The preparation of BSA-PLLA microparticles in a batch supercritical anti-solvent process

Preparation and Optimization of Bovine Serum Albumin Nanoparticles as a Promising Gelling System for Enhanced Nasal Drug Administration

Bovine serum albumin (BSA) has been used extensively as a suitable carrier system for alternative drug delivery routes, such as nasal administration. However, the optimization of BSA nanoparticles with respect to their nasal applicability has not been widely studied. The present study focuses on the characterization of BSA nanoparticles prepared using the desolvation method, followed by a gelation process to facilitate intranasal drug delivery. The results demonstrated that the ratio of BSA and the desolvating agent, ethanol, played a critical role in the nanoparticle characteristics of the BSA nanogel matrices (BSA-NGs). Based on the gelling properties, the formulations of BSA-NG 2, BSA-NG 4, and BSA-NG 6 were selected for further investigation. The Raman spectra confirmed that there were no specific changes to the secondary structures of the BSA. The mucoadhesion studies revealed moderately high mucoadhesive properties, with a mucin binding efficiency (MBE) value of around 67%, allowing the dose to avoid elimination due to rapid mucociliary clearance of the nasal passage. Via studying the nexus of the carrier system, BSA-NGs loaded with dexamethasone as a model drug were prepared and evaluated by differential scanning calorimetry (DSC) and thermal gravimetry (TG), ascertaining that no ethanol remained in the samples after the freeze-drying process. Furthermore, the viscosity measurements exhibited moderate viscosity, which is suitable for nasal liquid preparations. The in vitro release studies performed with a simulated nasal electrolyte solution (SNES) medium showed 88.15-95.47% drug release within 4 h. In conclusion, BSA nanoparticle gelling matrices can offer potential, value-added drug delivery carriers for improved nasal drug administration.

Solid Dosage Forms of Biopharmaceuticals in Drug Delivery Systems Using Sustainable Strategies

Drug delivery systems (DDS) often comprise biopharmaceuticals in aqueous form, making them susceptible to physical and chemical degradation, and therefore requiring low temperature storage in cold supply and distribution chains. Freeze-drying, spray-drying, and spray-freeze-drying are some of the techniques used to convert biopharmaceuticals-loaded DDS from aqueous to solid dosage forms. However, the risk exists that shear and heat stress during processing may provoke DDS damage and efficacy loss. Supercritical fluids (SCF), specifically, supercritical carbon dioxide (scCO₂), is a sustainable alternative to common techniques. Due to its moderately critical and tunable properties and thermodynamic behavior, scCO₂ has aroused scientific and industrial interest. Therefore, this article reviews scCO₂-based techniques used over the year in the production of solid biopharmaceutical dosage forms. Looking particularly at the use of scCO₂ in each of its potential roles—as a solvent, co-solvent, anti-solvent, or co-solute. It ends with a comparison between the compound’s stability using supercritical CO₂-assisted atomization/spray-drying and conventional drying.

Long-circulating lipoprotein-mimic nanoparticles for smart intravenous delivery of a practically-insoluble antineoplastic drug: Development, preliminary safety evaluations and preclinical pharmacokinetic studies

Chlorambucil (CHL) is a water-insoluble antineoplastic drug having a short elimination half-life. It suffers from remarkable differences in pharmacokinetics following oral administration. The current work aimed to assess safety and pharmacokinetics of CHL-loaded, lipoprotein-mimic, nanoparticles (NPs) following intravenous administration. The design of NPs was based on complexation between egg yolk lecithin (EYL) and bovine serum albumin (BSA). The NPs were preliminary evaluated via FT-IR, DSC and P-XRD. The NPs were characterized for particle size, zeta potential, morphology and drug entrapment efficiency (EE%). The best achieved NP dispersion (LP6) and CHL solution were challenged for in vitro hemolytic potential, in vivo vascular irritation studies in rabbits and in vivo pharmacokinetics following intravenous administration in rats. The results confirmed that NPs were stabilized by hydrophobic-attractions and hydrogen-bondings between CHL, BSA and EYL. The amorphous dispersion of CHL within NPs was revealed. LP6 dispersion displayed monodispersed nano-spherical particles (144.33 ± 2.17 nm). It possessed the highest negative zeta potential (-30.55 ± 0.24 mV) and the largest EE% (86.35 ± 2.33%). The significantly (P < 0.05) prolonged MRT(0-∞), longer elimination t50% and reduced plasma clearance highlighted the long-circulating characteristics of LP6. The preliminary safety evaluations and the seven-fold increase in bioavailability elucidated potentiality for smart intravenous delivery of CHL.

