Polypseudorotaxane functionalized magnetic nanoparticles as a dual responsive carrier for roxithromycin delivery

Functionalization of graphene oxide with amphiphilic block copolymer to enhance antibacterial activity

Functionalization of GO with an amphiphilic block copolymer is designed with an aim to enhance its biocompatibility, however, long copolymer chains can screen the blade effect of GO to sacrifice its antimicrobial activities. To solve this problem, low molecular weight of poly(ethylene glycol) (PEG), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and their block copolymer were respectively introduced onto GO via an isophorone diisocyanate modified GO as a intermediate, followed by a solvent evaporation of an oil-in-water emulsion treatment (SE treatment) to induce block copolymer into polymer micelle via phase separation to refresh the sharp edges of GO. Block copolymer modified GO possessed similar dispersibility and stability to PEG modified GO, and even higher loading capacity of the hydrophobic drug than PHBV modified GO, illustrating its superior properties to homopolymer. PEG, PHBV and their block copolymer modified GO were nontoxic towards ATDC5 cells while cultured for 3 days and compatible with erythrocytes within 8 h. SE treatment enhanced greatly the loading capacity of the hydrophobic drug and the accumulative release reached 91.3% within 24 h. The inhibition zone of the block copolymer modified GO was 14.1 mm and 14.8 mm against E. coli and S. aureus, comparable to that of PEG modified GO. The bacterial reduction rate of the copolymer micelle modified GO was 87.1% and 82.7% towards E. coli and S. aureus, much greater than that of PEG, PHBV and their block copolymer modified GO at a concentration of 1 mg/mL. The antibiofilm capacity of the copolymer micelle modified GO were equal to that of PEG modified, demonstrating its great promise in tissue engineering application for repair of infected tissue defects.

Cyclodextrins and derivatives in drug delivery: New developments, relevant clinical trials, and advanced products

Cyclodextrins (CD) and derivatives are functional excipients that can improve the bioavailability of numerous drugs. Because of their drug solubility improving properties they are used in many pharmaceutical products. Furthermore, the stability of small molecular drugs can be improved by the incorporation in CDs and an unpleasant taste and smell can be masked. In addition to well-established CD derivatives including hydroxypropyl-β-CD, hydroxypropyl-γ-CD, methylated- β-CD and sulfobutylated- β-CD, there are promising new derivatives in development. In particular, CD-based polyrotaxanes exhibiting cellular uptake enhancing properties, CD-polymer conjugates providing sustained drug release, enhanced cellular uptake, and mucoadhesive properties, and thiolated CDs showing mucoadhesive, in situ gelling, as well as permeation and cellular uptake enhancing properties will likely result in innovative new drug delivery systems. Relevant clinical trials showed various new applications of CDs such as the formation of CD-based nanoparticles, stabilizing properties for protein drugs or the development of ready-to-use injection systems. Advanced products are making use of various benefical properties of CDs at the same time. Within this review we provide an overview on these recent developments and take an outlook on how this class of excipients will further shape the landscape of drug delivery.

Acid-Responsive Macroporous Silica Nanoparticles for Bcl-2-Functional-Converting Peptide Release and Synergism with Celastrol for Enhanced Therapy against Resistant Cancer

Combination of chemotherapeutics with polypeptide/protein drugs has been demonstrated to be an effective approach for treatment against cancer multidrug resistance. However, due to the low biostability and weak cell penetrating ability of biomacromolecules, intracellular delivery and release of biomacromolecules in a spatiotemporally controllable manner in target sites in vivo face great challenges, and synergistic effects will not be achieved as expected just by simple drug combination. Here, we conceived an inspired strategy to combat the drug-resistant tumors by fabricating multiarm PEG-gated large pore-sized mesoporous silica nanoparticles for the Bcl-2-functional-converting peptide (denoted as N9@M-CA∼8P) payload and controlled release and realizing synergistic effects with celastrol integration at a low dosage as a curative sensitizer. Our results demonstrated that the N9 peptide could be pH-responsively released from the macropores of the M-CA∼8P nanosystem both in simulated physiological environments and in cancer cells and at tumor sites. Biosafe and enhanced therapeutic outcomes (90% tumor inhibition) were obtained by combination of the N9@M-CA∼8P nanosystem with celastrol coordinatively inducing mitochondrion-mediated cell apoptosis in resistant cancer cell lines and in the corresponding xenografted mice models. Overall, this study provides convincing evidence for effective and safe resistant cancer treatment through a stimulus-responsive biomacromolecule nanosystem combined with a low dosage of a natural compound.

Fast dissolving nanofiber mat for the local antimicrobial application of roxithromycin in oral cavity

Fast disintegrating and dissolving nanofiber (NF) mat was devised to deliver roxithromycin for the treatment of the respiratory tract infection. NF membrane was made by an electrospinning process with poly(vinyl alcohol) (PVA), hydroxypropyl-β-cyclodextrin (HP-β-CD), and d-α-tocopheryl polyethylene glycol succinate (TPGS) for local application of roxithromycin. Roxithromycin has a poor water solubility thus HP-β-CD is introduced for enhancing drug solubility by forming an inclusion complex in this study. The addition of TPGS provided multiple roles such as accelerating wetting, disintegration, and dissolution speed and overcoming bacterial resistance. Roxithromycin was successfully entrapped in NF structure and drug amorphization occurred during the electrospinning process. PVA/HP-β-CD/TPGS/roxithromycin (PHTR) NF exhibited faster wetting, disintegration, and dissolution speed rather than the other NF mats. PHTR NF displayed higher antibacterial potentials in Gram-negative bacteria (E. coli) and Gram-positive bacteria (S. aureus) compared to other NF mat formulations. The administration of PHTR NF to oral cavity in pneumococcal disease mouse model provided the most efficient therapeutic potentials in lung tissue. Designed multiple phase-based NF mat may be one of powerful local drug delivery systems for the therapy of respiratory tract infection.

The immuno-reactivity of polypseudorotaxane functionalized magnetic CDMNP-PEG-CD nanoparticles

pH‐magnetic dual‐responsive nanocomposites have been widely used in drug delivery and gene therapy. Recently, a polypseudorotaxane functionalized magnetic nanoparticle (MNP) was developed by synthesizing the magnetic nanoparticles with cyclodextrin (CD) molecules (CDMNP) via polyethylene glycol (PEG) (CDMNP‐PEG‐CD). The purpose of this study was to explore the antigenicity and immunogenicity of the nanoparticles in vivo prior to their further application explorations. Here, nanoparticles were assessed in vivo for retention, bio‐distribution and immuno‐reactivity. The results showed that, once administered intravenously, CDMNP‐PEG‐CD induced a temporary blood monocyte response and was cleared effectively from the body through the urine system in mice. The introduction of β‐CD and PEG/β‐CD polypseudorotaxane on SiO₂ magnetic nanoparticles (SOMNP) limited particle intramuscular dispersion after being injected into mouse gastrocnemius muscle (GN), which led to the prolonged local inflammation and muscle toxicity by CDMNP and CDMNP‐PEG‐CD. In addition, T cells were found to be more susceptible for β‐CD–modified CDMNP; however, polypseudorotaxane modification partially attenuated β‐CD–induced T cell response in the implanted muscle. Our results suggested that CDMNP‐PEG‐CD nanoparticles or the decomposition components have potential to prime antigen‐presenting cells and to break the muscle autoimmune tolerance.