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1.
Medicina (Kaunas) ; 59(2)2023 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-36837481

RESUMEN

Background and Objectives: This single-center retrospective study was conducted to describe clinical characteristics and the disease course of patients with interstitial lung diseases (ILD). Materials and Methods: The study included adult patients with fibrosing ILD (IPF, non-IPF fibrosing ILD (F-ILD), and non-IPF progressive pulmonary fibrosis (PPF)) treated between 2014 and 2017. Patients were followed annually from the first visit until the end of the study period in 2019. Data were collected from the Turku University Hospital data lake and analyzed using descriptive statistics. Results: 591 patients formed the patient cohort: 110 had IPF, 194 F-ILD, 142 PPF, and the remaining 145 patients were uncertain, F-ILD-U, whose disease progression nature could not be confirmed by FVC measurements. There were more males in each patient group and median age of the groups was similar, although there were younger patients in the PPF, F-ILD, and F-ILD-U groups. PPF patients had more UIP pattern than F-ILD patients. Exposure-related ILDs were clearly the most found ILD diagnoses for both PPF and F-ILD, followed by unclassifiable IIP. Baseline FVC % predicted reduction in every group was moderate. Half of the patients in each group had comorbidities, and the most common were cardiovascular diseases, diabetes, sleep apnea, and chronic lower respiratory diseases; F-ILD-U patients had malignant diseases as well. IPF patients had less medications than the other groups. Glucocorticoids were the most used medication in all patient groups. More PPF and F-ILD patients remained in the follow-up than IPF and F-ILD-U patients. Similarly, mortality of F-ILD-U was the highest, followed by IPF. Evolvement of lung function, oxygen use, and number of acute hospitalizations were similar for IPF and PPF patients whereas the corresponding results were always better for F-ILD patients. Conclusions: The disease course of IPF and PPF was similar, and PPF patient amount exceeded the amount of IPF patients.


Asunto(s)
Enfermedades Pulmonares Intersticiales , Fibrosis Pulmonar , Masculino , Adulto , Humanos , Estudios Retrospectivos , Enfermedades Pulmonares Intersticiales/diagnóstico , Fibrosis , Progresión de la Enfermedad
2.
Medicina (Kaunas) ; 55(11)2019 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-31744064

RESUMEN

Background and Objectives: Evaluation of data from electronic health care records could help in guiding towards more rational drug treatments. This single center study evaluated clinical characteristics that could be associated with disease progression. Methods: This was a real world data (RWD) study using existing data from the registries of a university hospital. Patients had lung adenocarcinoma and they had received 1st line treatment. Treatment patterns and survival parameters were characterized and clinical characteristics of the patients were evaluated together with their association with disease progression. Results: 80 stage III/IV patients fulfilling inclusion criteria were identified. Mean age was 62 years and 61% were men. In total, 65% were current smokers and 82% had performance status (ECOG) 0/1. Median progression free survival (mPFS) and median overall survival (mOS) for stage III and IV patients were 8.5 and 5.4 months, and 21.9 and 8.6 months, respectively. The study found that 69% of patients progressed within 9 months from the start of the 1st line treatment. Poor performance status (ECOG 3), male gender, and smoking suggested faster disease progression. Most had received cis/carboplatin-based treatment in the 1st line. Cisplatin regimens were associated with more complete responses and better PFS and OS than the carboplatin ones. Conclusions: By combining algorithmic and manual validation of electronic health care records, clinically valid characteristics and outcomes could be evaluated and presented. This approach forms a basis for tools such as quality registries that can guide treatment decisions.


Asunto(s)
Adenocarcinoma del Pulmón/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/normas , Quimioterapia/normas , Resultado del Tratamiento , Adenocarcinoma del Pulmón/complicaciones , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Quimioterapia/métodos , Quimioterapia/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sistema de Registros/estadística & datos numéricos , Estudios Retrospectivos
3.
Sci Rep ; 6: 21417, 2016 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-26892874

RESUMEN

Nanoparticles are useful tools in oncology because of their capacity to passively accumulate in tumors in particular via the enhanced permeability and retention (EPR) effect. However, the importance and reliability of this effect remains controversial and quite often unpredictable. In this preclinical study, we used optical imaging to detect the accumulation of three types of fluorescent nanoparticles in eight different subcutaneous and orthotopic tumor models, and dynamic contrast-enhanced and vessel size index Magnetic Resonance Imaging (MRI) to measure the functional parameters of these tumors. The results demonstrate that the permeability and blood volume fraction determined by MRI are useful parameters for predicting the capacity of a tumor to accumulate nanoparticles. Translated to a clinical situation, this strategy could help anticipate the EPR effect of a particular tumor and thus its accessibility to nanomedicines.