Supercritical synthesis of poly (2-dimethylaminoethyl methacrylate)/ferrite nanocomposites for real-time monitoring of protein release

A supercritical carbon dioxide (SCC)-assisted process was developed to synthesize protein-supported poly (2-dimethylaminoethyl methacrylate)/ferrite nanocomposites (PNCs). The process involve 2,2-azobisisobutyronitrile-initiated in situ polymerization of 2-dimethylaminoethyl methacrylate in presence of ferrite nanoparticles and bisacrylamide at 90 ± 1 °C, 1200 psi over 6 h in SCC. This was followed by subsequent loading of bovine serum albumin (BSA) as a model protein over PNCs in phosphate buffer (PBS, pH 7.4) at 1200 psi, 35 ± 1 °C over additional 2 h in SCC. The formation of PNCs was ascertained through ultraviolet-visible, Fourier transform-infrared, X-ray diffraction spectra, transmission electron, atomic force microscopy and magnetometry. The developed process extends large scale production of nanomagnetic PNCs suitable as carrier for protein release applications with optimal release properties. The release of protein from PNCs under in vitro in PBS down to nanomolar range with high temporal resolution, speed and reproducibility was quantified through square wave voltammetry.

Preparation and antitumor effect evaluation of composite microparticles co-loaded with siRNA and paclitaxel by a supercritical process

The co-delivery of siRNA and therapeutic agents provides an effective method for cancer chemotherapy by avoiding drug resistance during the treatment. With a combination of ionic gelation and supercritical fluid technology, nanoparticle-embedded composite microparticles (CMPs) co-loaded with siRNA and paclitaxel (siRNA-PTX-CMPs) were successfully prepared. The results show that CMPs embedded with nanoparticles with a diameter of 50-100 nm exhibited a spherical shape and core-shell structure with a mean diameter of 323 nm. The encapsulation efficiency of siRNA in chitosan nanoparticles (CS NPs) was 96.97%. The drug load and encapsulation efficiency of PTX-loaded CMPs (5% dosage) were 1.40% and 27.95%, respectively; both these increased with an increase in dosage. It was found that no change had occurred in the functional groups of the components during the supercritical process, while the physical form of PTX had shifted to an amorphous state. In the cell experiments, the CMPs clustered around the nucleus after being taken up by the Bcap-37 cells. The results of the antitumor effect experiments revealed that the co-loaded siRNA-PTX-CMPs achieved a significantly better synergistic effect than single dosages, which indicated that the co-delivery system developed by the supercritical process could have potential in the application of cancer chemotherapy.

Tumor-targeted paclitaxel-loaded folate conjugated poly(ethylene glycol)-poly(L-lactide) microparticles produced by supercritical fluid technology

The new biodegradable diblock copolymers poly(ethylene glycol)-poly(L-lactide) (PEG-PLLA) were synthesized and were chemically conjugated with folate (FA) in the PEG terminal ends to form FA-PEG-PLLA. Then the hydrophobic drug paclitaxel (PTX) loaded microparticles (PTX/FA-PEG-PLLA) were produced via solution enhanced dispersion by supercritical fluids (SEDS). These microparticles exhibited sphere-like shape by scanning electron microscopy observation and showed narrow hydrodynamic size distributions by dynamic light scattering measurement. Drug loading of PTX loaded microparticles was about 7-9% and the encapsulation efficiency of PTX loaded microparticles was about 18-23%. Flow cytometry and confocal laser scanning microscope analyses revealed that fluorescein isothiocyanate labeled FA conjugated microparticles presented significantly higher cellular uptake than FA-free group due to the FA-receptor-mediated endocytosis. In vitro cytotoxicity evaluation indicated that FA-PEG-PLLA expressed negligible cytotoxicity to mouse fibroblasts L929 cells. Moreover, PTX/FA-PEG-PLLA microparticles exhibited much higher anti-cancer efficacy than PTX/PEG-PLLA microparticles against human ovarian cancer SKOV3 cells. Nude mice xenografted with SKOV3 cells were used in biodistribution studies, the results indicated that an increased amount of PTX was accumulated in the tumor tissue deal with PTX/FA-PEG-PLLA microparticles. These results collectively suggested that PTX/FA-PEG-PLLA microparticles prepared by SEDS would have potential in anti-tumor applications as a tumor-targeted drug delivery formulation.

