PEGylation of paclitaxel largely improves its safety and anti-tumor efficacy following pulmonary delivery in a mouse model of lung carcinoma

Pulmonary delivery offers an attractive route of administration for chemotherapeutic agents, with the advantages of high drug concentrations locally and low side effects systemically. However, fast clearance mechanisms result in short residence time of small molecule drugs in the lungs. Moreover, the local toxicity induced by antineoplastic drugs is considered a major obstacle for the clinical application of inhaled chemotherapy. In this study, we explored the utility of 6 kDa and 20 kDa polyethylene glycol-paclitaxel (PEG-PTX) conjugates to retain paclitaxel within the lungs, achieve its sustained release locally, and thereby, improve its efficacy and reduce its pulmonary toxicity. The conjugates increased the maximum tolerated dose of paclitaxel by up to 100-fold following intratracheal instillation in healthy mice. PEG-PTX conjugates induced lung inflammation. However, the inflammation was lower than that induced by an equivalent dose of the free drug and it was reversible. Conjugation of paclitaxel to both PEG sizes significantly enhanced its anti-tumor efficacy following intratracheal instillation of a single dose in a Lewis lung carcinoma model in mice. PEG-PTX 20k showed equivalent efficacy as PEG-PTX 6k delivered at a 2.5-fold higher dose, suggesting that the molecular weight of the conjugate plays a role in anti-cancer activity. PEG-PTX 20k conjugate presented a prolonged residency and a sustained paclitaxel release within the lungs. This study showed that PEGylation of paclitaxel offers a potential delivery system for inhalation with improved anti-cancer efficacy, prolonged exposure of lung-resident tumors to the antineoplastic drug and reduced local toxicity

Injectable alginate hydrogel loaded with GDNF promotes functional recovery in a hemisection model of spinal cord injury

We hypothesized that local delivery of GDNF in spinal cord lesion via an injectable alginate hydrogel gelifying in situ would support spinal cord plasticity and functional recovery. The GDNF release from the hydrogel was slowed by GDNF encapsulation in microspheres compared to non-formulated GDNF (free GDNF). When injected in a rat spinal cord hemisection model, more neurofilaments were observed in the lesion when the rats were treated with free GDNF-loaded hydrogels. More growing neurites were detected in the tissues surrounding the lesion when the animals were treated with GDNF microsphere-loaded hydrogels. Intense GFAP (astrocytes), low III tubulin (neural cells) and RECA-1 (endothelial cells) stainings were observed for non-treated lesions while GDNF-treated spinal cords presented less GFAP staining and more endothelial and nerve fiber infiltration in the lesion site. The animals treated with free GDNF-loaded hydrogel presented superior functional recovery compared with the animals treated with the GDNF microsphere-loaded hydrogels and non-treated animals

Stimuli‐Responsive Multifunctional Nanomedicine for Enhanced Glioblastoma Chemotherapy Augments Multistage Blood‐to‐Brain Trafficking and Tumor Targeting

Minimal therapeutic advances have been achieved over the past two decades for glioblastoma (GBM), which remains an unmet clinical need. Here, hypothesis‐driven stimuli‐responsive nanoparticles (NPs) for docetaxel (DTX) delivery to GBM are reported, with multifunctional features that circumvent insufficient blood‐brain barrier (BBB) trafficking and lack of GBM targeting—two major hurdles for anti‐GBM therapies. NPs are dual‐surface tailored with a i) brain‐targeted acid‐responsive Angiopep‐2 moiety that triggers NP structural rearrangement within BBB endosomal vesicles, and ii) L‐Histidine moiety that provides NP preferential accumulation into GBM cells post‐BBB crossing. In tumor invasive margin patient cells, the stimuli‐responsive multifunctional NPs target GBM cells, enhance cell uptake by 12‐fold, and induce three times higher cytotoxicity in 2D and 3D cell models. Moreover, the in vitro BBB permeability is increased by threefold. A biodistribution in vivo trial confirms a threefold enhancement of NP accumulation into the brain. Last, the in vivo antitumor efficacy is validated in GBM orthotopic models following intratumoral and intravenous administration. Median survival and number of long‐term survivors are increased by 50%. Altogether, a preclinical proof of concept supports these stimuli‐responsive multifunctional NPs as an effective anti‐GBM multistage chemotherapeutic strategy, with ability to respond to multiple fronts of the GBM microenvironment

Transdermal delivery of timolol and atenolol using electroporation and iontophoresis in combination: a mechanistic approach.

