parviformis, P.sinensis, and unnamed genetic lineages). Morphologically, P.variegatus is characterized, among others, by its strong ventral ornamentation in all age classes.

10.
Int J Pharm ; 561: 219-227, 2019 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-30844423

RESUMEN

Corona alternating current electrospinning (C-ACES), a scaled-up productivity electrospinning method was developed by combining the intense forces of the alternating electrostatic field and a sharp-edged spinneret design with increased free surface. C-ACES reached two orders of magnitude higher productivity (up to 1200 mL/h) than the classical single needle direct current electrospinning (DCES) without any alteration of fiber properties. Polyvinylpyrrolidone K90 (PVPK90), a water soluble high molecular weight nonionic polymer was processed for the first time with single needle alternating current electrospinning (ACES) and C-ACES in order to prepare fast dissolving amorphous solid dispersions of spironolactone (SPIR), a poorly water-soluble antihypertensive model drug. The limited spinnability of PVPK90 with AC high voltage could only be resolved by optimizing the solution conductivity with organophilic salts such as sodium dodecyl sulfate (SDS) demonstrating the importance of conductivity during ACES. The effects of varied solution properties (composition and conductivity) and scaling-up were investigated by SEM imaging. Solid state analyses revealed that SPIR was dispersed in an amorphous form in the fibrous mats. In vitro dissolution tests showed ultrafast drug release in case of the amorphous formulations even when prepared with scaled-up C-ACES. Besides the enhancement of conductivity SDS also prevents SPIR from precipitation from the dissolution media due to its solubilization ability.


Asunto(s)
Eficiencia , Electricidad , Tecnología Farmacéutica/métodos , Portadores de Fármacos/química , Composición de Medicamentos/métodos , Liberación de Fármacos , Povidona/química , Espironolactona/química
11.
Eur J Pharm Sci ; 130: 91-99, 2019 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-30684658

RESUMEN

An orally dissolving web (ODW) formulation of poorly soluble carvedilol (CAR) was developed and manufactured continuously using electrospinning (ES) as a key technology. Phase solubility tests revealed that hydroxypropyl-ß-cyclodextrin (HPßCD) solubilizer alone cannot ensure sufficient solubility (6.25 mg CAR in 20 mL) in the oral cavity even if citric acid was present to ionize the basic drug. In turn, electrospun amorphous nanofibers of polyvinylpyrrolidone K30 (PVPK30) and CAR exhibited notable supersaturation of the drug in the presence of citric acid. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) confirmed the amorphous state of CAR. The final ODW was prepared by layering the nanofibers onto pullulan, a well-soluble polysaccharide film carrying citric acid. The double-layered formulation showed ultrafast disintegration and dissolution modeling the oral cavity meeting regulatory requirements (<30 s). The continuous production was accomplished using our recently developed continuous model system by controlled deposition of the nanofibers onto the carrier film strained to a wheel collector and followed by cutting into final dosage units. Performance tests of the continuous system revealed satisfactory content uniformity over time (average acceptance value = 9.45), while residual solvent content measurements showed trace amounts of ethanol (EtOH) after production and acceptable dimethyl-formamide (DMF) content with secondary drying at room temperature. The presented work demonstrates how ES can be part of a continuous manufacturing system as an advanced drying tool during the formulation of challenging drugs.


Asunto(s)
2-Hidroxipropil-beta-Ciclodextrina/síntesis química , Carvedilol/síntesis química , Química Farmacéutica/métodos , Ácido Cítrico/síntesis química , Glucanos/síntesis química , Nanofibras/química , 2-Hidroxipropil-beta-Ciclodextrina/farmacocinética , Rastreo Diferencial de Calorimetría/métodos , Carvedilol/farmacocinética , Ácido Cítrico/farmacocinética , Glucanos/farmacocinética , Solubilidad , Difracción de Rayos X/métodos
12.
Int J Pharm ; 567: 118473, 2019 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-31252149

RESUMEN

The aim of this work was to develop a PAT platform consisting of four complementary instruments for the characterization of electrospun amorphous solid dispersions with meloxicam. The investigated methods, namely NIR spectroscopy, Raman spectroscopy, Colorimetry and Image analysis were tested and compared considering the ability to quantify the active pharmaceutical ingredient and to detect production errors reflected in inhomogeneous deposition of fibers. Based on individual performance the calculated RMSEP values ranged between 0.654% and 2.292%. Mid-level data fusion consisting of data compression through latent variables and application of ANN for regression purposes proved efficient, yielding an RMSEP value of 0.153%. Under these conditions the model could be validated accordingly on the full calibration range. The complementarity of the PAT tools, demonstrated from the perspective of captured variability and outlier detection ability, contributed to model performance enhancement through data fusion. To the best of the author's knowledge, this is the first application of data fusion in the field of PAT for efficient handling of big-analytical-data provided by high-throughput instruments.