Self-assembled serum albumin–poly(l-lactic acid) nanoparticles: a novel nanoparticle platform for drug delivery in cancer

A new protein–hydrophobic polymeric nanoparticle platform BSA–PLLA NPs has been prepared. A large amount of BA was well encapsulated into the BSA–PLLA NPs. Moreover, the BSA–PLLA/BA NPs shows excellent antitumor activity.

Liprosomes loading paclitaxel for brain-targeting delivery by intravenous administration: in vitro characterization and in vivo evaluation

In this study, a lipid-protein nanocomplex (liprosome) was evaluated for its potential use for brain-targeting drug delivery. Liprosome was fabricated with the desolvation-ultrasonication method and characterized in terms of particle size, size distribution, zeta potential, morphology, crystal state of the drug, and in vitro release. The in vivo distribution of paclitaxel loading lipid-protein nanocomplex (PTX-liprosome) and Taxol were compared after i.v. administration in mice. The prepared PTX-liprosome has a high entrapment efficiency (>90%), small particle size (approximately 110 nm), and narrow distribution (P.I.<0.2). Transmission electron microscopy (TEM) indicated that liprosome had a spherical multilayer structure. X-ray photoelectron spectroscopy (XPS) showed that the conjugate of PTX and BSA was in the interior of the PTX-liprosome. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) demonstrated that the drug existed in a molecular or amorphous state. Fourier transform infrared spectroscopy (FTIR) suggested that the hydrophobic interactions, electrostatic interactions and hydrogen bonds among of the PTX, lipid and protein play an important role during the formation of the PTX-liprosome. The hemolysis test showed a good safety profile for the intravenous administration of liprosome. The result of the in vivo distribution suggested that liprosome increased the drug uptake by the brain tissue and decreased drug accumulation in non-target organs. Therefore, liprosome is a potential drug delivery system for transporting PTX to the brain.

Preparation of Chitosan-Based Hemostatic Sponges by Supercritical Fluid Technology

Using ammonium bicarbonate (AB) particles as a porogen, chitosan (CS)-based hemostatic porous sponges were prepared in supercritical carbon dioxide due to its low viscosity, small surface tension, and good compatibility with organic solvent. Fourier transform infrared spectroscopy (FTIR) spectra demonstrated that the chemical compositions of CS and poly-(methyl vinyl ether-co-maleic anhydride) (PVM/MA) were not altered during the phase inversion process. The morphology and structure of the sponge after the supercritical fluid (SCF) process were observed by scanning electron microscopy (SEM). The resulting hemostatic sponges showed a relatively high porosity (about 80%) with a controllable pore size ranging from 0.1 to 200 μm. The concentration of PVM/MA had no significant influence on the porosity of the sponges. Comparative experiments on biological assessment and hemostatic effect between the resulting sponges and Avitene^® were also carried out. With the incorporation of PVM/MA into the CS-based sponges, the water absorption rate of the sponges increased significantly, and the CS-PVM/MA sponges showed a similar water absorption rate (about 90%) to that of Avitene^®. The results of the whole blood clotting experiment and animal experiment also demonstrated that the clotting ability of the CS-PVM/MA sponges was similar to that of Avitene^®. All these results elementarily verified that the sponges prepared in this study were suitable for hemostasis and demonstrated the feasibility of using SCF-assisted phase inversion technology to produce hemostatic porous sponges.

Preparation, characterization and in vitro release properties of morphine-loaded PLLA-PEG-PLLA microparticles via solution enhanced dispersion by supercritical fluids

Morphine-loaded poly(L-lactide)-poly(ethylene glycol)-poly(L-lactide) (PLLA-PEG-PLLA) microparticles were prepared using solution enhanced dispersion by supercritical CO2 (SEDS). The effects of process variables on the morphology, particles size, drug loading (DL), encapsulation efficiency and release properties of the microparticles were investigated. All particles showed spherical or ellipsoidal shape with the mean diameter of 2.04-5.73 μm. The highest DL of 17.92 % was obtained when the dosage ratio of morphine to PLLA-PEG-PLLA reached 1:5, and the encapsulation efficiency can be as high as 87.31 % under appropriate conditions. Morphine-loaded PLLA-PEG-PLLA microparticles displayed short-term release with burst release followed by sustained release within days or long-term release lasted for weeks. The degradation test of the particles showed that the degradation rate of PLLA-PEG-PLLA microparticles was faster than that of PLLA microparticles. The results collectively suggest that PLLA-PEG-PLLA can be a promising candidate polymer for the controlled release system.