Size Of Polymeric Nanoparticles Research Articles

Impact of formulation on the quality and stability of freeze-dried nanoparticles

Freeze-drying is an effective approach to improve the long-term stability of nanomedicines. Lyoprotectants are generally considered as requisite excipients to ensure that the quality of nanoparticles is maintained throughout the freeze-drying process. However, depending on the type of nanoparticles, the needs for lyoprotectants or the challenges they face during freeze-drying may be different. In this study, we compared and identified the impact of freeze-drying on key characteristics of three types of nanoparticles: solid lipid nanoparticles (SLNs), polymeric nanoparticles (PNs), and liposomes. Sucrose, trehalose, and mannitol were added to nanoparticle suspensions before freeze-drying. The same conservative freeze-drying conditions with controlled ice nucleation at −8 °C were employed for all formulations. The collapse temperatures of nanoparticle formulations were found to be the same as those of the lyoprotectant added, except PN formulation. Likely the poly(vinyl alcohol) (PVA) in the formulation induced a higher collapse temperature and retardation of drying of PNs. Freeze-drying of both SLNs and liposomes without lyoprotectants increased particle size and polydispersity, which was resolved by adding amorphous disaccharides. Regardless of the addition of lyoprotectants, freeze-drying did not alter the size of PNs possibly due to the protection from PVA. However, lyoprotectants were still necessary to shorten the reconstitution time and reduce the residual moisture. In conclusion, different types of nanoparticles face distinct challenges for freeze-drying, and lyoprotectants differentially affect various stability and quality attributes of freeze-dried nanoparticles.

Synthesis, characterization, morphology and adsorption performance towards cu+2 ions of nano-sized copolymers of anthranilic acid and o-aminophenol poly(anthranilic acid-co-o-aminophenol)

Nanospheres with different particles size and nanorodes of copolymer of anthranilic acid with o-aminophenol poly(AA-co-o-AP) were synthesized by redox polymerization initiated by FeSO4.7H2O as redox initiator and ammonium peroxydisulfate (APS) as oxidant in different concentrations of aqueous solutions of hydrochloric acid. The influence of synthetic parameters such as acid concentration and the presence of redox initiator were investigated. The morphology and particles size were studied by transmission electron microscope (TEM) and scanning electron microscope (SEM). The results showed that the morphology and average particle size of polymeric nano particles according to SEM and TEM analyses were different based upon the conditions of the copolymerization. The physico-chemical characterization of the prepared nanoparticles was carried out by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and Thermogravimetric(TGA). Which FT-IR confirmed the structure of poly(AA-co-o-AP) nanoparticles in emeraldine form. The molecular weight was determined by gel permeation chromatography (GPC). The surface area of nanocopolymer particles was determined also by Brunauer-Emmett-Teller (BET). The competition of the prepared nano-sized copolymers particles towards the adsorption of copper ions from aqueous solutions was investigated. The results showed that the adsorption capacity was based on particle size of nanocopolymers and their surface area. The adsorption capacity increased with decreasing the particle size. On the other hand the adsorption capacity increased with increasing the surface area and the molecular weight of the prepared nano-sized copolymers of poly(AA-co-o-AP).

Synthesis, characterization, morphology and adsorption performance towards Cu+2 ions of nano-sized copolymers of anthranilic acid and o-phenylenediamine poly(AA-co-o-PD)

Nanorodes, nanosheets, nanospheres and nano-amorphous shape with different particles size of copolymer of anthranilic acid with o-phenylenediamine poly(AA-co-o-PD) were synthesized by redox polymerization initiated by FeSO4.7H2O as redox initiator and ammonium peroxydisulfate (APS) as oxidant in different concentrations of aqueous solutions of hydrochloric acid. The influence of synthetic parameters such as acid concentration and the presence of redox initiator were investigated. The morphology and particles size were studied by transmission electron microscope (TEM) and scanning electron microscope (SEM). The results showed that the morphology and average particle size of polymeric nano particles according to SEM and TEM analyses were different based upon the conditions of the copolymerization. The physico-chemical characterization of the prepared nanoparticles was carried out by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD). Which FT-IR confirmed the structure of poly(AA-co-o-PD) nanoparticles in emeraldine form. The molecular weight was determined by gel permeation chromatography (GPC). The surface area of nanocopolymer particles was determined also by Brunauer-Emmett-Teller (BET). The competition of the prepared nano-sized copolymers particles towards the adsorption of copper ions from aqueous solutions was investigated. The results showed that the adsorption capacity was based on particle size of nanocopolymers and their surface area. The adsorption capacity increased with decreasing the particle size. On the other hand the adsorption capacity increased with increasing the surface area of the prepared nano-sized copolymers of poly(AA-co-o-PD).

