Microparticles are small circulating vesicles originating from circulatory system and vascular wall cells released during their activation or damage. They possess different roles in regulation of endothelial function, inflammation, thrombosis, angiogenesis, and in general, cellular stress. Microparticles are the subject of intensive research in pulmonary hypertension, atherosclerotic disease, and heart failure. Another recently emerging role is the evaluation of the status of vasculature in end-stage heart failure patients treated with implantable ventricular assist devices. In patients implanted as destination therapy, assessment of the long-term effect of currently used continuous-flow left ventricular assist devices (LVADs) on vasculature might be of critical importance. However, unique continuous flow pattern generated by LVADs makes it difficult to assess reliably the vascular function with most currently used methods, based mainly on ultrasound detection of changes of arterial dilatation during pulsatile flow. In this respect, the measurement of circulating microparticles as a marker of vascular status may help to elucidate both short- and long-term effects of LVADs on the vascular system. Because data regarding this topic are very limited, this review is focused on the advantages and caveats of the circulating microparticles as markers of vascular function in patients on continuous-flow LVADs.
- MeSH
- Biomarkers blood MeSH
- Humans MeSH
- Cell-Derived Microparticles * MeSH
- Vascular Diseases diagnosis etiology MeSH
- Heart-Assist Devices adverse effects MeSH
- Heart Failure therapy MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Formulace mikročástic složených ze směsi nosičů představuje inovativní přístup pro podání léčiv do plic ve formě suchého prášku. Použité nosiče mohou významně ovlivnit výsledné vlastnosti mikročástic, jako je velikost, tvar, povrch, hygroskopicita či agregace, a tím zlepšit aerosolizaci léčiv po jejich inhalaci. Zmíněné vlastnosti jsou klíčové pro efektivní pulmonální terapii. Kombinací nosičů povahy sacharidů a gelujících látek je výhodné pro řízené uvolňování léčiva. Cílem experimentální práce bylo sprejovým sušením připravit a následně zhodnotit několik šarží mikročástic složených z nosičů na bázi cukrů (manitol, maltodextrin, dextran) a gelujících sacharidů (chitosan, chondroitin-sulfát) a vybrat vhodnou kombinaci pro navazující experimentální práce zaměřené na inkorporaci léčiva do mikročásticové matrice. Nejvhodnější parametry vykazovaly šarže, jejichž aerodynamický průměr se blížil 5 μm, a to částice připravené z kombinace manitolu a dextranu, chitosanu a chondroitinu nebo maltodextrinu a chondoitinu. U těchto šarží byla také naměřena nejvyšší hodnota frakce jemných částic (> 43 %). Z pohledu zpracovatelnosti je vhodná šarže se zastoupením maltodextrinu a chondroitinu vzhledem k nižší viskozitě vstupní disperze a pravidelnějšímu tvaru finálních mikročástic.
The formulation of microparticles composed of a mixture of carriers represents an innovative approach for lung drug delivery of dry powder. The carriers used can significantly influence the properties of the microparticles, such as size, shape, surface area, hygroscopicity, or aggregation, thus improving the aerosolization of the drugs after inhalation. The properties mentioned above are crucial for effective pulmonary therapy. The combination of carriers of a carbohydrate nature and gelling agents is advantageous for controlled drug release. The experimental work aimed to prepare by spray drying and subsequently evaluate ten batches of microparticles composed of sugar-based carriers (mannitol, maltodextrin, dextran) and gelling polymers (chitosan, chondroitin sulfate) and to select a suitable combination for follow-up experimental work aimed at drug incorporation into the microparticle matrix. The most suitable parameters were exhibited by batches whose aerodynamic diameter was close to 5 μm, particles prepared from a combination of mannitol and dextran, chitosan and chondroitin, or maltodextrin and chondroitin. These batches also showed the highest fine particle fraction value (> 43%). From a processability point of view, the batch with maltodextrin and chondroitin is preferable due to the lower viscosity of the dispersion and the more regular shape of the final microparticles.
- MeSH
- Administration, Inhalation MeSH
- Pharmaceutical Research MeSH
- Humans MeSH
- Microplastics MeSH
- Drug Carriers * MeSH
- Spray Drying MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
Microparticles prepared from biodegradable and biocompatible polymers are a modern dosage form which has a high potential to fulfil requirements for controlled drug release. The solvent evaporation method is one of the most common methods used for preparation of microparticles. This method is cheap, fast and simple, especially in laboratory conditions. Its modifications allow to encapsulate many hydrophilic and hydrophobic pharmaceuticals including peptides, proteins and cytostatics. The method is based on emulsification of the polymer and drug in the continuous phase. The process then involves evaporation of the continuous phase and formation of a solid polymer matrix in which the drug is entrapped. The solid microparticles are collected and dried. The properties of the microparticles can be influenced by modification of the method, process variables or by formulation. Optimization of the process parameters is envisaged.