PURPOSE: The purpose of this work was to study the effect of electroporation on iontophoretic transport of two beta-blockers, timolol (lipophilic) and atenolol (hydrophilic), and to have a better understanding of the mechanism of combination. METHODS: The transdermal delivery of these beta-blockers through human stratum corneum was studied in three-compartment diffusion cells. The transport of mannitol was evaluated to assess the electroosmotic flow. RESULTS: The iontophoretic transport of timolol was decreased by electroporation because the high accumulation of the lipophilic cation timolol in the stratum corneum resulted in a decrease of electroosmosis. In contrast, electroosmosis was not affected by atenolol, and the iontophoretic transport of atenolol was increased by electroporation. CONCLUSIONS: Using two different beta-blockers, we showed that lipophilicity and positive charges affect the electrotransport of drugs. Understanding the effect of the physicochemical properties of the drug, as well as the electrical parameters, is thus essential for the optimization of transdermal drug delivery by a combination of electroporation and iontophoresis

Assessment of Hyperosmolar Blood-Brain Barrier Opening in Glioblastoma via Histology with Evans Blue and DCE-MRI.

While the blood-brain barrier (BBB) is often compromised in glioblastoma (GB), the perfusion and consequent delivery of drugs are highly heterogeneous. Moreover, the accessibility of drugs is largely impaired in the margins of the tumor and for infiltrating cells at the origin of tumor recurrence. In this work, we evaluate the value of methods to assess hemodynamic changes induced by a hyperosmolar shock in the core and the margins of a tumor in a GB model. Osmotic shock was induced with an intracarotid infusion of a hypertonic solution of mannitol in mice grafted with U87-MG cells. The distribution of fluorescent dye (Evans blue) within the brain was assessed via histology. Dynamic contrast-enhanced (DCE)-MRI with an injection of Gadolinium-DOTA as the contrast agent was also used to evaluate the effect on hemodynamic parameters and the diffusion of the contrast agent outside of the tumor area. The histological study revealed that the fluorescent dye diffused much more largely outside of the tumor area after osmotic shock than in control tumors. However, the study of tumor hemodynamic parameters via DCE-MRI did not reveal any change in the permeability of the BBB, whatever the studied MRI parameter. The use of hypertonic mannitol infusion seems to be a promising method to increase the delivery of compounds in the margins of GB. Nevertheless, the DCE-MRI analysis method using gadolinium-DOTA as a contrast agent seems of limited value for determining the efficacy of opening the BBB in GB after osmotic shock

Impact of formulation and methods of pulmonary delivery on absorption of parathyroid hormone (1-34) from rat lungs

The aim of this work was to optimize the absorption of parathyroid hormone 1-34 (PTH) from the lungs by determining factors favoring its transport from the air spaces into the bloodstream. We simultaneously conducted pharmacokinetic and regional lung deposition studies in vivo in the rat following intratracheal administration of PTH in solution or dry powder form. Dry powders of PTH or albumin were prepared by spray-drying using lactose and dipalmitoylphosphatidylcholine (DPPC). Deposition in the trachea, peripheral, and central lobe sections was assessed after tissue grinding using albumin as a marker. The method of intratracheal instillation had a significant impact on PTH absorption from the lungs, and the deeper the deposition within the respiratory tract, the higher the absorption. Inhalation of the PTH powder resulted in high systemic bioavailability despite deposition of the formulation principally in upper airways. We demonstrated that the increased absorption resulted from DPPC that had permeation enhancer properties even though it was abundantly present locally in pulmonary surfactant. Optimization of PTH absorption from the lungs could be attained by targeting the peripheral lungs as well as codelivering DPPC