Investigation of Effective Parameters on Size of Paclitaxel Loaded PLGA Nanoparticles.

Purpose: The size of polymeric nanoparticles is considered as an effective factor in cancer therapy due to enterance into tumor tissue via the EPR effect. The purpose of this work was to investigate the effective parameters on poly(lactic-co-glycolic acid)-paclitaxel (PLGA –PTX) nanoparticles size.Methods: We prepared PLGA-PTX nanoparticles via single emulsion and precipitation methods with variable paremeters including drug concentration, aqueous to organic phase volume ratio, polymer concentration, sonication time and PVA concentration.Results: PLGA-PTX nanoparticles were characterized by dynamic light scattering (DLS) and scanning electron microscopy (SEM). The results exhibited that the diameter of nanoparticles enhanced with increasing drug, polymer and PVA concentrations whereas organic to aqueous phase volume ratio and sonication time required to the optimization for a given size.Conclusion: The precipitation method provides smaller nanoparticles compared to emulsion one. Variable parameters including drug concentration, aqueous to organic phase volume ratio, polymer concentration, sonication time and PVA concentration affect diameter of nanoparticles.

Tuning the Size of Poly(lactic-co-glycolic Acid) (PLGA) Nanoparticles Fabricated by Nanoprecipitation.

Polymeric nanoparticles (PNPs) are promising drug carriers in cancer treatment. Size of the particles has a significant impact on drug loading, in vivo distribution, extravasation, intratumor diffusion and cell uptake, and thus is critical for the successful development of a drug delivery regime. However, methods for manufacturing PNPs of defined size are yet to be established. The goal of this study is to establish a method that can be used to fabricate PNPs with controlled size. The factors that could impact the size of PNPs fabricated by nano-precipitation are systematically investigated. The factors studied include polymer concentration, organic solvent, temperature, aqueous phase ionic strength, organic phase injection rate, aqueous phase agitation rate, gauge of the needles, and final polymer concentration. Polymer concentration, the choice of organic solvent, temperature, and the ionic strength of the aqueous phase are shown to have a significant impact on the size of PNPs, and the effect of these factors can be attributed to a single parameter, the diffusion coefficient of the solvent in water, Dpw . It is possible that by tightly control these four parameters, nanoparticles with highly predictable and desirable size with narrow size distribution can be fabricated.

Synthesis, characterization and ultrasonic study of aqueous suspensions containing polymeric nano particles of poly (L-lactide)

Aqueous suspensions containing polymeric nano particles (PNPs) of Poly (L-lactide) are prepared by interfacial deposition in two different mixed solvents (dichloromethane+n-hexane and dichloromethane+chloroform) and in the presence of stabilizers. The PNPs are characterized by FT-IR spectra, DSC and XRD measurements. The particle size is determined by TEM analysis and dynamic light scattering method. The influence of solvent on the size, shape and physicochemical properties such as crystalline nature, degree of dispersion, melting temperature, and stability of the suspensions is investigated. The size of PNPs is correlated with ultrasonic velocity and degree of dispersion with absorption coefficient. Experimental density and ultrasonic velocity values are compared with those calculated using theoretical Urick, Kuster–Toksöz and Urick–Ament models.