- MeSH
- Patient Compliance MeSH
- Technology, Pharmaceutical trends MeSH
- Hydrophobic and Hydrophilic Interactions MeSH
- Lactic Acid * MeSH
- Polyglycolic Acid * MeSH
- Dosage Forms * MeSH
- Drug Delivery Systems * MeSH
- Humans MeSH
- Nanocapsules MeSH
- Drug Carriers * MeSH
- Polymers MeSH
- Surface Properties MeSH
- Solvents MeSH
- Therapeutic Equivalency MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
Za mikropartikule (MP) můžeme považovat částice s velikostí 0,05– 1 mm. Jejich složení je značně variabilní dle jejich původu. Vždy však nesou na svém povrchu glykoproteiny exprimované taktéž na povrchu buněk. Této vlastnosti se také využívá k jejich detekci pomocí monoklonálních protilátek. MP se uvolňují jako fragmenty z plazmatické membrány prakticky všech typů eukaryotických buněk po jejich stimulaci nebo v rámci jejich apoptózy. MP se mohou tvořit také při procesu narušení buněčné tkáně. Vznik MP takto může reprezentovat širokou odpověď podněty typu buněčného stimulu nebo stresu. V patogenezi zánětu patří mezi klíčové kroky poškození endotelu a uvolnění membrány mikročástic. Metody detekce MP vychází jednak ze snahy stanovit jejich absolutní počet a jednak stanovit jejich trombogenní potenciál. Pro stanovení počtu MP lze s úspěchem využít průtokovou cytometrii, kdy bylo v poslední době popsáno mnoho metod využívajících široké spektrum monoklonálních protilátek. V současné době se využívají zejména stanovení trombocytárních MP pomocí detekce exprese CD41 znaku a endoteliální MP pomocí CD144 znaku. ELISA metodiky naopak slouží pro stanovení trombogenního potenciálu MP pomocí detekce exprese P- selektinu. Specifi ckou metodou se jeví použití trombin generačního testu v kombinaci s ultrafi ltrací pro stanovení trombogenního potenciálu MP. Patologie spojené s MP vychází zejména z poznání jejich patofyziologických vlastností. Trombogenní potenciál je benefi tem u trombocytopenií, kde vysoké hladiny MP jsou detekovány u pacientů bez krvácivých komplikací. Tato vlastnost však může být příčinou trombotických komplikací. Naopak negativní vliv mohou mít MP u infarktu myokardu, zánětlivých procesů nebo roztroušené sklerózy.
Microparticles (MPs) are particles sized 0.05– 1 mm. Their composition varies considerably depending on their origin. On their surface, however, glycoproteins are always found, that are also expressed on the cell surface. This characteristic is used for their detection using monoclonal antibodies. MPs are released as fragments from the plasma membrane of practically all types of eukaryotic cells, either after their stimulation or during apoptosis. MPs may also be formed in the process of cellular tissue damage. Thus, MP formation may represent a wide response to common stimuli in processes such as cellular stress. Endothelial damage and membrane disruption are the key steps in the pathogenesis of infl ammation. Methods for detecting MPs result from attempts to determine both their absolute count and their thrombogenic potential. To measure the count of MPs, fl ow cytometry may be used with success. Recently, numerous methods using a broad spectrum of monoclonal antibodies have been described. At present, platelet MPs are determined by detecting expression of CD41 and endothelial MPs by expression of CD144. By contrast, ELISA methods are used to evaluate the thrombogenic potential of MPs by detecting expression of P- selectin. A specifi c method is the thrombin generation assay combined with ultrafi ltration to assess the thrombogenic potential of MPs. Understanding the role of MPs in the pathology of numerous diseases is primarily based on the knowledge of their pathophysiological properties. The thrombogenic potential is benefi cial in thrombocytopenia, with high levels of MPs being detected in patients without bleeding complications. However, this feature may cause thrombotic complications. On the other hand, MPs may play a negative role in myocardial infarction, infl ammatory processes or multiple sclerosis.