Asunto(s)
Redes Neurales de la Computación , Tecnología Farmacéutica/métodos , Colorimetría , Meloxicam , Microscopía/métodos , Fotograbar , Difracción de Polvo , Espectroscopía Infrarroja Corta , Espectrometría Raman , Tecnología Farmacéutica/instrumentación , Difracción de Rayos X
13.
Eur J Pharm Sci ; 129: 110-123, 2019 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-30610954

RESUMEN

The three dimensional printing (3DP) in the pharmaceutical domain constitutes an alternative, innovative approach compared to the conventional production methods. Fused deposition modelling (FDM), is a simple, cost-effective 3DP technique, however the range of pharmaceutical excipients that can be applied for this methodology is restricted. The study set to define the requirements of the FDM printability, using as technical support custom made, pharmaceutical polymer based filaments and to evaluate if these new dosage forms can live up to the current GMP/GCP quality standards. Formulation rationale was assessed in accordance to the apparatus functionality. Blends were pre-screened based on the processability under the API (carvedilol) thermogravimetric analysis determined critical limit. The technological process implied the use of FDM coupled with hot melt extrusion (HME), while printability was defined by means of thermal, rheological and mechanical measurements. From the pharmaceutical standpoint, the consistency of the in vitro dissolution kinetics was monitored 'at release' and 'in stability', while the print process impact was evaluated based on the previously determined processability potential. Results showed that FDM printability is multifactorial, with brittleness and melt viscosity as primary limitation factors. The increase in shear-thinning and flexural modulus can enable broader processability intervals, which in turn proved to be essential in limiting degradation product formation. The 3DP tablets released the API in an extended rate, however the temperature and humidity along production and storage should be carefully considered as it may affect the final product quality in time. In conclusion, HME + FDM can be considered as an alternative production methodology, with prospects of applicability in the clinical sector, however for some formulations extensive packaging development will be necessary before confirming their suitability.


Asunto(s)
Polímeros/química , Comprimidos/química , Liberación de Fármacos , Estabilidad de Medicamentos , Excipientes/química , Impresión Tridimensional , Solubilidad , Tecnología Farmacéutica/métodos , Temperatura
14.
Int J Pharm ; 569: 118593, 2019 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-31398371

RESUMEN

The objectives of this work were to develop meloxicam based amorphous solid dispersion through electrospinning technique and evaluate the effect of the polymeric matrix on the physicochemical properties of the fibers and the downstream processing ability to orodispersible dosage forms. Drug - polymer interactions formed between Eudragit E and meloxicam, confirmed through Raman and 1HNMR spectra, enabled the development of fibers from ethanol, thus allowing an increased production rate compared to PVPk30 where a DMF:THF solvent system was suitable. Microflux dissolution-permeation studies showed a significantly higher diffusion from amorphous solid dispersions compared to crystalline meloxicam. The flux through the membrane was influenced by the polymers only under basic conditions, where the precipitation of Eudragit E limited the complete resolubilization of the active ingredient. This phenomenon was not observed during large volume conventional dissolution testing. The effect of formulation on long term stability could not be highlighted as all products were stable up to 15 months, stored in closed holders at 25 °C ±â€¯2 °C and 50%RH ±â€¯10%. The increased surface area of fibers enabled tablet preparation with low pressures due to favorable bonding between particles during compression. PVPk30 formulation presented higher tabletability and compactability, as higher tensile strength compacts could be prepared. Eudragit E formulation had lower detachment and ejection stress, suggesting a lower sticking tendency during tableting. The presence of HPßCD in PVPk30 formulation offered improved morphological features of the fibers, however no significant effect was observed on dissolution, permeation or mechanical properties. Downstream processing was guided by polymer mechanical properties and solubility, thus PVPk30 fibers could be delivered in the form of orodispersible webs and conventional tablets, whereas Eudragit E fibers as orodispersible tablets.


Asunto(s)
Antiinflamatorios no Esteroideos/química , Meloxicam/química , Composición de Medicamentos/métodos , Polímeros/química , Solubilidad , Comprimidos
15.
Eur J Pharm Sci ; 114: 310-317, 2018 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-29305981

RESUMEN

In this study, brand and four generic formulations of telmisartan, an antihypertensive drug, were used in in vitro simultaneous dissolution-absorption, investigating the effect of different formulation additives on dissolution and on absorption through an artificial membrane. The in vitro test was found to be sensitive enough to show even small differences between brand and generic formulations caused by the use of different excipients. By only changing the type of filler from sorbitol to mannitol in the formulation, the flux through the membrane was reduced by approximately 10%. Changing the salt forming agent as well resulted in approximately 20% of flux reduction compared to the brand formulation. This significant difference was clearly shown in the published in vivo results as well. The use of additional lactose monohydrate in the formulation also leads to approximately 10% reduction in flux. The results show that by changing excipients, the dissolution of telmisartan was not altered significantly, but the flux through the membrane was found to be significantly changed. These results pointed out the limitations of traditional USP dissolution tests and emphasized the importance of simultaneously measuring dissolution and absorption, which allows the complex effect of formulation excipients on both processes to be measured. Moreover, the in vivo predictive power of the simultaneous dissolution-absorption test was demonstrated by comparing the in vitro fluxes to in vivo bioequivalence study results.