Optimization of paclitaxel-loaded poly (d,l-lactide-co-glycolide-N-p-maleimido benzoic hydrazide) nanoparticles size using artificial neural networks

The aim of this study was to find a model using artificial neural networks (ANNs) to predict PLGA-PMBH nanoparticles (NPs) size in preparation by modified nanoprecipitation. The input variables were polymer content, drug content, power of sonication and ratio of organic/aqueous phase (i.e. acetone/water), while the NPs size of PLGA-PMBH was assumed as the output variable. Forty samples of PLGA-PMBH NPs containing anticancer drug (i.e. paclitaxel) were synthesized by changing the variable factors in the experiments. The data modeling were performed using ANNs. The effects of input variables (namely, polymer content, drug content, power of sonication and ratio of acetone/water) on the output variables were evaluated using the 3D graphs obtained after modeling. Contrasting the 3D graphs from the generated model revealed that the amount of polymer (PLGA-PMBH) and drug content (PTX) have direct relation with the size of polymeric NPs in the process. In addition, it was illustrated that the ratio of acetone/water was the most important factor affecting the particle size of PLGA-PMBH NPs provided by solvent evaporation technique. Also, it was found that increasing the sonication power (up to a certain amount) indirectly affects the polymeric NPs size however it was directly affected in higher values.

Synthesis, Structure, and Properties of C60-Pd Spherical Nanoparticles

Synthesis, structure, and properties of C60-Pd spherical nanoparticles Krzysztof Winkler, Emilia Gradzka, Ewa Brancewicz Institute of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Bialystok, Poland The C60-Pd polymer can be synthesized electrochemically1 or chemically.2 The electrochemical synthesis results in the formation of thin and uniform film on the electrode surface. The film is electrochemically active at negative potentials due to the fullerene cages reduction.1 The chemical synthesis of C60-Pd polymer, carried out in benzene solution containing Pd2(dba)3·CHCl3 and fullerene C60, results in formation of large crystalline superficial structures which are composed of a small spherical particles 20-200 nm in diameter (Fig. 1). These cubic semi-crystals can be disintegrated to spherical nanoparticles with the high energy ultrasound. The size of synthesized C60-Pd nanoparticles can be controlled by composition of grown solution, time of polymerization, temperature of synthesis, and stirring conditions. The most uniform in size particles were synthesized in solution containing 3:1 ratio of [Pd] to [C60] concentration. Dispersed C60-Pd nanoparticles are stable in many organic protic and aprotic solvents. The electrochemical properties of films formed from chemically synthesized nanoparticles were investigated. Special attention was paid to capacitance properties. The electrochemical behavior of these films resembles the one observed for electrochemically synthesized polymers. Capacitance properties of films formed from C60-Pd nanoparticles depend on the size of polymeric nanoparticles. The specific capacitance of polymer formed in solution containing 1:1 ratio of [Pd] to [C60] reaches the value obtained earlier for electrochemically synthesized material. The electrochemical properties of colloidal solutions of C60-Pd nanoparticles were also studied using ultramicroelectrodes. Diffusion controlled voltammograms are recorded for these systems. Two component nanoparticlec composed of C60-Pd core and polypyrrole shell were synthesized. The electrochemical properties of such p-nspherical nanojunction were studied both in solid phase and in the solution. Fig. 1. SEM (left panels) and TEM (right panels) images of chemically synthesized C60-Pd in benzene solution containing 0.48 mM C60 and 0.73 mM Pd2(dba)3·CHCl3 1. A.L. Balch, D.A.Costa, K. Winkler, J. Am. Chem. Soc., 120, 9614 (1998).2. H. Nagashima, A. Nakaoka, Y. Saito, M. Kato, T. Kawanishi, K. Lotha, J. Chem. Soc. Chem. Commun., 377-379 (1992).

