Therapeutic potential of injectable Nano-mupirocin liposomes for infections involving multidrug-resistant bacteria

Antibiotic resistance is a global health threat. There are a few antibiotics under development, and even fewer with new modes of action and no cross-resistance to established antibiotics. Accordingly, reformulation of old antibiotics to overcome resistance is attractive. Nano-mupirocin is a PEGylated nano-liposomal formulation of mupirocin, potentially enabling parenteral use in deep infections, as previously demonstrated in several animal models. Here, we describe extensive in vitro profiling of mupirocin and Nano-mupirocin and correlate the resulting MIC data with the pharmacokinetic profiles seen for Nano-mupirocin in a rat model. Nano-mupirocin showed no cross-resistance with other antibiotics and retained full activity against vancomycin-, daptomycin-, linezolid- and methicillin- resistant Staphylococcus aureus, against vancomycin-resistant Enterococcus faecium, and cephalosporin-resistant Neisseria gonorrhoeae. Following Nano-mupirocin injection to rats, plasma levels greatly exceeded relevant MICs for > 24 h, and a biodistribution study in mice showed that mupirocin concentrations in vaginal secretions greatly exceeded the MIC 90 for N. gonorrhoeae (0.03 µg/mL) for > 24 h. In summary, Nano-mupirocin has excellent potential for treatment of several infection types involving multiresistant bacteria. It has the concomitant benefits from utilizing an established antibiotic and liposomes of the same size and lipid composition as Doxil®, an anticancer drug product now used for the treatment of over 700,000 patients globally

Liposomal Bupivacaine (Bupigel) Demonstrates Minimal Local Nerve Toxicity in a Rabbit Functional Model

We previously reported the development of a novel formulation of an ultra-long-acting local anesthetic based on bupivacaine encapsulated in large multivesicular liposomes (Bupisomes) embedded in hydrogel. This formulation (Bupigel) prolonged bupivacaine release from the formulation in dissolution-like studies in vitro and analgesia in vivo in mouse, rat, and pig models. In this study we assessed Bupigel neurotoxicity on rabbit sciatic nerve using histopathology and electrophysiologic testing. Sciatic nerves of both hind limbs were injected dropwise with different formulations. Nerve conduction studies and needle electromyography two weeks after perineural administration showed signs of neural damage after injection of free lidocaine and bupivacaine, while there was no sign of neural damage after injection with saline, demonstrating the validity of the method. This test also did not show evidence of motor or sensory nerve damage after injection with liposomal bupivacaine at a dose 10-times higher than free bupivacaine. Histologically, signs of neural damage could be observed with lidocaine. Nerves injected with Bupigel showed mild signs of inflammation and small residues of hydrogel in granulomas, indicating a long residence time of the hydrogel at the site of injection, but no histopathological signs of nerve damage. This demonstrated that early signs of neural damage were detected electrophysiologically, showing the usefulness and sensitivity of electrodiagnostic testing in detection of neural damage from new formulations

PEGylated Liposomal Methyl Prednisolone Succinate does not Induce Infusion Reactions in Patients: A Correlation Between in Vitro Immunological and in Vivo Clinical Studies

PEGylated nanomedicines are known to induce infusion reactions (IRs) that in some cases can be life-threatening. Herein, we report a case study in which a patient with rare mediastinal and intracardiac IgG4-related sclerosing disease received 8 treatments of intravenously administered PEGylated liposomal methylprednisolone-succinate (NSSL-MPS). Due to the ethical requirements to reduce IRs, the patient received a cocktail of premedication including low dose of steroids, acetaminophen and H2 blockers before each infusion. The treatment was well-tolerated in that IRs, complement activation, anti-PEG antibodies and accelerated blood clearance of the PEGylated drug were not detected. Prior to the clinical study, an in vitro panel of assays utilizing blood of healthy donors was used to determine the potential of a PEGylated drug to activate complement system, elicit pro-inflammatory cytokines, damage erythrocytes and affect various components of the blood coagulation system. The overall findings of the in vitro panel were negative and correlated with the results observed in the clinical phase

Thermotropic characterization of SUV aqueous dispersions assessed from the DSC scans.

<p>Thermotropic characterization of SUV aqueous dispersions assessed from the DSC scans.</p

Small angle X-ray scattering (SAXS) measurements of NSSL-TMN.