Comparison of active, passive and magnetic targeting to tumors of multifunctional paclitaxel/SPIO-loaded nanoparticles for tumor imaging and therapy

Multifunctional nanoparticles combining therapy and imaging have the potential to improve cancer treatment by allowing personalized therapy. Herein, we aimed to compare in vivo different strategies in terms of targeting capabilities: (1) passive targeting via the EPR effect, (2) active targeting of αvβ3 integrin via RGD grafting, (3) magnetic targeting via a magnet placed on the tumor and (4) the combination of magnetic targeting and active targeting of αvβ3 integrin. For a translational approach, PLGA-based nanoparticles loaded with paclitaxel and superparamagnetic iron oxides were used. Electron Spin Resonance spectroscopy and Magnetic Resonance Imaging (MRI) were used to both quantify and visualize the accumulation of multifunctional nanoparticles into the tumors. We demonstrate that compared to untargeted or single targeted nanoparticles, the combination of both active strategy and magnetic targeting drastically enhanced (i) nanoparticle accumulation into the tumor tissue with an 8-fold increase compared to passive targeting (1.12% and 0.135% of the injected dose, respectively), (ii) contrast in MRI (imaging purpose) and (iii) anti-cancer efficacy with a median survival time of 22days compared to 13 for the passive targeting (therapeutic purpose). Double targeting of nanoparticles to tumors by different mechanisms could be a promising translational approach for the management of therapeutic treatment and personalized therapy

Validation of a method for the quantitation of ghrelin and unacylated ghrelin by HPLC.

An HPLC/UV method was first optimized for the separation and quantitation of human acylated and unacylated (or des-acyl) ghrelin from aqueous solutions. This method was validated by an original approach using accuracy profiles based on tolerance intervals for the total error measurement. The concentration range that achieved adequate accuracy extended from 1.85 to 59.30microM and 1.93 to 61.60microM for acylated and unacylated ghrelin, respectively. Then, optimal temperature, pH and buffer for sample storage were determined. Unacylated ghrelin was found to be stable in all conditions tested. At 37 degrees C acylated ghrelin was stable at pH 4 but unstable at pH 7.4, the main degradation product was unacylated ghrelin. Finally, this validated HPLC/UV method was used to evaluate the binding of acylated and unacylated ghrelin to liposomes

Active and passive tumor targeting of a novel poorly soluble cyclin dependent kinase inhibitor, JNJ-7706621.

The anti-cancer cyclin dependent kinase (CDK) inhibitors are poorly soluble drugs. The aims of this work were (i) to formulate a novel CDK inhibitor, JNJ-7706621, in polymeric micelles and nanoparticles, (ii) to compare passive and active targeting on tumor growth and (iii) to evaluate the potential synergy of JNJ-7706621 with Paclitaxel. Therefore, JNJ-7706621 was encapsulated in self-assembling diblock copolymers made up of varepsilon-caprolactone (CL) and trimethylene carbonate (TMC) (PEG-p-(CL-co-TMC)) polymeric micelles and in (Poly(lactide-co-glycolide)) (PLGA)-based PEGylated nanoparticles (passive targeting) as well as in RGD-grafted nanoparticles (active targeting). In vivo, the transplantable liver tumor growth was more decreased by active targeting with RGD-grafted nanoparticles than by passive targeting with micelles or ungrafted nanoparticles. Moreover, a synergy between JNJ-7706621 and Paclitaxel was demonstrated. Therefore, active targeting of JNJ-7706621-loaded nanocarriers may be considered as an effective anti-cancer drug delivery system for cancer chemotherapy, particularly in combination with Paclitaxel