Facile synthesis of size-tunable stable nanoparticles via click reaction for cancer drug delivery

The stability and size of polymeric nanoparticles are two of the most important parameters determining their pharmacokinetics and tumor/drug accumulation efficiency in cancer-drug delivery. Herein, we report a facile one-pot synthesis of crosslinked nanoparticles (CNPs) with tunable sizes and polyethylene glycol (PEG) shells via click reactions. Simply by adjusting the contents of the macromonomer (PEG monoacrylate) in its reaction with ethylene diacrylate and a crosslinker containing hexa-thiols groups, the sizes of the resulting PEGylated crosslinked nanoparticles could be easily tuned from 10 to 90 nm. These nanoparticle cores could encapsulate hydrophobic drugs such as doxorubicin (DOX), and the unreacted thiol and acrylate groups could be used for drug conjugation or labeling. Thus, the nanoparticles provide a multifunctional platform for drug delivery. In vivo studies showed that the larger nanoparticles (about 83.7 nm) had a much longer blood-circulation time and better tumor-targeting efficiency. One of our most important findings was that the drug encapsulated in the crosslinked nanoparticles, even though little was released at pH 7.4 under in vitro conditions, had much faster blood clearance than the nanoparticles’ carrier, suggesting that drug release in the bloodstream was significant.

Chemical synthesis and characterization of the C60-Pd polymer spherical nanoparticles

The chemical synthesis of C60-Pd polymer carried out in benzene solution containing Pd2(dba)3·CHCl3 and fullerene C60 results in formation of large cubic particles with size ranges from 20 to 80μm which are composed of a small spherical nanoparticles 20–200nm in diameter. These cubic particles can be disintegrated to spherical nanoparticles with the high energy ultrasound. The size of synthesized C60-Pd nanoparticles can be controlled by the composition of grown solution, time of polymerization, the temperature of synthesis, and the stirring conditions. The most uniform in size particles were synthesized in solution containing 3:1 ratio of [Pd] to [C60] concentration. Dispersed C60-Pd nanoparticles are stable in many organic protic and aprotic solvents. The Hansen dispersive force parameter, δd, and dipole–dipole interaction parameter, δp, govern the stability of C60-Pd dispersions. The electrochemical properties of films formed from chemically synthesized nanoparticles were investigated. Special attention was paid to capacitance properties. The electrochemical behavior of these films resembles the one observed for electrochemically synthesized polymers. Electrochemical activity of these materials is related to the reduction of fullerene moieties. Capacitance properties of films formed from C60-Pd nanoparticles depend on the size of polymeric nanoparticles. The specific capacitance of the polymer formed in solution containing 1:1 ratio of [Pd] to [C60] reaches the value reported for the electrochemically synthesized material.

High-performance nanostructure chiral poly(amide–imide)s containing benzamide and amino acid linkages: Preparation, characterization and ultrasonic effect on the morphology

In this research work, several novel optically active nanostructure poly(amide–imide)s (PAIs) were synthesized from the direct polycondensation reaction of 3,5-diamino- N-(pyridin-3-yl) benzamide with chiral diacids based on trimellitic anhydride-derived dicarboxylic acids containing different natural amino acids such as l-methionine, S-valine, l-alanine and l-isoleucine in green medium consisting of molten tetrabutylammonium bromide. The diamine was synthesized by a two-step reaction. At first, 3,5-dinitro- N-(pyridin-3-yl)benzamide was prepared from the reaction of one equimolar of 3-amino pyridine and one mole of 3,5-dinitrobenzoyl chloride. In the next step, the obtained dinitro was reduced by Pd/C and hydrazine hydrate. The new thermally stable optically active PAIs with inherent viscosity ranging from 0.31 to 0.46 dL g−1 were obtained with high yield. The synthesized polymers were characterized with Fourier transform infrared, proton-nuclear magnetic resonance spectroscopy, specific rotation measurements, thermogravimetric analysis, x-ray diffraction, field emission scanning electron microscopy (FE-SEM) and elemental analysis techniques. Morphological study by FE-SEM showed that these new PAIs were noncrystalline and nanostructure polymers with particle size between 50 and 70 nm. The effect of ultrasonic radiation on the obtained nanostructured polymers showed that the size of polymeric nanoparticles was reduced to about 30–45 nm.

Intentional variation of size of polymeric nanoparticles — corpuscular carriers of biologically active compounds

Intentional variation of size of polymeric nanoparticles — corpuscular carriers of biologically active compounds