<p><b>(A)</b> Radially integrated background-subtracted scattering data (symbols) of DMPC:DPPC NSSL with and without drug, at 4 and 37°C, as indicated in the figure. Note that the curves are shifted in the intensity axis only for clarity of presentation. The solid curves are the corresponding form-factor models of a stack of infinite slabs with a Gaussian electron density profile along the vertical direction. <b>(B)</b> The electron density profiles of the DMPC:DPPC NSSL bilayers (with and without drug at 4 and 37°C) along the normal direction. The density profiles are obtained by fitting the scattering data to the models (see A) with the software X+, choosing a Gaussian electron density profile for the liposome membrane [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130442#pone.0130442.ref040" target="_blank">40</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130442#pone.0130442.ref041" target="_blank">41</a>]. The profile is almost symmetric and very slightly affected by the temperature or the presence of the drug. The arrows point to the profile of the inner and outer PEG layers. <b>(C)</b> The integrated scattering patterns as a function of the magnitude of the scattering vector, q, for EPC liposomes. Note that the curves are shifted in the intensity axis for clarity of presentation. The scattering curves of the EPC NSSL with and without drug, at 4 and 37°C are very similar. These curves are analyzed using the software X+, as in (A). The liposome bilayer is described by a Gaussian electron density profile. <b>(D)</b> The electron density profile in the direction normal to the membrane, calculated using the software X+, is presented for EPC NSSL, with and without drug at 4 and 37°C. The density profile of the membrane is almost unaffected by the temperature or the presence of the drug. Notice that this profile is asymmetric, suggesting that the inner and the outer PEG layers (pointed by an arrow) of the liposome are different.</p

Nano-Drugs Based on Nano Sterically Stabilized Liposomes for the Treatment of Inflammatory Neurodegenerative Diseases - Fig 1

<p><b>(A)</b> DSC measurements. Samples of SUVs (DMPC:DPPC:Chol:PEG-DSPE, DMPC:DPPC:PEG-DSPE, DMPC:DPPC, DMPC:PEG-DSPE, DPPC:PEG-DSPE, DMPC, DPPC) in saline, and saline in the reference cell, were scanned in the range 10°-80°C, at the heating rate of 1°C/min. <b>(B)</b> Zooming in: Samples of SUVs DMPC:DPPC:Chol:PEG-DSPE, DMPC:DPPC:PEG-DSPE.</p

Nano-Drugs Based on Nano Sterically Stabilized Liposomes for the Treatment of Inflammatory Neurodegenerative Diseases

<div><p>The present study shows the advantages of liposome-based nano-drugs as a novel strategy of delivering active pharmaceutical ingredients for treatment of neurodegenerative diseases that involve neuroinflammation. We used the most common animal model for multiple sclerosis (MS), mice experimental autoimmune encephalomyelitis (EAE). The main challenges to overcome are the drugs’ unfavorable pharmacokinetics and biodistribution, which result in inadequate therapeutic efficacy and in drug toxicity (due to high and repeated dosage). We designed two different liposomal nano-drugs, i.e., nano sterically stabilized liposomes (NSSL), remote loaded with: (a) a “water-soluble” amphipathic weak acid glucocorticosteroid prodrug, methylprednisolone hemisuccinate (MPS) or (b) the amphipathic weak base nitroxide, Tempamine (TMN). For the NSSL-MPS we also compared the effect of passive targeting alone and of active targeting based on short peptide fragments of ApoE or of β-amyloid. Our results clearly show that for NSSL-MPS, active targeting is not superior to passive targeting. For the NSSL-MPS and the NSSL-TMN it was demonstrated that these nano-drugs ameliorate the clinical signs and the pathology of EAE. We have further investigated the MPS nano-drug’s therapeutic efficacy and its mechanism of action in both the acute and the adoptive transfer EAE models, as well as optimizing the perfomance of the TMN nano-drug. The highly efficacious anti-inflammatory therapeutic feature of these two nano-drugs meets the criteria of disease-modifying drugs and supports further development and evaluation of these nano-drugs as potential therapeutic agents for diseases with an inflammatory component.</p></div

Comparison of passively targeted NSSL and actively targeted peptide-conjugated NSSL.

<p><b>(A)</b> Representative fluorescent microscopy images comparing brain accumulation of NSSL and their payload as is (A, A1), β-amyloid NSSL(B,B1), and ApoE NSSL (C,C1) in healthy mice brain showing an increase in the amount of actively targeted NSSL and their payload accumulating, compared to passively targeted NSSL. <b>(B)</b> Comparison of the therapeutic efficacy of passively targeted NSSL-MPS and actively targeted peptide-conjugated NSSL-MPS in the acute EAE mice model. SJL mice were treated by IV injections on days 10, 12, 14 post-immunization with saline (control) (◆), NSSL-MPS (●), Apo-E NSSL-MPS (▲) or β-amyloid NSSL-MPS (<b>■</b>). * p-value < 0.0001.</p

Comparison of the therapeutic efficacy of EPC-based NSSL-TMN and DMPC:DPPC-based NSSL-TMN in acute EAE mice model.

<p>^a Significant difference from the control group P<0.0001</p><p>^b Significant difference from the EPC NSSL-TMN treated group P<0.001.</p><p>Comparison of the therapeutic efficacy of EPC-based NSSL-TMN and DMPC:DPPC-based NSSL-TMN in acute EAE mice model.</p