- Keywords
- generace trombinu, trombofilní riziko,
- MeSH
- Anticoagulants blood therapeutic use MeSH
- Biomarkers blood MeSH
- Endothelium, Vascular enzymology physiopathology pathology MeSH
- Enzyme-Linked Immunosorbent Assay methods utilization MeSH
- Financing, Organized MeSH
- Clinical Laboratory Techniques MeSH
- Humans MeSH
- Membrane Glycoproteins isolation & purification blood MeSH
- Cell-Derived Microparticles classification MeSH
- P-Selectin isolation & purification blood MeSH
- Flow Cytometry methods utilization MeSH
- Selectins isolation & purification blood MeSH
- Thrombin isolation & purification classification MeSH
- Thrombosis enzymology etiology blood MeSH
- Inflammation enzymology etiology blood MeSH
- Check Tag
- Humans MeSH
Mikročástice na bázi biodegradovatelného syntetického kopolymeru kyseliny mléčné a kyseliny glykolové (PLGA) byly úspěšně připraveny metodou odpařování rozpouštědla. Modelovým léčivem pro enkapsulaci byl zvolen ibuprofen. Pro přípravu každého vzorku byly použity odlišné formulační a procesní parametry různě ovlivňující výsledné mikročástice. Během odpařování rozpouštědla byl konkrétně sledován vliv metody emulgování (přímé emulgování či přímé emulgování za využití přístroje ULTRA-TURRAX nebo NE-1000 dávkovače), objemu vodné fáze (200, 800 ml) a rychlosti míchání tohoto emulzního systému (600, 1000 ot/min) na charakteristické vlastnosti mikročástic, jako je enkapsulační účinnost, drug loading a morfologie částic. Vzniklé mikročástice byly hodnoceny pomocí optické mikroskopie, případně laserové difrakce, a byla také provedena disoluční zkouška. Nejpříznivější výsledky byly pozorovány u vzorku připraveného přímým emulgováním s 800 ml vodné fáze o rychlosti míchání 600 ot/min. Vzorek připravený s pre-emulzifikačním krokem na homogenizátoru se zase vyznačoval slibným zmenšením velikosti částic. Postupná emulzifikace byla naopak shledána jako nepoužitelná kvůli velkým ztrátám.
Microparticles based on biodegradable synthetic lactic acid and glycolic acid copolymer (PLGA) were successfully prepared by the solvent evaporation method. Ibuprofen was chosen as the model drug. Various formulation and process parameters have been used to prepare each sample with emphasis on size reduction. The effect of the emulsification method (direct emulsification or emulsification using an ULTRA-TURRAX or a NE-1000 dispenser), the volume of the aqueous phase (200, 800 ml) and the stirring speed of the emulsion system (600, 1000 rpm) on the characteristic properties of microparticles, such as encapsulation efficiency, drug loading and particle morphology, was observed. The resulting microparticles were evaluated by optical microscopy or laser diffraction and the dissolution test was performed. It was found that the sample prepared by direct emulsification with 800 ml of an aqueous phase at 600 rpm provided the most favorable results, meanwhile the emulsification pre-step using a homogenizer caused promising particle size reduction. Gradual emulsification was evaluated as inapplicable due to great losses.
PURPOSE OF THE STUDY Articular cartilage defects arise due to injury or osteochondral disease such as osteonecrosis or osteochondritis dissecans. In adult patients cartilage has minimal ability to repair itself and the lesions develop into degenerative arthritis. Overcoming the low regenerative capacity of the cartilage cells and the Hayflick limit poses a challenge for the therapy of osteochondral defects. Composite scaffolds with appropriate biomechanical properties combined with a suitable blend of proliferation and differentiation factors could be a solution. The aim of this in vitro study was to develop a novel functionalised hydrogel with an integrated drug delivery system stimulating articular cartilage regeneration. MATERIAL AND METHODS Injectable collagen/ hyaluronic acid/fibrin composite hydrogel was mixed with nanofibre-based microparticles. These were loaded with ascorbic acid and dexamethasone. In addition, the effect of thrombocyte-rich solution (TRS) was studied. The gels seeded with mesenchymal stem cells (MSCs) were cultivated for 14 days. The viability, proliferation and morphology of the cells were evaluated using molecular and microscopic methods. Scaffold degradation was also assessed. RESULTS The cultivation study showed that MSCs remained viable in all experimental groups, which indicated good biocompatibility of the gel. However, the number of cells in the groups enriched with microparticles was lower than in the other groups. On the other hand, confocal microscopy showed higher cell viability and rounded morphology of the cells, which can be associated with chodrogenic differentiation. The scaffolds containing microparticles showed significantly higher stability during the 14-day experiment. DISCUSSION Our results suggest that the addition of microparticles to the scaffold improved cell differentiation into the chondrogenic lineage, resulting in a lower proliferation rate. Cell viability was better in the groups enriched with microparticles that served as an efficient drug delivery system. In addition, the presence of microparticles slowed down gel degradation which can help achieve sufficient stability of the system for the time frame required for cartilage regeneration. CONCLUSIONS The novel approach described here produced an efficient system where microparticles served as a drug delivery system and stabilised the gel for prolonged periods of time. These characteristics play an important role in the development of scaffolds for cartilage regeneration. In the future the results of these in vitro experiments will be verified in an in vivo study.