Asunto(s)
Bencimidazoles/química , Bencimidazoles/metabolismo , Benzoatos/química , Benzoatos/metabolismo , Liberación de Fármacos , Medicamentos Genéricos/química , Medicamentos Genéricos/metabolismo , Antihipertensivos/química , Antihipertensivos/metabolismo , Disponibilidad Biológica , Composición de Medicamentos , Liberación de Fármacos/fisiología , Membranas Artificiales , Solubilidad , Telmisartán
16.
Pharmaceutics ; 10(3)2018 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-30072667

RESUMEN

Low-dose tablet formulations were produced with excellent homogeneity based on drug-loaded electrospun fibers prepared by single-needle as well as scaled-up electrospinning (SNES and HSES). Carvedilol (CAR), a BCS II class compound, served as the model drug while poly (vinylpyrrolidone-co-vinyl acetate) (PVPVA64) was adopted as the fiber-forming polymer. Scanning electron microscopy (SEM) imaging was used to study the morphology of HSES and SNES samples. Different homogenization techniques were compared to maximize homogeneity: mixing in plastic bags and in a high-shear granulator resulting in low-shear mixing (LSM) and high-shear mixing (HSM). Drug content and homogeneity of the tablets were measured by UV-Vis spectrometry, the results revealed acceptably low-dose fluctuations especially with formulations homogenized with HSM. Sieve analysis was used on the final LSM and HSM powder mixtures in order to elucidate the observed differences between tablet homogeneity. Tablets containing drug-loaded electrospun fibers were also studied by Raman mapping demonstrating evenly distributed CAR within the corpus.

17.
Adv Healthc Mater ; 7(14): e1800315, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29920990

RESUMEN

Many factors contribute to the poor axonal regrowth and ineffective functional recovery after spinal cord injury (SCI). Biomaterials have been used for SCI repair by promoting bridge formation and reconnecting the neural tissue at the lesion site. The mechanical properties of biomaterials are critical for successful design to ensure the stable support as soon as possible when compressed by the surrounding spine and musculature. Poly(propylene fumarate) (PPF) scaffolds with high mechanical strength have been shown to provide firm spatial maintenance and to promote repair of tissue defects. A multichannel PPF scaffold is combined with collagen biomaterial to build a novel biocompatible delivery system coated with neurotrophin-3 containing an engineered collagen-binding domain (CBD-NT3). The parallel-aligned multichannel structure of PPF scaffolds guide the direction of neural tissue regeneration across the lesion site and promote reestablishment of bridge connectivity. The combinatorial treatment consisting of PPF and collagen loaded with CBD-NT3 improves the inhibitory microenvironment, facilitates axonal and neuronal regeneration, survival of various types of functional neurons and remyelination and synapse formation of regenerated axons following SCI. This novel treatment strategy for SCI repair effectively promotes neural tissue regeneration after transected spinal injury by providing a regrowth-supportive microenvironment and eventually induces functional improvement.


Asunto(s)
Fumaratos/química , Factores de Crecimiento Nervioso/química , Regeneración Nerviosa/fisiología , Polipropilenos/química , Traumatismos de la Médula Espinal/terapia , Andamios del Tejido/química , Animales , Ratas , Ingeniería de Tejidos
18.
J Pharm Sci ; 106(6): 1634-1643, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28257818

RESUMEN

Novel, high-yield alternating current electrospinning (ACES) and direct current electrospinning methods were investigated to prepare high-quality hydroxypropylmethylcellulose acetate succinate (HPMCAS) fibers for the dissolution enhancement of poorly soluble spironolactone. Although HPMCAS is of great pharmaceutical importance as a carrier of marketed solid dispersion-based products, it was found to be unprocessable using electrospinning. Addition of small amounts of polyethylene oxide as aid polymer provided smooth fibers with direct current electrospinning but strongly beaded products with ACES. Solution characteristics were thus modified by introducing further excipients. In the presence of sodium dodecyl sulfate, high-quality, HPMCAS-based fibers were obtained even at higher throughput rates of ACES owing to the change in conductivity (rather than surface tension). Replacement of sodium dodecyl sulfate with non-surface-active salts (calcium chloride and ammonium acetate) maintained the fine quality of nanofibers, confirming the importance of conductivity in ACES process. The HPMCAS-based fibers contained spironolactone in an amorphous form according to differential scanning calorimetry and X-ray powder diffraction. In vitro dissolution tests revealed fast drug release rates depending on the salt used to adjust conductivity. The presented results signify that ACES can be a prospective process for high-scale production of fibrous solid dispersions in which conductivity of solution has a fundamental role.