Asunto(s)
Imagen por Resonancia Magnética , Nanopartículas/química , Neoplasias/diagnóstico , Animales , Línea Celular Tumoral , Medios de Contraste , Modelos Animales de Enfermedad , Xenoinjertos , Humanos , Lípidos/química , Imagen por Resonancia Magnética/métodos , Ratones , Nanopartículas/administración & dosificación , Neoplasias/metabolismo , Tamaño de la Partícula , Permeabilidad
4.
Mol Pharm ; 11(9): 3133-44, 2014 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-25098740

RESUMEN

DiI and DiD, two fluorophores able to interact by FRET (Förster resonance energy transfer), were coencapsulated in the core of lipid nanocapsules (LNCs) and nanoemulsions (LNEs), lipophilic reservoirs for the delivery of drugs. The ability of FRET imaging to provide information on the kinetics of dissociation of the nanoparticles in the presence of bovine serum albumin (BSA) or whole serum, or after incubation with cancer cells, and after systemic administration in tumor-bearing mice, was studied. Both microscopic and macroscopic imaging was performed to determine the behavior of the nanostructures in a biological environment. When 2 mg/mL FRET LNEs or LNCs were dispersed in buffer, in the presence of unloaded nanoparticles, BSA, or in whole serum, the presence of serum was the most active in destroying the particles. This occurred immediately with a diminution of 20% of FRET, then slowly, ending up with still 30% intact nanoparticles at 24 h. LNCs were internalized rapidly in cultured cells with the FRET signal decreasing within the first minutes of incubation, and then a plateau was reached and LNCs remained intact during 3 h. In contrast, LNEs were poorly internalized and were rapidly dissociated after internalization. Following their iv injection, LNCs appeared very stable in subcutaneous tumors implanted in mice. Intact particles were found using microscopic FRET determination on tumor sections 24 h after injection, that correlated well with the 8% calculated noninvasively on live animals. FRET investigations showed the potential to determine valid and reliable information about in vitro and in vivo behavior of nanoparticles.


Asunto(s)
Transferencia Resonante de Energía de Fluorescencia/métodos , Lípidos/química , Nanopartículas/química , Animales , Línea Celular , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos/métodos , Femenino , Colorantes Fluorescentes/química , Células HEK293 , Humanos , Técnicas In Vitro/métodos , Cinética , Ratones , Ratones Desnudos , Nanocápsulas/química , Tamaño de la Partícula , Albúmina Sérica Bovina/química , Solubilidad
5.
Eur J Pharm Biopharm ; 87(1): 152-9, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24361535

RESUMEN

Combining targeting to therapy remains a major challenge in cancer treatment. To address this subject, the surface of lipid nanocapsules (LNC) was modified by grafting cRGD peptides, which are known to be recognised by αvß3 integrins expressed by tumour endothelium and cancer cells. Applicability of this LNC-cRGD in tumour targeting was first assessed in vitro by the use of U87MG glioma cells. Biodistribution and tumour accumulation of radiolabelled LNC-cRGD in vivo were then evaluated in mice bearing the same subcutaneous xenograft. Flow cytometry and confocal microscopy results revealed that the cRGD grafting improved binding and internalisation compared to negative control LNC-cRAD and blank LNC. The peptide-grafted LNC remained in the blood circulation up to 3h with reduced capture by the RES organs. Tumour accumulation of LNC-cRGD with respect to LNC-cRAD was significantly higher at 1-3h. These results show that cRGD grafted to LNC has created a promising tumour-targetable nanocarrier that could be used in cancer treatment.


