Focused Ultrasound as a Scalable and Contact-Free Method to Manufacture Protein-Loaded PLGA Nanoparticles

Interaction of surfactant coated PLGA nanoparticles with in vitro human brain-like endothelial cells

Treatment for CNS related diseases are limited by the difficulty of the drugs to cross the blood-brain barrier (BBB). The functionalization of polymeric nanoparticles (NPs) coated with the surfactants polysorbate 80 (PS80) and poloxamer 188 (P188), have shown promising results as drugs carriers are able to cross the BBB on animal models. In this study, poly(lactide-co-glycolide) (PLGA) NPs coated with PS80 and P188, labelled with a fluorescent dye were tested on human pre-clinical in vitro model to evaluate and compare their uptake profiles, mechanisms of transport and crossing over human brain-like endothelial cells (BLECs) mimicking the human BBB. In addition, these NPs were produced using a method facilitating their reproducible production at high scale, the MicroJet reactor® technology. Results showed that both formulations were biocompatible and able to be internalized within the BLECs in different uptake profiles depending on their coating: P188 NP showed higher internalization capacity than PS80 NP. Both NPs uptakes were ATP-dependent, following more than one endocytosis pathway with colocalization in the early endosomes, ending with a NPs release in the brain compartment. Thus, both surfactant-coated PLGA NPs are interesting formulations for delivery to the brain through the BBB, presenting different uptake profiles.

Industrial Scale Manufacturing and Downstream Processing of PLGA-Based Nanomedicines Suitable for Fully Continuous Operation

Despite the efficacy and potential therapeutic benefits that poly(lactic-co-glycolic acid) (PLGA) nanomedicine formulations can offer, challenges related to large-scale processing hamper their clinical and commercial development. Major hurdles for the launch of a polymeric nanocarrier product on the market are batch-to-batch variations and lack of product consistency in scale-up manufacturing. Therefore, a scalable and robust manufacturing technique that allows for the transfer of nanomedicine production from the benchtop to an industrial scale is highly desirable. Downstream processes for purification, concentration, and storage of the nanomedicine formulations are equally indispensable. Here, we develop an inline sonication process for the production of polymeric PLGA nanomedicines at the industrial scale. The process and formulation parameters are optimized to obtain PLGA nanoparticles with a mean diameter of 150 ± 50 nm and a small polydispersity index (PDI < 0.2). Downstream processes based on tangential flow filtration (TFF) technology and lyophilization for the washing, concentration, and storage of formulations are also established and discussed. Using the developed manufacturing and downstream processing technologies, production of two PLGA nanoformulations encasing ritonavir and celecoxib was achieved at 84 g/h rate. As a measure of actual drug content, encapsulation efficiencies of 49.5 ± 3.2% and 80.3 ± 0.9% were achieved for ritonavir and celecoxib, respectively. When operated in-series, inline sonication and TFF can be adapted for fully continuous, industrial-scale processing of PLGA-based nanomedicines.

PLGA-based nanomedicines manufacturing: Technologies overview and challenges in industrial scale-up

Nanomedicines based on poly(lactic-co-glycolic acid) (PLGA) carriers offer tremendous opportunities for biomedical research. Although several PLGA-based systems have already been approved by both the Food and Drug Administration (FDA) and the European Medicine Agency (EMA), and are widely used in the clinics for the treatment or diagnosis of diseases, no PLGA nanomedicine formulation is currently available on the global market. One of the most impeding barriers is the development of a manufacturing technique that allows for the transfer of nanomedicine production from the laboratory to an industrial scale with proper characterization and quality control methods. This review provides a comprehensive overview of the technologies currently available for the manufacturing and analysis of polymeric nanomedicines based on PLGA nanoparticles, the scale-up challenges that hinder their industrial applicability, and the issues associated with their successful translation into clinical practice.