Asunto(s)
Portadores de Fármacos/química , Excipientes/química , Metilcelulosa/análogos & derivados , Nanofibras/química , Liberación de Fármacos , Metilcelulosa/química , Nanofibras/ultraestructura , Polietilenglicoles/química , Dodecil Sulfato de Sodio/química , Solubilidad , Espironolactona/administración & dosificación , Espironolactona/química
19.
Mater Sci Eng C Mater Biol Appl ; 72: 625-630, 2017 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-28024631

RESUMEN

Therapeutic stem cell transplantation bears the promise of new directions in organ and tissue replacement, but a number of its difficulties and perils are also well known. Our goal was to develop a method of transplantation by which the transplanted cells remain confined to the transplantation site and induce favorable processes. With the help of mask-projection excimer laser stereolithography, 3D hybrid nanoscaffolds were fabricated from biodegradable, photocurable PPF:DEF resin with incorporated gold nanoparticles (Au NPs). The scaffolds were tested in vitro and in vivo in order to find out about their biocompatibility and fitness for our purposes. In vitro, macrophages and mouse autologous adipose stem cells (ASCs) were seeded over the hybrid scaffolds and non-hybrid (with Au NPs) scaffolds for 4days. The hybrid nanocomposite greater stem cell dispension and stem cell adhesion than PPF scaffolds without Au NPs, but such a difference was not seen in the case of macrophages. In vivo, stem cells, scaffoldings and scaffoldings covered in stem cells were transplanted under the back skin of mice. After 14days, blood samples were taken and the affected skin area was excised. Cytokine and chemokine profiling did not indicate elevated immunomediators in the sera of experimental animals. Interestingly, the autologous-stem-cell-seeded hybrid nanocomposite scaffold induced muscle tissue regeneration after experimental wound generation in vivo. We could not observe such stem cell-induced tissue regeneration when no scaffolding was used. We conclude that PPF:DEF resin nanoscaffolds with incorporated gold nanoparticles offer a safe and efficient alternative for the enhancement of local tissue remodeling. The results also support the idea that adipose derived stem cells are an optimal cell type for the purposes of regenerative musculoskeletal tissue engineering.


Asunto(s)
Materiales Biocompatibles/química , Oro/química , Nanopartículas del Metal/química , Polímeros/química , Andamios del Tejido/química , Tejido Adiposo/citología , Animales , Materiales Biocompatibles/metabolismo , Materiales Biocompatibles/farmacología , Adhesión Celular/efectos de los fármacos , Células Cultivadas , Quimiocinas/metabolismo , Citocinas/metabolismo , Femenino , Masculino , Ratones , Ratones Endogámicos BALB C , Microscopía Confocal , Piel/patología , Trasplante de Células Madre , Células Madre/citología , Células Madre/efectos de los fármacos , Células Madre/metabolismo , Ingeniería de Tejidos
20.
Int J Pharm ; 505(1-2): 159-66, 2016 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-26997426

RESUMEN

Alternating current electrospinning (ACES) capable to reach multiple times higher specific productivities than widely used direct current electrospinning (DCES) was investigated and compared with DCES to prepare drug-loaded formulations based on one of the most widespread polymeric matrix used for commercialized pharmaceutical solid dispersions, hydroxypropylmethylcellulose 2910 (HPMC). In order to improve the insufficient spinnability of HPMC (both with ACES and DCES) polyethylene oxide (PEO) as secondary polymer with intense ACES activity was introduced into the electrospinning solution. Different grades of this polymer used at as low concentrations in the fibers as 0.1% or less enabled the production of high quality HPMC-based fibrous mats without altering its physicochemical properties remarkably. Increasing concentrations of higher molecular weight PEOs led to the thickening of fibers from submicronic diameters to several microns of thickness. ACES fibers loaded with the poorly water-soluble model drug spironolactone were several times thinner than drug-loaded fibers prepared with DCES in spite of the higher feeding rates applied. The amorphous HPMC-based fibers with large surface area enhanced the dissolution of spironolactone significantly, the presence of small amounts of PEO did not affect the dissolution rate. The presented results confirm the diverse applicability of ACES, a novel technique to prepare fibrous drug delivery systems.


Asunto(s)
Sistemas de Liberación de Medicamentos , Derivados de la Hipromelosa/química , Polietilenglicoles/química , Espironolactona/administración & dosificación , Química Farmacéutica/métodos , Portadores de Fármacos/química , Composición de Medicamentos/métodos , Electricidad , Peso Molecular , Solubilidad , Espironolactona/química
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