Asunto(s)
Antineoplásicos/administración & dosificación , Portadores de Fármacos/química , Lípidos/química , Nanocápsulas/química , Péptidos Cíclicos/química , Animales , Portadores de Fármacos/farmacocinética , Femenino , Humanos , Lípidos/farmacocinética , Ratones Desnudos , Terapia Molecular Dirigida , Péptidos Cíclicos/farmacocinética , Distribución Tisular , Ensayos Antitumor por Modelo de Xenoinjerto
6.
Int J Pharm ; 453(2): 594-600, 2013 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-23747436

RESUMEN

In vivo biodistribution of nanoparticles depends on several physicochemical parameters such as size. After intravenous injection of 25, 50 and 100 nm lipid nanocapsules (LNC) in nude mice bearing HEK293(ß3) tumour xenografts, biodistribution was evaluated by γ-scintigraphy and by γ-counting. The small LNC 25 nm disappeared faster than the larger LNC 50 and 100 nm from the blood circulation due to faster elimination and wider tissue distribution. At 24h, biodistribution profiles of all these LNC were similar. Low LNC quantities were found in this weak EPR (enhanced permeability and retention) tumour regardless the particle size. Co-injected 50 nm fluorescent DiD-LNC and (99m)Tc-LNC allowed direct comparison of biodistribution as evaluated by the two methods. Optical imaging underestimated LNC quantity especially in dark-colored organs that were observed to capture extensive quantities of the particles by γ-counting (i.e. liver, spleen, and kidney).


Asunto(s)
Lípidos/farmacocinética , Nanocápsulas , Animales , Femenino , Células HEK293 , Humanos , Lípidos/administración & dosificación , Lípidos/química , Ratones , Ratones Desnudos , Nanocápsulas/administración & dosificación , Nanocápsulas/química , Imagen Óptica/métodos , Tamaño de la Partícula , Cintigrafía , Conteo por Cintilación , Tecnecio , Distribución Tisular
7.
Acta Biomater ; 9(5): 6686-93, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23395817

RESUMEN

Attaching polysaccharides to the surface of nanoparticles offers the possibility of modifying the physicochemical and biological properties of the core particles. The surface of lipid nanocapsules (LNCs) was modified by post-insertion of amphiphilic lipochitosan (LC) or lipodextran (LD). Modelling of these LNCs by the drop tensiometer technique revealed that the positively charged LC made the LNC surface more rigid, whereas the neutral, higher M(W) LD had no effect on the surface elasticity. Both LNC-LC and LNC-LD activated the complement system more than the blank LNC, thus suggesting increased capture by the mononuclear phagocyte system. In vitro, the positively charged LNC-LC were more efficiently bound by the model HEK293(ß3) cells compared to LNC and LNC-LD. Finally, it was observed that neither LC nor LD changed the in vivo biodistribution properties of LNCs in mice. These polysaccharide-coated LNCs, especially LNC-LC, are promising templates for targeting ligands (e.g. peptides, proteins) or therapeutic molecules (e.g. siRNA).


Asunto(s)
Lípidos/química , Nanocápsulas , Polisacáridos/química , Activación de Complemento , Células HEK293 , Humanos , Modelos Teóricos , Propiedades de Superficie , Distribución Tisular
8.
Nanomedicine ; 9(3): 375-87, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22960195

RESUMEN

Lipid nanocapsules (LNCs) and lipid nanoemulsions (LNEs) are biomimetic synthetic nanocarriers. Their in vitro and in vivo performance was evaluated as a function of their size (25, 50 and 100 nm) and the surface PEG chain length. Analysis methods included complement activation test, particle uptake in macrophage and HEK293(ß3) cells and biodistribution studies with tumor-grafted mice by fluorescence imaging. A particular attention was paid to keep the concentration of each nanocarrier and to the amount of fluorescent dye in comparable conditions between the in vitro and in vivo studies. Under these conditions, no significant differences were found among the three tested particle sizes and the two nanocarrier types. Longer PEG chains on the LNE surface provided better stealth properties, whereas PEG modification on the LNC formulations inhibited the production of stable nanocarriers. Passive accumulation of LNCs and LNEs in different tumor types depended on the degree of tumor vascularization. FROM THE CLINICAL EDITOR: This study of lipid nanocapsules and lipid nanoemulsions compares their vitro and in vivo performance as a function of size and surface PEG chain length, demonstrating no significant difference among the tested particle sizes. Longer PEG chains on the LNE surface provided better stealth properties, whereas PEG modification on the LNC formulations inhibited the production of stable nanocarriers.


