Interfacial properties and micellization of triblock poly(ethylene glycol)-poly(ε-caprolactone)-polyethyleneimine copolymers

This study aimed to explore the link between block copolymers’ interfacial properties and nanoscale carrier formation and found out the influence of length ratio on these characters to optimize drug delivery system. A library of diblock copolymers of PEG-PCL and triblock copolymers with additional PEI (PEG-PCL-PEI) were synthesized. Subsequently, a systematic isothermal investigation was performed to explore molecular arrangements of copolymers at air/water interface. Then, structural properties and drug encapsulation in self-assembly were investigated with DLS, SLS and TEM. We found the additional hydrogen bond in the PEG-PCL-PEI contributes to film stability upon the hydrophobic interaction compared with PEG-PCL. PEG-PCL-PEI assemble into smaller micelle-like (such as PEG-PCL4006-PEI) or particle-like structure (such as PEG-PCL8636-PEI) determined by their hydrophilic and hydrophobic block ratio. The distinct structural architectures of copolymer are consistent between interface and self-assembly. Despite the disparity of constituent ratio, we discovered the arrangement of both chains guarantees balanced hydrophilic–hydrophobic ratio in self-assembly to form stable construction. Meanwhile, the structural differences were found to have significant influence on model drugs incorporation including docetaxel and siRNA. Taken together, these findings indicate the correlation between molecular arrangement and self-assembly and inspire us to tune block compositions to achieve desired nanostructure and drug loading.     

Inactivated infectious bronchitis virus vaccine encapsulated in chitosan nanoparticles induces mucosal immune responses and effective protection against challenge

Avian infectious bronchitis virus (IBV) is one of the most important viral diseases of poultry. The mucosa of upper respiratory tract, specially the trachea, is the primary replication site for this virus. However, conventional inactivate IBV vaccines usually elicit reduced mucosal immune responses and local protection. Thus, an inactivated IBV vaccine containing BR-I genotype strain encapsulated in chitosan nanoparticles (IBV-CS) was produced by ionic gelation method to be administered by oculo-nasal route to chickens. IBV-CS vaccine administered alone resulted in markedly mucosal immune responses, characterized by high levels of anti-IBV IgA isotype antibodies and IFNγ gene expression at 1dpi. The association of live attenuated Massachusetts IBV and IBV-CS vaccine also induced strong mucosal immune responses, though a switch from IgA isotype to IgG was observed, and IFNγ gene expression peak was late (at 5 dpi). Efficacy of IBV-CS was evaluated by tracheal ciliostasis analysis, histopathology examination, and viral load determination in the trachea and kidney. The results indicated that IBV-CS vaccine administered alone or associated with a live attenuated heterologous vaccine induced both humoral and cell-mediated immune responses at the primary site of viral replication, and provided an effective protection against IBV infection at local (trachea) and systemic (kidney) sites.     

Design of a Small-Scale Multi-Inlet Vortex Mixer for Scalable Nanoparticle Production and Application to the Encapsulation of Biologics by Inverse Flash NanoPrecipitation

Flash NanoPrecipitation is a scalable approach to generate polymeric nanoparticles using rapid micromixing in specially designed geometries such as a confined impinging jets mixer or a Multi-Inlet Vortex Mixer (MIVM). A major limitation of formulation screening using the MIVM is that a single run requires tens of milligrams of the therapeutic. To overcome this, we have developed a scaled-down version of the MIVM, requiring as little as 0.2 mg of therapeutic, for formulation screening. The redesigned mixer can then be attached to pumps for scale-up of the identified formulation. It was shown that Reynolds number allowed accurate scaling between the 2 MIVM designs. The utility of the small-scale MIVM for formulation development was demonstrated through the encapsulation of a number of hydrophilic macromolecules using inverse Flash NanoPrecipitation with target loadings as high as 50% by mass.     

Nanostructured liquid crystalline formulation as a remarkable new drug delivery system of anti-epileptic drugs for treating children patients

Purpose

Development of a new dosage-form of antiepileptic-drugs appropriated for children.