Towards a Continuous Manufacturing Process of Protein-Loaded Polymeric Nanoparticle Powders

To develop a scalable and efficient process suitable for the continuous manufacturing of poly(lactic-co-glycolic acid) (PLGA) nanoparticles containing ovalbumin as the model protein. PLGA nanoparticles were prepared using a double emulsification spray-drying method. Emulsions were prepared using a focused ultrasound transducer equipped with a flow cell. Either poly(vinyl alcohol) (PVA) or poloxamer 407 (P-407) was used as a stabilizer. Aliquots of the emulsions were blended with different matrix excipients and spray dried, and the yield and size of the resuspended nanoparticles was determined and compared against solvent displacement. Nanoparticle sizes of spray-dried PLGA/PVA emulsions were independent of the matrix excipient and comparable with sizes from the solvent displacement method. The yield of the resuspended nanoparticles was highest for emulsions containing trehalose and leucine (79%). Spray drying of PLGA/P-407 emulsions led to agglomerated nanoparticles independent of the matrix excipient. PLGA/P-407 nanoparticles pre-formed by solvent displacement could be spray dried with limited agglomeration when PVA was added as an additional stabilizer. A comparably high and economically interesting nanoparticle yield could be achieved with a process suitable for continuous manufacturing. Further studies are needed to understand the robustness of a continuous process at commercial scale.

Microfluidics as tool to prepare size-tunable PLGA nanoparticles with high curcumin encapsulation for efficient mucus penetration

Great challenges still remain to develop drug carriers able to penetrate biological barriers (such as the dense mucus in cystic fibrosis) and for the treatment of bacteria residing in biofilms, embedded in mucus. Drug carrier systems such as nanoparticles (NPs) require proper surface chemistry and small size to ensure their permeability through the hydrogel-like systems. We have employed a microfluidic system to fabricate poly(lactic-co-glycolic acid) (PLGA) nanoparticles coated with a muco-penetrating stabilizer (Pluronic), with a tunable hydrodynamic diameter ranging from 40 nm to 160 nm. The size dependence was evaluated by varying different parameters during preparation, namely polymer concentration, stabilizer concentration, solvent nature, the width of the focus mixing channel, flow rate ratio and total flow rate. Furthermore, the influence of the length of the focus mixing channel on the size was evaluated in order to better understand the nucleation-growth mechanism. Surprisingly, the channel length was revealed to have no effect on particle size for the chosen settings. In addition, curcumin was loaded (EE% of ≈68%) very efficiently into the nanoparticles. Finally, the permeability of muco-penetrating PLGA NPs through pulmonary human mucus was assessed; small NPs with a diameter of less than 100 nm showed fast permeation, underlining the potential of microfluidics for such pharmaceutical applications.

AIEgen based poly(L-lactic-co-glycolic acid) magnetic nanoparticles to localize cytokine VEGF for early cancer diagnosis and photothermal therapy

Aim: We demonstrated a novel theranostic system for simultaneous photothermal therapy and magnetic resonance imaging applicable to early diagnostics and treatment of cancer cells. Materials & methods: Oleic acid-Fe3O4 and triphenylamine-divinylanthracene-dicyano were loaded to the poly(L-lactic-co-glycolic acid) nanoparticles (NPs) on which anti-VEGF antibodies were modified to form anti-VEGF/OA-Fe3O4/triphenylamine-divinylanthracene-dicyano@poly(L-lactic-co-glycolic acid) NPs. The 1H nuclear magnetic resonance (NMR), mass spectra, fluorescence, UV absorption, dynamic light scattering, transmission electron microscope and inductively coupled plasma mass spectrometry tests were used to characterize the NPs, and the bioimaging was illustrated by confocal laser scanning microscope (CLSM) and in vivo MRI animal experiment. Results: This system was capable to recognize the overexpressed VEGF-A as low as 68 pg/ml in different cell lines with good selectivity and photothermal therapy effect. Conclusion: These ultrasensitive theranostic NPs were able to identify tumor cells by fluorescence imaging and MRI, and destroy tumors under near infrared illumination.

Multivariate analysis for the optimization of microfluidics-assisted nanoprecipitation method intended for the loading of small hydrophilic drugs into PLGA nanoparticles