- MeSH
- Injections, Intra-Articular MeSH
- Cartilage, Articular * pathology drug effects MeSH
- Drug Delivery Systems * methods MeSH
- Multipotent Stem Cells * physiology metabolism MeSH
- Nanofibers therapeutic use MeSH
- Drug Carriers * MeSH
- Osteoarthritis therapy MeSH
- Hydrogel, Polyethylene Glycol Dimethacrylate therapeutic use MeSH
- Drug Compounding methods MeSH
- Cell Proliferation MeSH
- Guided Tissue Regeneration * methods MeSH
- In Vitro Techniques MeSH
- Blood Platelets physiology metabolism MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
In this paper, we demonstrate the effectiveness of a new 3D printed magnet holder that enables capture of magnetic microparticles in commercially available capillary electrophoresis equipment with a liquid or air based coolant system. The design as well as the method to capture magnetic microparticles inside the capillary are discussed. This setup was tested at temperature and pH values suitable for performing enzymatic reactions. To demonstrate its applicability in CE- immobilized microenzyme reactors (IMER) development, human flavin-containing monooxygenase 3 and bovine serum albumin were immobilized on amino functionalized magnetic microparticles using glutaraldehyde. These microparticles were subsequently used to perform in-line capillary electrophoresis with clozapine as a model substrate. This setup could be used further to establish CE-IMERs of other drug metabolic enzymes in a commercially available liquid based capillary coolant system. The CE-IMER setup was successful, although a subsequent decrease in enzyme activity was observed on repeated runs.
- MeSH
- Amines chemistry MeSH
- Equipment Design instrumentation MeSH
- Electrophoresis, Capillary instrumentation MeSH
- Enzymes, Immobilized chemistry MeSH
- Glutaral chemistry MeSH
- Clozapine chemistry MeSH
- Humans MeSH
- Magnetic Fields MeSH
- Magnets chemistry MeSH
- Microspheres * MeSH
- NADP chemistry MeSH
- Silicon Dioxide chemistry MeSH
- Oxygenases chemistry MeSH
- Surface Properties MeSH
- Serum Albumin, Bovine chemistry MeSH
- Enzyme Stability MeSH
- Temperature MeSH
- Particle Size MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Iron oxide based particles functionalized by bioactive molecules have been utilized extensively in biotechnology and biomedicine. Despite their already proven advantages, instability under changing reaction conditions, non-specific sorption of biomolecules on the particles' surfaces, and iron oxide leakage from the naked particles can greatly limit their application. As confirmed many times, surface treatment with an appropriate stabilizer helps to minimize these disadvantages. In this work, we describe enhanced post-synthetic surface modification of superparamagnetic microparticles varying in materials and size using hyaluronic acid (HA) in various chain lengths. Scanning electron microscopy, atomic force microscopy, phase analysis light scattering and laser diffraction are the methods used for characterization of HA-coated particles. The zeta potential and thickness of HA-layer of HA-coated Dynabeads M270 Amine were -50 mV and 85 nm, respectively, and of HA-coated p(GMA-MOEAA)-NH2 were -38 mV and 140 nm, respectively. The electrochemical analysis confirmed the zero leakage of magnetic material and no reactivity of particles with hydrogen peroxide. The rate of non-specific sorption of bovine serum albumin was reduced up to 50% of the naked ones. The coating efficiency and suitability of biopolymer-based microparticles for magnetically active microfluidic devices were confirmed.