Enhanced doxorubicin delivery to hepatocellular carcinoma cells via CD147 antibody-conjugated immunoliposomes

HAb18G/CD147, an important marker in the progression of hepatocellular carcinoma (HCC), is highly expressed on the surface of HCC cells. To increase the therapeutic efficacy of Doxil (PEGylated liposomal doxorubicin) against HCC, we constructed CD147-targeted doxorubicin-loaded immunoliposomes (Anti-CD147 ILs-DOX) by conjugating F(ab’)2 of a CD147-specific monoclonal antibody to DSPE-PEG-MAL, and then inserted the antibody-conjugated polymer to Doxil. Anti-CD147 ILs-DOX delivered DOX to CD147-overexpressing HCC cells specifically and efficiently in vitro and in vivo, resulting in enhanced therapeutic effects than non-targeted controls. Strikingly, Anti-CD147 ILs-DOX reduced the CD133-positive fraction of HCC cells, suggesting its potential in reducing the number of HCC stem cells. Pharmacokinetic and biodistribution studies of Anti-CD147 ILs-DOX confirmed its long circulation time and efficient accumulation in tumors. The superior antitumor effects of Anti-CD147 ILs-DOX than other treatments were demonstrated in both HCC cells and patient-derived HCC xenograft models. Anti-CD147 ILs-DOX represent a novel approach for targeted HCC therapy.     

Amphotericin B-loaded polymeric nanoparticles: formulation optimization by factorial design

In this study, PLGA or PLGA-PEG blend nanoparticles were developed loading amphotericin B (AmB), an antifungal agent broadly used in therapy. A 2²?×?3¹ factorial experimental design was conducted to indicate an optimal formulation of nanoparticles containing AmB and demonstrate the influence of the interactions of components on the mean particle size and drug encapsulation efficiency. The independent variables analyzed were polymer amount (two levels) and organic phase (three factors in one level). The parameters methanol as cosolvent and higher polymer amount originated from the higher AmB encapsulation, but with the larger particle size. The selected optimized parameters were set as the lower polymer amount and ethyl acetate as cosolvent in organic phase, for both PLGA and PLGA-PEG nanoparticles. These parameters originated from nanoparticles with the size of 189.5?±?90?nm and 169?±?6.9?nm and AmB encapsulation efficiency of 94.0?±?1.3% and 92.8?±?2.9% for PLGA and PLGA-PEG nanoparticles, respectively. Additionally, these formulations showed a narrow size distribution indicating homogeneity in the particle size. PLGA and PLGA-PEG nanoparticles are potential carrier for AmB delivery and the factorial design presented an important tool in optimizing nanoparticles formulations.     

Transgene regulation system responding to Rho associated coiled-coil kinase (ROCK) activation

Recently, we have proposed a new system of gene regulation called ‘drug or gene delivery system responding to cellular signals’ (D-RECS). In this system, transgene expression is activated in response to intracellular target protein kinases or proteases for safe, cell-specific gene delivery by using peptide-polymer conjugates. Here we applied this system to an intracellular Rho-associated coiled-coil kinase (ROCK) signal, which is activated abnormally in cardiovascular diseases. A ROCK responsive polymer consisting of neutral polymers in main chain and cationic ROCK substrate peptides in side chains was prepared and could form the complex with plasmid DNA. The complex was transferred into NIH3T3 cells with or without L-α-lysophosphatidic acid (LPA) that increases ROCK activity. At an N/P ratio of 2.0, a significant increase of the gene expression was identified in LPA-treated NIH3T3 cells, but was disappeared in NIH3T3 cells treated with ROCK specific inhibitor, Y-27632. These results suggest that the ROCK responsive polymer can regulate gene expression in response to ROCK activity.     

Development of sucrose stearate-based nanoemulsions and optimisation through γ-cyclodextrin

Nanoemulsions aimed at dermal drug delivery are usually stabilised by natural lecithins. However, lecithin has a high tendency towards self-aggregation and is prone to chemical degradation. Therefore, the aim of this study was to develop nanoemulsions with improved structure and long-term stability by employing a natural sucrose ester mixture as sole surfactant. A thorough comparison between the novel sucrose stearate-based nanoemulsions and corresponding lecithin-based nanoemulsions revealed that the sucrose ester is superior in terms of emulsifying efficiency, droplet formation as well as physical and chemical stability. The novel formulations exhibited a remarkably homogeneous structure in cryo TEM investigations, as opposed to the variable structure observed for lecithin-based systems. The in vitro skin permeation rates of lipophilic drugs from sucrose stearate nanoemulsions were comparable to those obtained with their lecithin-based counterparts. Furthermore, it was observed that addition of γ-cyclodextrin led to enhanced skin permeation of the steroidal drug fludrocortisone acetate from 9.99 ± 0.46 to 55.10 ± 3.67 μg cm⁻² after 24 h in the case of sucrose stearate-based systems and from 9.98 ± 0.64 to 98.62 ± 24.89 μg cm⁻² after 24 h in the case of lecithin-based systems. This enhancement effect was significantly stronger in formulations based on lecithin (P < 0.05), which indicates that synergistic mechanisms between the surfactant and the cyclodextrin are involved. Cryo TEM images suggest that the cyclodextrin is incorporated into the interfacial film, which might alter drug release rates and improve the droplet microstructure.