Asunto(s)
Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/farmacocinética , Emulsiones/farmacocinética , Lípidos/farmacocinética , Nanocápsulas/química , Tamaño de la Partícula , Ensayos Antitumor por Modelo de Xenoinjerto , Animales , Materiales Biocompatibles Revestidos/farmacología , Activación de Complemento/efectos de los fármacos , Portadores de Fármacos/química , Endocitosis/efectos de los fármacos , Femenino , Células HEK293 , Humanos , Lípidos/farmacología , Ratones , Ratones Desnudos , Neoplasias/metabolismo , Neoplasias/patología , Tejido Subcutáneo/efectos de los fármacos , Tejido Subcutáneo/patología , Propiedades de Superficie , Distribución Tisular/efectos de los fármacos
9.
Int J Pharm ; 434(1-2): 460-7, 2012 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-22698864

RESUMEN

Deformability of nanoparticles might affect their behaviour at biological interfaces. Lipid nanocapsules (LNCs) are semi-solid particles resembling a hybrid of polymer nanoparticles and liposomes. Deformability of LNCs of different sizes was modelled by drop tensiometer technique. Two purification methods, dialysis and tangential flow filtration (TFF), were applied to study experimental behaviour and deformability of LNCs in order to evaluate if these properties contributed to membrane passing. Rheological parameters obtained from the drop tensiometer analysis suggested decreasing surface deformability of LNCs with increase in diameter. Dialysis results showed that up to 10% of LNCs can be lost during the process (e.g. membrane accumulation) but no clear evidence of the membrane passing was observed. Instead, LNCs with initial size and size distribution could be found in the TFF filtrate although molecular weight cut-off (MWCO) of the membrane used was smaller than the LNC diameter.


Asunto(s)
Lípidos/química , Nanocápsulas , Polímeros/química , Diálisis , Filtración , Membranas/metabolismo , Peso Molecular , Tamaño de la Partícula , Reología
10.
Curr Drug Discov Technol ; 8(3): 188-96, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21513482

RESUMEN

Nanocarriers can penetrate the tumour vasculature through its leaky endothelium and, in this way, accumulate in several solid tumours. This is called the enhanced permeation and retention (EPR) effect. Together with nanocarriers whose surface is tailored for prolonged blood circulation times, the concept is referred to as passive targeting. Targeting ligands, which bind to specific receptors on the tumour cells and endothelium, can be attached on the nanocarrier surface. This active targeting increases the selectivity of the delivery of drugs. Passive and active drug targeting with nanocarriers to tumours reduce toxic side-effects, increase efficacy, and enhance delivery of poorly soluble or sensitive therapeutic molecules. In this review, currently studied and used passive and active targeting strategies in cancer therapy are presented.


Asunto(s)
Antineoplásicos/administración & dosificación , Sistemas de Liberación de Medicamentos , Neoplasias/tratamiento farmacológico , Animales , Antineoplásicos/efectos adversos , Antineoplásicos/farmacocinética , Portadores de Fármacos/química , Endotelio/metabolismo , Humanos , Ligandos , Nanopartículas
11.
Eur J Pharm Biopharm ; 76(2): 200-7, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20656028

RESUMEN

Lipid nanocapsules (LNCs) were modified by adsorbing sequentially dextran sulfate (DS) and chitosan (CS) on their surface by the layer-by-layer (LBL) approach. Tangential flow filtration (TFF) was used in intermediate purifications of the LNC dispersion during the LBL process. The surface modification was based on electrostatic interactions between the coating polyelectrolytes (PEs) and the LNCs. Therefore, a cationic surfactant, lipochitosan (LC), was synthesised by coupling stearic anhydride on chitosan, and the surface of LNCs was first modified by this LC by the post-insertion technique. The PEs could be successfully adsorbed on the LNC surface as verified by alternating zeta potential and increase in size. To present a therapeutic application, fondaparinux sodium (FP), a heparin-like synthetic pentasaccharide, was introduced on the LNC surface instead of DS.