Design of Experiment-assisted evaluation of critical process (total flow rate, TFR, flow rate ratio, FRR) and formulation (polymer concentration and structure, drug:polymer ratio) variables in a novel microfluidics-based device, a staggered herringbone micromixer (SHM), for poly(lactic-co-glycolic acid) copolymer (PLGA) nanoparticles (NPs) manufacturing was performed in order to systematically evaluate and mathematically describe their effects on NPs sizes and drug encapsulation; a small hydrophilic moiety, N-acetylcysteine, was chosen as challenging model drug. SHM-assisted nanoprecipitation method consistently yielded NPs with tailor made sizes (in the range of 100-900 nm) and polydispersity index range from 0.061 to 0.286. Significant effects on NPs sizes were highlighted for TFR and FRR: increasing TFR (from 5 to 15 mL/min) and decreasing FRR (from 1:1 to 1:5 v/v, acetonitrile: buffer) NPs with mean diameter <200 nm were obtained. SHM technique allowed for flexible, application-specific tuning of PLGA NPs size using organic solvents with relatively low toxicity (acetone, acetonitrile), varying aqueous phase composition (Tris buffer vs PVA aqueous solution) and PLGA characteristics (Mw ranging from 25-90 kDa, capped or un-capped PLGA, different lactide:glycolide molar ratio). A very satisfactory N-Ac encapsulation efficiency (more than 67%) and a prolonged release (by 168 h) were achieved.

Influence of different stabilizers on the encapsulation of desmopressin acetate into PLGA nanoparticles

To address targeting and bioavailability issues of peptidic drugs like desmopressin, the encapsulation into nanoparticles (NP) has become standard in pharmaceutics. This study investigated the encapsulation of desmopressin into PLGA NP by the use of pharmaceutically common stabilizers as a precursor to future, optional targeting and bioavailability experiments. Polymer dry weights were measured by freeze drying and thermo gravimetric analysis (TGA). Particle sizes (ranging between 105 and 130nm, PDI<0.1) and zeta potentials (-35 to -45mV) were analyzed with Dynamic Light Scattering (DLS) and Laser-Doppler-Anemometry (LDA) respectively. Highest loading efficiencies, quantified by RP-HPLC, were achieved with Pluronic F-68 as stabilizer of the inner aqueous phase (1.16±0.07μg desmopressin/mg PLGA) and were significantly higher than coating approaches and approaches without stabilizer (0.74±0.01μg/mg). Optimized nanoformulations are thus in competition with the concentration of commercial non-nanoparticulate desmopressin products. Stability of desmopressin after the process was evaluated by HPLC peak purity analysis (diode array detector) and by mass spectrometry. Desmopressin was shown to remain intact during the whole process; however, despite these very good results the encapsulation efficiency turned out to be a bottle neck and makes the system a challenge for potential applications.

Design of smart GE11-PLGA/PEG-PLGA blend nanoparticulate platforms for parenteral administration of hydrophilic macromolecular drugs: synthesis, preparation and in vitro/ex vivo characterization

Active drug targeting and controlled release of hydrophilic macromolecular drugs represent crucial points in designing efficient polymeric drug delivery nanoplatforms. In the present work EGFR-targeted polylactide-co-glycolide (PLGA) nanoparticles were made by a blend of two different PLGA-based polymers. The first, GE11-PLGA, in which PLGA was functionalized with GE11, a small peptide and EGFR allosteric ligand, able to give nanoparticles selective targeting features. The second polymer was a PEGylated PLGA (PEG-PLGA) aimed at improving nanoparticles hydrophilicity and stealth features. GE11 and GE11-PLGA were custom synthetized through a simple and inexpensive method. The nanoprecipitation technique was exploited for the preparation of polymeric nanoparticles composed by a 1:1weight ratio between GE11-PLGA and PEG-PLGA, obtaining smart nanoplatforms with proper size for parenteral administration (143.9±5.0nm). In vitro cellular uptake in EGFR-overexpressing cell line (A549) demonstrated an active internalization of GE11-functionalized nanoparticles. GE11-PLGA/PEG-PLGA blend nanoparticles were loaded with Myoglobin, a model hydrophilic macromolecule, reaching a good loading (2.42% respect to the theoretical 4.00% w/w) and a prolonged release over 60days. GE11-PLGA/PEG-PLGA blend nanoparticles showed good in vitro stability for 30days in physiological saline solution at 4°C and for 24h in pH 7.4 or pH 5.0 buffer at 37°C respectively, giving indications about potential storage and administration conditions. Furthermore ex vivo stability study in human plasma using fluorescence Single Particle Tracking (fSPT) assessed good GE11-PLGA/PEG-PLGA nanoparticles dimensional stability after 1 and 4h. Thanks to the versatility in polymeric composition and relative tunable nanoparticles features in terms of drug incorporation and release, GE11-PLGA/PEG-PLGA blend NPs can be considered highly promising as smart nanoparticulate platforms for the treatment of diseases characterized by EGFR overexpression by parenteral administration .