Continuous production of polymer nanoparticles using a membrane-based flow cell

Sulfonated calixarene modified Poly(methyl methacrylate) nanoparticles:A promising adsorbent for Removal of Vanadium Ions from aqueous media

The poly (methyl methacrylate) (PMMA)-based nanoparticle was synthesized by surfactant-free emulsion polymerization method and then post modified with Calixarene using (3-Aminopropyl)triethoxysilane organo-silane as a linker after OH-treatment. The prepared structure was applied for efficient adsorption of Vanadium ions in the aqueous solution after characterization by FT-IR, SEM, TEM, DLS, and EDX. Additional investigations discovered that the prepared adsorbent has a good capacity to adsorb vanadium ions. The effect of key experimental factors was studied to find the optimal point of adsorbent efficiency including the initial concentration of analyte, sorbent dosage, pH of the solution, contact time, and type/quantity of the eluents. It was specified, the maximum adsorption capacity for the synthesized nanoparticles was obtained about 322 mg g^-1. The adsorption mechanism was revealed that the model of Langmuir isotherm well-matched compared to the others due to the calculated equilibrium data. Besides, the kinetics of the adsorption process was fitted with pseudo-second-order. Eventually, the prepared adsorbent was successfully applied in vanadium adsorption from real water media.

Mucoadhesive PLGA Nanospheres and Nanocapsules for Lactoferrin Controlled Ocular Delivery

Background: the present work describes the preparation, characterization and optimization of eight types of PLGA-based nanosystems (nanospheres and nanocapsules) as innovative mucoadhesive drug delivery systems of lactoferrin, in order to achieve a preclinical consistent base as an alternative pharmacological treatment to different ocular syndromes and diseases. Methods: All different nanoparticles were prepared via two modified nanoprecipitation techniques, using a three-component mixture of drug/polymer/surfactant (Lf/PLGA/Poloxamer), as a way to overcome the inherent limitations of conventional PLGA NPs. These modified polymeric nanocarriers, intended for topical ophthalmic administration, were subjected to in vitro characterization, surface modification and in vitro and in vivo assessments. Results: An appropriate size range, uniform size distribution and negative ζ potential values were obtained for all types of formulations. Lactoferrin could be effectively included into all types of nanoparticles with appropriate encapsulation efficiency and loading capacity values. A greater, extended, and controlled delivery of Lf from the polymeric matrix was observed through the in vitro release studies. No instability or cytotoxicity was proved for all the formulations by means of organotypic models. Additionally, mucoadhesive in vitro and in vivo experiments show a significant increase in the residence time of the nanoparticles in the eye surface. Conclusions: all types of prepared PLGA nanoparticles might be a potential alternative for the topical ophthalmic administration of lactoferrin.

Biocompatible poly(ethylene succinate) polyester with molecular weight dependent drug release properties

In the present study, we demonstrate that well-known molecular weight-dependent solubility properties of a polymer can also be used in the field of controlled drug delivery. To prove this, poly(ethylene succinate) (PES) polyesters with polycondensation time regulated molecular weights were synthesized via catalyst-free direct polymerization in an equimolar ratio of ethylene glycol and succinic acid monomers at 185 °C. DSC and contact angle measurements revealed that increasing the molecular weight (M_w, 4.3-5.05 kDa) through the polymerization time (40-80 min) increased the thermal stability (T_m= ∼61-80 °C) and slightly the hydrophobicity (Θ_w= ∼27-41°) of the obtained aliphatic polyester. Next, this biodegradable polymer was used for the encapsulation of Ca²⁺ channel blocker Nimodipine (NIMO) to overcome the poor water solubility and enhance the bioavailability of the drug. The drug/ polymer compatibility was proved by the means of solubility (δ) and Flory-Huggins interaction (miscibility) parameters (χ). The nanoprecipitation encapsulation of NIMO into PES with increasing M_w resulted in the formation of spherical 270 ± 103 nm NIMO-loaded PES nanoparticles (NPs). Furthermore, based on the XRD measurements, the encapsulated form of NIMO-loaded PES NPs showed lower drug crystallinity, which enhanced not only the water solubility but even the water stability of the NIMO in an aqueous medium. The in-vitro drug release experiments demonstrated that the release of NIMO drug could be accelerated or even prolonged by the molecular weights of PES as well. Due to the low crystallinity of PES polyester and low particle size of the encapsulated NIMO drug led to enhance solubility and releasing process of NIMO from PES with lower M_w (4.3 kDa and 4.5 kDa) compared to pure crystalline NIMO. However, further increasing the molecular weight (5.05 kDa) was already reduced the amount of drug release that provides the prolonged therapeutic effect and enhances the bioavailability of the NIMO drug.

Preparation of Polyetherimide Nanoparticles by a Droplet Evaporation-Assisted Thermally Induced Phase-Separation Method

The droplet evaporation effect on the preparation of polyetherimide (PEI) nanoparticles by thermally induced phase separation (TIPS) was studied. PEI nanoparticles were prepared in two routes. In route I, the droplet evaporation process was carried out after TIPS. In route II, the droplet evaporation and TIPS processes were carried out simultaneously. The surface tension and shape parameters of samples were measured via a drop shape analyzer. The Z-average particle diameter of PEI nanoparticles in the PEI/dimethyl sulfoxide solution (DMSO) suspension at different time points was tested by dynamic light scattering, the data from which was used to determine the TIPS time of the PEI/DMSO solution. The natural properties of the products from both routes were studied by optical microscope, scanning electron microscope and transmission electron microscope. The results show that PEI nanoparticles prepared from route II are much smaller and more uniform than that prepared from route I. Circulation flows in the droplet evaporation were indirectly proved to suppress the growth of particles. At 30 °C, PEI solid nanoparticles with 193 nm average particle size, good uniformity, good separation and good roundness were obtained. Route I is less sensitive to temperature than route II. Samples in route I were still the accumulations of micro and nanoparticles until 40 °C instead of 30 °C in route II, although the particle size distribution was not uniform. In addition, a film structure would appear instead of particles when the evaporation temperature exceeds a certain value in both routes. This work will contribute to the preparation of polymer nanoparticles with small and uniform particle size by TIPS process from preformed polymers.

Finding key nanoprecipitation variables for achieving uniform polymeric nanoparticles using neurofuzzy logic technology

Nanoprecipitation is a simple and fast method to produce polymeric nanoparticles (Np); however, most applications require filtration or another separation technique to isolate the nanosuspension from aggregates or polydisperse particle production. In order to avoid variability introduced by these additional steps, we report here a systematic study of the process to yield monomodal and uniform Np production with the nanoprecipitation method. To further identify key variables and their interactions, we used artificial neural networks (ANN) to investigate the multiple variables which influence the process. In this work, a polymethacrylate derivative was used for Np (NpERS) and a database with several formulations and conditions was developed for the ANN model. The resulting ANN model had a high predictability (> 70%) for NpERS characteristics measured (mean size, PDI, zeta potential, and number of particle populations). Moreover, the model identified production variables leading to polymer supersaturation, such as mixing time and turbulence, as key in achieving monomodal and uniform NpERS in one production step. Polymer concentration and type of solvent, modifiers of polymer diffusion and supersaturation, were also shown to control NpERS characteristics. The ANN study allowed the identification of key variables and their interactions and resulted in a predictive model to study the NpERS production by nanoprecipitation. In turn, we have achieved an optimized method to yield uniform NpERS which could pave way for polymeric nanoparticle production methods with potential in biological and drug delivery applications.