Asunto(s)
Quitosano/química , Sulfato de Dextran/química , Portadores de Fármacos/química , Polisacáridos/administración & dosificación , Adsorción , Anticoagulantes/administración & dosificación , Filtración , Fondaparinux , Nanocápsulas , Electricidad Estática , Tensoactivos/química
12.
J Pharm Biomed Anal ; 51(1): 125-30, 2010 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-19744811

RESUMEN

A novel method for investigating drug release in a dynamic manner from nanoparticles including, but not limited to, biodegradable poly(lactic acid) (PLA) is reported. The PLA nanoparticles were prepared by the nanoprecipitation method. Two poorly soluble drugs, beclomethasone dipropionate (BDP) and indomethacin, were encapsulated into PLA nanoparticles, and their dissolution from the nanoparticles were followed in a dynamic way. The on-line method comprised a short column (vessel) packed with the PLA nanoparticles, on-line connected to an analytical liquid chromatographic column via a multiport switching valve equipped with two loops. The system allowed monitoring of the drug release profiles in real time, and the conditions for the drug release could be precisely controlled and easily changed. The effects of solvent composition and temperature on the rate of dissolution of the drugs from the PLA nanoparticles were investigated. The system proved to be linear for the drugs tested over the concentration range 10-3000 ng (n=6, R(2)=0.999 and 0.997 for indomethacin and beclomethasone, respectively) and repeatable (RSD of peak areas <0.5%). The recoveries of the dissolution study were quantitative (120 and 103% for indomethacin and beclomethasone, respectively).


Asunto(s)
Beclometasona/química , Cromatografía Liquida/métodos , Indometacina/química , Nanopartículas , Antiinflamatorios/química , Antiinflamatorios no Esteroideos/química , Portadores de Fármacos/química , Ácido Láctico/química , Poliésteres , Polímeros/química , Solubilidad , Solventes/química , Temperatura
13.
Int J Pharm ; 377(1-2): 148-52, 2009 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-19426789

RESUMEN

Nanosizing is an advanced formulation approach to address the issues of poor aqueous solubility of active pharmaceutical ingredients. Here we present a procedure to prepare a nanoparticulate formulation with the objective to enhance dissolution kinetics of taxifolin dihydrate, a naturally occurring flavonoid with antioxidant, anti-inflammatory, and hepatoprotective activities. Polyvinylpirrolidone was selected as a carrier and the solid nanodispersions of varying compositions were prepared by a co-precipitation technique followed by lyophilization. The formulation technology reported herein resulted in aggregate-free, spherical particles with the mean size of about 150 nm, as observed by scanning electron microscopy and measured by photon correlation spectroscopy. Furthermore, the co-precipitation process caused taxifolin dihydrate to convert into an amorphous form as verified by X-ray powder diffraction, differential scanning calorimetry, hot stage microscopy and Raman spectroscopy. Finally, in vitro dissolution behavior of the nanodispersion of taxifolin was shown to be superior to that of either pure drug or a drug-polymer physical mixture, reaching 90% of taxifolin released after 30 min. Such enhanced drug release kinetics from the nanodispersion was attributed to both the reduced particle size and the loss of crystallinity.


Asunto(s)
Portadores de Fármacos/farmacocinética , Nanopartículas , Nanotecnología/métodos , Quercetina/análogos & derivados , Tecnología Farmacéutica/métodos , Química Farmacéutica , Portadores de Fármacos/química , Liofilización , Estructura Molecular , Tamaño de la Partícula , Povidona/química , Quercetina/química , Quercetina/farmacocinética
14.
AAPS PharmSciTech ; 10(2): 488-94, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19381823

RESUMEN

Poly(D,L-lactic acid) nanoparticles were freeze-dried in this study. With respect to drying, effect of protective excipients and purification from excess surfactant were evaluated. The nanoparticles were prepared by the nanoprecipitation method with or without a surfactant, poloxamer 188. The particles with the surfactant were used as such or purified by tangential flow filtration. The protective excipients tested were trehalose, sucrose, lactose, glucose, poloxamer 188, and some of their combinations. The best freeze-drying results in terms of nanoparticle survival were achieved with trehalose or sucrose at concentrations 5% and 2% and, on the other hand, with a combination of lactose and glucose. Purification of the nanoparticle dispersion from the excess surfactant prior to the freeze-drying by tangential flow filtration ensured better drying outcome and enabled reduction of the amount of the protective excipients used in the process. The excess surfactant, if not removed, was assumed to interact with the protective excipients decreasing their protective mechanism towards the nanoparticles.