- MeSH
- Chemical Phenomena MeSH
- Hyaluronic Acid chemistry MeSH
- Magnetics * MeSH
- Microfluidics methods MeSH
- Microscopy, Electron, Scanning MeSH
- Surface Properties MeSH
- Serum Albumin, Bovine MeSH
- Particle Size MeSH
- Ferric Compounds chemistry MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
For biodegradable porous scaffolds to have a potential application in cartilage regeneration, they should enable cell growth and differentiation and should have adequate mechanical properties. In this study, our aim was to prepare biocompatible scaffolds with improved biomechanical properties. To this end, we have developed foam scaffolds from poly-epsilon-caprolactone (PCL) with incorporated chitosan microparticles. The scaffolds were prepared by a salt leaching technique from either 10 or 15 wt% PCL solutions containing 0, 10 and 20 wt% chitosan microparticles, where the same amount and size of NaCl was used as a porogen in all the cases. PCL scaffolds without and with low amounts of chitosan (0 and 10 wt% chitosan) showed higher DNA content than scaffolds with high amounts of chitosan during a 22-day experiment. 10 wt% PCL with 10 and 20 wt% chitosan showed significantly increased viscoelastic properties compared to 15 wt% PCL scaffolds with 0 and 10 wt% chitosan. Thus, 10 wt% PCL scaffolds with 0 wt% and 10 wt% chitosan are potential scaffolds for cartilage regeneration.
- MeSH
- Biocompatible Materials administration & dosage chemistry MeSH
- Cartilage cytology physiology MeSH
- Cells, Cultured MeSH
- Humans MeSH
- Microspheres * MeSH
- Polyesters administration & dosage chemistry MeSH
- Cell Proliferation drug effects physiology MeSH
- Guided Tissue Regeneration methods MeSH
- Tissue Scaffolds * MeSH
- Cell Survival drug effects physiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Inhalační podání suchých práškových částic je využívanou aplikační cestou pro dosažení lokálního i systémového působení léčiv. U plicních onemocnění je žádoucí depozice léčiv v místě účinku. Pro efektivní léčbu jsou tak zásadní parametry inhalovaných částic, a to především jejich velikost, tvar nebo aerosolizační parametry. Vhodných parametrů je možné dosáhnout volbou metody přípravy nebo pomocných látek (nosičů, porogenů nebo aerosolizačních činidel). Cílem experimentu byla příprava jedenácti šarží práškových směsí sprejovým sušením, které se lišily použitým nosičem, množstvím leucinu či porogenu. Cílem bylo optimalizovat složení pro navázání léčiva s ohledem na požadavky pro plicní podání. Připravené částice byly zhodnoceny z hlediska morfologie, tokových vlastností, pórovitosti, geometrického i aerodynamického průměru. Bylo zjištěno, že se zvyšující se koncentrací leucinu se sypná hustota částic snižovala a zároveň rostla hodnota FPF. Stejně tak docházelo i ke snižování MMAD. Jako vhodná se jevila šarže obsahující 15 % leucinu. Při stanovení optimální koncentrace porogenu (hydrogenuhličitan amonný) u manitolových částic dosahovala nejlepších výsledků šarže s jeho 1% zastoupením, vzhledem k vyhovující velikosti částic oproti ostatním šaržím (MMAD 5,92 ± 1,32 μm), vhodné pórovitosti a obecně přijatelné morfologii částic. Za účelem formulace částic s navázaným léčivem by tedy bylo vhodné snížit aerodynamický průměr částic např. úpravou procesních parametrů sprejového sušení.
Inhalation administration of dry powder particles is a common application route to achieve local and systemic drug effects. For pulmonary diseases, the deposition of drugs at the site of action is desirable. Thus, the parameters of the inhaled particles, especially their size, shape, or aerosolization, are essential for effective treatment. Suitable parameters can be achieved by choice of preparation method or excipients (carriers, porogens, or aerosolizing agents). This experiment aimed to prepare 11 batches of powder mixtures by spray drying, which differed in the carrier used and the amount of leucine or porogen. The aim was to optimize the formulation for drug binding concerning the requirements for pulmonary administration. The prepared particles were evaluated in terms of morphology, flow properties, porosity, and geometric and aerodynamic diameter. It was found that with increasing concentration of leucine, the bulk density of the particles decreased while the FPF value increased. Similarly, there was a decrease in MMAD. The batch containing 15% leucine was the most suitable. In determining the optimum porogen concentration for mannitol particles, the batch with its 1% gave the best results due to its adequate particle size compared to the other batches (MMAD 5.92 ± 1.32 μm), suitable porosity, and particle morphology. Thus, to formulate drug-loaded particles, it would be advisable to reduce the aerodynamic diameter of the particles, e.g., by spray drying process parameters.