Asunto(s)
Carbohidratos/química , Excipientes/química , Ácido Láctico/química , Nanopartículas/química , Poloxámero/química , Polímeros/química , Tensoactivos/química , Filtración , Liofilización , Microscopía Electrónica , Poliésteres
15.
J Chromatogr A ; 1178(1-2): 248-55, 2008 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-18054945

RESUMEN

Capillary electrophoretic (CE) methods were used for the quantitative determination of model drugs [salbutamol sulphate (SS), sodium cromoglycate (SCG) and beclomethasone dipropionate (BDP)] in poly(D,L-lactic acid) (PLA) nanoparticles, which were prepared by the nanoprecipitation method. Zeta potential and size distribution of the nanoparticles were determined by electrophoretic mobility determinations and photon correlation spectroscopy, respectively. Interactions between the drugs, the PLA nanoparticles and the fused-silica capillary were investigated by electrokinetic capillary chromatography (EKC). A quantitative CE method was developed for salbutamol sulphate and sodium cromoglycate, and the linearity and repeatability of migration times, peak areas and peak heights were determined. Microemulsion electrokinetic chromatography was used for the quantitative determination of beclomethasone dipropionate. According to this study, the applied electromigration techniques were suitable for the interaction, drug entrapment and dissolution studies of pharmaceutical nanoparticles. The results suggest that even quantitation of the drug located inside the nanoparticles was possible. Encapsulation of the more hydrophilic model drugs (SS, SCG) in the PLA nanoparticles was less efficient than in the case of BDP.


Asunto(s)
Portadores de Fármacos , Electroforesis Capilar , Ácido Láctico , Nanopartículas , Preparaciones Farmacéuticas/análisis , Polímeros , Albuterol/análisis , Beclometasona/análisis , Cromolin Sódico/análisis , Portadores de Fármacos/análisis , Microscopía Electrónica de Rastreo , Nanopartículas/análisis , Nanopartículas/ultraestructura , Preparaciones Farmacéuticas/aislamiento & purificación , Poliésteres
16.
J Nanosci Nanotechnol ; 6(9-10): 3110-7, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-17048525

RESUMEN

The chemical and physical stability of polymeric nanoparticles is poor in aqueous suspensions, and the drying of these particles is often problematic. In the present study, the stability of freeze-dried low molecular weight poly(L-lactic acid) (PLA) nanoparticles was enhanced by adding glucose and/or lactose to the formulation as cryo- and lyoprotectants, respectively. Also the effect of an extra stabilizer, Tween 80, was studied. The best freeze-dried PLA nanoparticle formulations were achieved, when glucose and lactose were added in combination so that the amount of lactose was double the amount of glucose. With this combination the redispersion of high-quality nanoparticles (homogenous particle dispersion with original size and without aggregates) was achieved. The addition of Tween 80 further improved the quality of freeze-dried PLA nanoparticles by facilitating the redispersion of the lyophilized cake into optimal nanoparticles.


Asunto(s)
Liofilización/métodos , Glucosa/química , Ácido Láctico/química , Lactosa/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Polímeros/química , Crioprotectores/química , Cristalización/métodos , Estabilidad de Medicamentos , Ácido Láctico/análisis , Ensayo de Materiales , Peso Molecular , Tamaño de la Partícula , Poliésteres , Polímeros/análisis
17.
Colloids Surf B Biointerfaces ; 49(1): 93-9, 2006 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-16616460

RESUMEN

Low molecular weight (M(w)) poly(L-lactic acid) (PLA) nanoparticles were coated with polyelectrolytes (PEs) by layer-by-layer (LbL) technique using a filtration approach. Poly(allylamine hydrochloride) and poly(sodium 4-styrenesulfonate) were applied as PEs in coating. LbL coating is aimed to use in producing (nano)particulate drug delivery systems with improved biocompatibility and sustained or targeted release of drug substances. Nanoparticles of rapidly biodegradable polymers, like the low M(w) PLA, open up a possibility to control the release of the encapsulated substance by the coating, but set challenges to the coating process due to increased aggregation tendency and degradation rate of the polymer. When the core PLA nanoparticles were prepared by nanoprecipitation, surface properties of the nanoparticles were affected by solvent selection. Successful LbL coating of the PLA nanoparticles was obtained only with chloroform, but not with dichloromethane as the solvent during nanoprecipitation. Reason for this was found to be the more charged surface of the nanoparticles prepared with chloroform compared to the nanoparticles prepared with dichloromethane.


Asunto(s)
Electrólitos/química , Ácido Láctico/química , Nanoestructuras/química , Polímeros/química , Microscopía Electrónica de Rastreo , Peso Molecular , Nanoestructuras/ultraestructura , Tamaño de la Partícula , Poliésteres , Propiedades de Superficie , Temperatura
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